Method of treating or inhibiting the development of an infection

Abstract

Disclosed are compositions comprising poly(hexamethylene) biguanide (PHMB) or a pharmaceutically or veterinary acceptable salt thereof, a chelating agent, and a buffering agent and their use for disrupting and eradicating biofilms. The invention also relates to the use of the compositions for treating or inhibiting the development of an infection caused by a bacterium selected from the group consisting of Burkholderia spp., Serratia spp., Enterococcus spp. and Corynebacterium spp. and / or increasing the susceptibility of such bacterial strains to antibiotics.

Description

TITLE OF THE INVENTIONMETHOD OF TREATING OR INHIBITING THE DEVELOPMENT OF AN INFECTION

[0001] This application claims priority to Australian Provisional Patent Application No. 2024903046 entitled "Method of treating or inhibiting the development of an infection" filed 23 September 2024, the contents of which are incorporated herein by reference in their entirety.FIELD OF THE INVENTION

[0002] This invention relates generally to compositions comprising poly(hexamethylene) biguanide (PHMB) or a pharmaceutically or veterinary acceptable salt thereof, a chelating agent, and a buffering agent and their use for disrupting and eradicating biofilms. The invention also relates to the use of the compositions for treating or inhibiting the development of an infection caused by a bacterium selected from the group consisting of Burkholderia spp., Serratia spp., Enterococcus spp. and Corynebacterium spp. and / or increasing the susceptibility of such bacterial strains to antibiotics.BACKGROUND OF THE INVENTION

[0003] The reference in this specification to any prior publication (or information derived from it), or to any matter which is known, is not and should not be taken as an acknowledgment or admission or any form of suggestion that the prior publication (or information derived from it) or known matter forms part of the common general knowledge in the field of endeavour to which this specification relates.

[0004] Microorganisms exist in two forms: planktonic and biofilm. Biofilms are a community of sessile bacteria that are embedded in an extracellular polymeric substance (EPS) and attached to a surface. Microbial colonies form biofilms in response to stress as part of the survival mechanism and produce EPS. The EPS is a matrix comprising proteins, polysaccharides, lipids, extracellular deoxyribonucleic acid and fatty acids secreted by the microorganism for protection against external threats such as antimicrobial substances. EPS also traps exogenous materials such as nucleic acids, proteins minerals, nutrients, and cell-wall components observed in the local environment. Biofilms are widespread and assist microorganisms in surviving in harsh competitive environments. In vivo, biofilm formation plays an essential role in evading the host defence mechanisms and antimicrobial therapy. In particular, EPS forms a physical barrier around the bacteria to prevent penetration of antimicrobials and plays a significant role in antimicrobial resistance. Indeed, the minimal inhibitory concentration of sessile bacteria inside the biofilm can be at least 100 to 1000 times greater than planktonic bacteria of the same species.

[0005] Biofilms are clinically significant in both human and veterinary medicine and are a major factor in the persistence of chronic infections. Biofilms are known culprits in medical device-associated infections, which are difficult to eradicate and challenging to treat with antibiotics, resulting in device failure and, therefore, treatment failure. This leads to the replacement of the contaminated device with a new device, thereby resulting in an escalation in mortality, morbidity, recovery period and cost of therapy.

[0006] Ventilator-associated pneumonia is the most common nosocomial or hospital-associated infection in patients receiving mechanical ventilation. Microbial adhesion to the surface of the endotracheal tube, rapid biofilm formation and migration of biofilm to the lung tissue are crucial steps in ventilator-associated pneumonia pathogenesis. Microbial biofilms may also form on contaminated implanted devices, such as orthopaedic implants, cochlear implants, dental implants or vascular catheters and may cause life-threatening infections such as catheter-related bloodstream infections. Skin colonisation around the catheter insertion site by microorganisms, their migration, adhesion to the catheter surface and relocation along the catheter, where microbial colonies join to its polymeric surfaces and start to architect biofilm is the key mechanism of life-threatening catheter-related bloodstream infections. The most commonly reported pathogenic microorganisms producing biofilm in hospital-associated infection associated with indwelling medical devices are Escherichia coli, Staphylococcus aureus, Klebsiella spp., Pseudomonas aeruginosa, Proteus spp., Enterococcus faecalis and others. Corynebacterium amycolatum is also increasingly being associated with infections of medical devices.

[0007] Multidrug-resistant pathogens, for example some Enterobacterales (5. coli, K. pneumoniae, Serratia spp. and Proteus spp.), Acinetobacter baumannii, Pseudomonas aeruginosa and Staphylococcus spp., are a major challenge for human and veterinary medicine. These pathogens tend to acquire various multidrug-resistant mechanisms and thereby be unaffected by most antimicrobial agents. The World Health Organization has given them the highest "critical-priority" status. Methicillin resistance has occurred in Staphylococcus spp. by mutation of a penicillin-binding protein, which is a chromosome-encoded protein. This type of resistance is transferred between the bacteria by bacteriophages. This is one of the only medically relevant examples of chromosome- mediated drug resistance by phage transduction. Most of these "critical-priority" pathogens have the ability to form biofilms.

[0008] Gram-negative pathogens in particular have a propensity to form biofilms and escape antimicrobial activity through various resistance mechanisms. The ability for Pseudomonas spp. to form biofilms was found to be over 90%. Multidrug-resistant A. baumannii clinical isolates can form large quantities of biofilms on different living and non-living surfaces. Biofilm formation often results in infections that are recalcitrant to treatment, which is creating increasing concerns over antimicrobial resistance.

[0009] Currently, biofilms in dogs are typically treated with antibiotics. However, several Gram-negative bacteria, particularly Burkholderia spp. are multi-drug resistant or have the ability to acquire resistance to antibiotics quickly. Burkholderia cepacia complex is an emerging cause of opportunistic infections and is reported to cause deep pyodermas and sepsis in dogs. It has been associated with disease in humans with cystic fibrosis.

[0010] Canine otitis externa is a common disease in veterinary medicine. It is a multifactorial condition that is caused by a primary, inciting condition leading to secondary inflammation and infections. Primary conditions include allergies (e.g. food allergy or atopic dermatitis), parasite infection (e.g. with Otodectes cynotis), foreign bodies, neoplasia and endocrine disorders (e.g. hypothyroidism and hyperad renocorticism). These primary conditions lead to bacterial and yeast colonisation of the ear canal epithelium and cause inflammation. The most common micro-organisms associated with canine otitis externa are Staphylococcus pseudintermedius, Malassezia pachydermatis, Pseudomonas aeruginosa, Streptococcus spp., Proteus mirabilis and Escherichia coli. These pathogens can form biofilms which makes them less susceptible to antimicrobial agents.

[0011] Improved agents for eradicating biofilms and treating infections caused by biofilm-forming and / or drug-resistant microorganisms are desired.SUMMARY OF THE INVENTION

[0012] The present invention is predicated in part on the determination that a composition comprising poly(hexamethylene) biguanide (PHMB) or a pharmaceutically or veterinary acceptable salt thereof, a chelating agent and a buffering agent is able to eradicate biofilms. The inventor has determined that such composition is able to eradicate biofilms formed by bacterial species that are known to be resistant to standard antibiotics, such as Burkholderia spp., Serratia spp., Enterococcus spp. and Corynebacterium spp. and increases the susceptibility of the bacterium to antibiotics. Based on this activity, the inventors conceived that the compositions will be useful for disrupting and eradicating biofilms, treating or inhibiting the development of an infection and / or increasing the susceptibility of bacteria to antibiotics.

[0013] Accordingly, in one aspect, there is provided a method of disrupting or eradicating a biofilm, comprising contacting the biofilm with a composition comprising PHMB or a pharmaceutically or veterinary acceptable salt thereof, a chelating agent and a buffering agent.

[0014] In some embodiments, the biofilm comprises at least one bacterium selected from the group consisting of Staphylococcus pseudintermedius, Pseudomonas aeruginosa, Escherichia coli, Proteus mirabilis, Streptococcus canis, Burkholderia cepacia,Burkholderia cenocepacia, Burkholderia multivorans, Staphylococcus aureus, Klebsiella oxytoca, Klebsiella pneumoniae, Klebsiella aerogenes, Enterococcus faecalis, Enterococcus canintestini, Corynebacterium auriscanis, Corynebacterium amycolatum and Serratia marcescens. In particular embodiments, the bacterium is resistant to at least one antibiotic.

[0015] In alternative embodiments, the biofilm comprises Malassezia pachydermatis.

[0016] In some embodiments, the buffering agent is Tris or a pharmaceutically or veterinary acceptable salt thereof.

[0017] In another aspect, there is provided a method of treating or inhibiting the development of an infection caused by a bacterium selected from the group consisting of Burkholderia spp., Serratia spp., Enterococcus spp. and Corynebacterium spp. in a subject, comprising administering a composition comprising PHMB or a pharmaceutically or veterinary acceptable salt thereof, a chelating agent and a buffering agent to the subject.

[0018] In some embodiments, the bacterium is resistant to one or more antibiotics.

[0019] In some embodiments, the bacterium is selected from the group consisting of Burkholderia spp., Serratia spp. and Corynebacterium spp.. In some embodiments, the bacterium is selected from the group consisting of Burkholderia spp. (e.g. B. cepacia, B. cenocepacia or B. multivorans') and Serratia spp. (e.g. S. marcescens). In some embodiments, the bacterium is E. faecalis or E. canintestini. In some embodiments, the bacterium is C. auriscanis, C. amycolatum or Corynebacterium urealyticum.

[0020] In particular embodiments, the bacterium is in the form of a biofilm.

[0021] In some embodiments, the buffering agent is Tris or a pharmaceutically or veterinary acceptable salt thereof.

[0022] In a further aspect, there is provided a method of conferring antibiotic susceptibility to a resistant bacterium, comprising contacting the bacterium with a composition comprising PHMB or a pharmaceutically or veterinary acceptable salt thereof, a chelating agent and a buffering agent, wherein the bacterium is selected from the group consisting of Burkholderia spp., Serratia spp., Enterococcus spp. and Corynebacterium spp..

[0023] In some embodiments, the bacterium is selected from the group consisting of Burkholderia spp., Serratia spp. and Corynebacterium spp.. In some embodiments, the bacterium is selected from the group consisting of Burkholderia spp. (e.g. B. cepacia, B. cenocepacia or B. multivorans) and Serratia spp. (e.g. S. marcescens).In some embodiments, the bacterium is E. faecalis or E. canintestini. In some embodiments, the bacterium is C. auriscanis, C. amycolatum or Corynebacterium urealyticum.

[0024] In particular embodiments, the bacterium is in the form of a biofilm.

[0025] In some embodiments, the buffering agent is Tris or a pharmaceutically or veterinary acceptable salt thereof.

[0026] In another aspect, there is provided a method of increasing the susceptibility of a bacterium to an antibiotic, comprising contacting the bacterium with a composition comprising PHMB or a pharmaceutically or veterinary acceptable salt thereof, a chelating agent and a buffering agent, wherein the bacterium is selected from the group consisting of Burkholderia spp., Serratia spp., Enterococcus spp. and Corynebacterium spp..

[0027] In some embodiments, the bacterium is selected from the group consisting of Burkholderia spp., Serratia spp. and Corynebacterium spp.. In some embodiments, the bacterium is selected from the group consisting of Burkholderia spp. (e.g. B. cepacia, B. cenocepacia or B. multivorans') and Serratia spp. (e.g. S. marcescens). In some embodiments, the bacterium is E. faecalis or E. canintestini. In some embodiments, the bacterium is C. auriscanis, C. amycolatum or Corynebacterium urealyticum.

[0028] In particular embodiments, the bacterium is in the form of a biofilm.

[0029] In some embodiments of any of the aspects above, the chelating agent is glycinate, iminodiacetic acid, nitrilotriacetic acid, nitrilotripropionic acid, ethylenediamine tetraacetic acid (EDTA), diethylenetriamine pentaacetic acid, ethylene glycol-bis(|3- aminoethyl ether)- / V, / V, / V', / V'-tetraacetic acid, l,2-bis(o-aminophenoxy)ethane- / V, / V, / V', / V / - tetraacetic acid, l,4,7-triazacyclononane-l,4,7-triacetic acid, 2, 2', 2", 2" '-(1,4, 7,10- tetraazacyclododecane-l,4,7,10-tetrayl)tetraacetic acid, nicotimamine, ethylenediamine- / V, / V'-bis(2-hydroxyphenylacetic acid), ethylenediamine disuccinic acid, 2-hydroxyethyl- ethylenediamine-triacetic acid, 1,6-diamino-hexamethylene-tetraacetic acid, 1,2-diamino- cyclohexane tetraacetic acid, O,O9-bis(2-aminoethyl)-ethyleneglycol-tetraacetic acid, 1,3- diaminopropane-tetraacetic acid, / V, / V-bis(2-hydroxybenzyl)ethylenediamine- / V, / V-diacetic acid, ethylenediamine- / V, / V9-diacetic acid, ethylenediamine- / V, / V9-dipropionic acid, triethylenetetraamine hexaacetic acid, 7,19,30-trioxa-l,4,10,13,16,22,27,33- octaazabicyclo[ll,ll,ll]pentatriacontane (O-bis-tren), ethylenediamine- / V, / V9- bis(methylenephosphonic acid), iminodiacetic acid, / V, / V-bis(2-hydroxyethyl)glycine, 1,3- diamino-2-hydroxypropane-tetraacetic acid, 1,2-diaminopropane-tetraacetic acid, ethylenediamine-tetrakis(methylenephosphonic acid), / V-(2-hydroxyethyl)iminodiacetic acid, triethylenetetramine-hexaacetic acid, deferoxamine, dimercaprol, citrate,penicillamine, etidronate, a macrocyclic polyether, polyaspartic acid, methylglycinediacetic acid, glutamic diacetic acid, gluconic acid, or a pharmaceutically or veterinary acceptable salt of any of the foregoing.

[0030] In particular embodiments, the chelating agent is EDTA or a pharmaceutically or veterinary acceptable salt thereof. In some embodiments, the chelating agent is disodium EDTA, trisodium EDTA, tetrasodium EDTA, dipotassium EDTA, tripotassium EDTA, lithium EDTA, dilithium EDTA, ammonium EDTA, diammonium EDTA and calcium disodium EDTA; especially disodium EDTA.

[0031] In some embodiments of any of the aspects above, the buffering agent is tris(hydroxymethyl)aminomethane (Tris), triethylamine, triethylenetetramine, tetraethylethylenediamine, tetramethylenediamine, / V, / V'-diethyl- / V, / V'-bis(sulfopropyl)- ethylenediamine, / V, / V'-diethylpiperazine, piperazine- / V, / V'-bis(alkylsulfonic acids), ( / V-morpholino)alkylsulfonic acids, 2-aminoethanol, 2-amino-2-methyl-l-propanol, triethanolamine, 2-amino-2-methyl-l,3-propanediol, bis-(2-hydroxyethyl)imino- tris(hydroxymethyl)methane, 2-dimethylamino-2-methyl-l-propanol, 2-amino-2-ethyl- 1,3-propanediol, l,3-bis(tris[hydroxymethyl]methylamino)propane, / V, / V-bis(2- hydroxyethyl)-2-aminoethanesulfonic acid, / V-[tris(hydroxymethyl)methyl]-3- aminopropanesulfonic acid, / V, / V-bis(2-hydroxyethyl)glycine, / V, / V-bis(2- hydroxyethyl)taurine, diethanolamine, / V-tris(hydroxymethyl)methylglycine or a pharmaceutically or veterinary acceptable salt of any of the foregoing. In particular embodiments, the buffering agent is Tris or a pharmaceutically or veterinary acceptable salt thereof.

[0032] In some embodiments of any of the aspects above, the composition comprises poly(hexamethylene) biguanide HCI.

[0033] In some embodiments of any of the aspects above, the composition comprises PHMB or a pharmaceutically or veterinary acceptable salt thereof in an amount in the range of from about 0.025% to about 0.2% w / v, about 0.05% to about 0.15% w / v or about 0.05% w / v or about 0.1% w / v.

[0034] In some embodiments of any of the aspects above, the composition comprises the chelating agent in an amount in the range of from about 0.1% to about 0.2% w / v or about 0.12% w / v.

[0035] In some embodiments of any of the aspects above, the composition comprises the buffering agent in an amount in the range of from about 0.5% to about 0.8% w / v or about 0.605% w / v.

[0036] In further embodiments of any of the aspects above, the composition further comprises a rheology modifier.

[0037] In some embodiments of any of the aspects above, the composition further comprises an aqueous carrier.

[0038] In some embodiments of any of the aspects above, the composition comprises PHMB or a pharmaceutically or veterinary acceptable salt thereof and the chelating agent in a weight ratio of from about 1 : 1 to about 1:4 or about 1: 1.2 to about 1 :2.4.BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 is a series of graphs presenting the biofilm quantification for two high biofilm-producing isolates each of f. coli (A), M. pachydermatis (B), P. aeruginosa (C) and S. pseudintermedius (D) exposed to two-fold serial dilutions of Composition A.

[0040] Figure 2 is a series of graphs presenting the biofilm quantification for two high biofilm-producing isolates each of f. coli (A), M. pachydermatis (B), P. aeruginosa (C) and S. pseudintermedius (D) exposed to two-fold serial dilutions of N-acetylcysteine (NAC) (pg / mL).

[0041] Figure 3 is a series of graphs presenting the biofilm quantification for two high biofilm-producing isolates each of f. coli (A), M. pachydermatis (B), P. aeruginosa (C) and S. pseudintermedius (D) exposed to two-fold serial dilutions of Tris-EDTA (Tris-EDTA; pg / mL).

[0042] Figure 4 is a series of graphs presenting the crystal violet (CV) staining of reference strains bacterial biofilms upon exposure to Composition A (PHMB 2 g / L), Composition B (PHMB 1 g / L), NAC 20 g / L and Tris-EDTA 1.2 g / L. Biofilms of (A) B. cepacia, (B) E. coli, (C) P. aeruginosa, (D) S. aureus and (E) S. pseudintermedius were challenged with Composition A, Composition B, NAC and Tris-EDTA for 24h at 37°C. The plates were washed, and biofilms were heat fixed. Biofilms were stained with CV and CV intensity was recorded at 570 nm using a Tecan plate reader. The experiments were conducted in duplicate and repeated twice on different days. Values were expressed as mean and standard error of the mean (SEM) of two technical replicates. The plots represent the mean and SEM of two independent experiments.

[0043] Figure 5 is a series of graphs presenting the CV staining of bacterial biofilm from Pseudomonas spp. clinical isolates and upon exposure to Composition A (PHMB 2 g / L), Composition B (PHMB 1 g / L), NAC 20 g / L and Tris-EDTA 1.2 g / L. Biofilms of (A) Aliza, (B) Bear, (C) Gator, (D) Sam and (E) Wilfred were challenged with Composition A, Composition B, NAC and Tris-EDTA for 24h at 37°C. The plates were washed, and biofilms were heat fixed. Biofilms were stained with CV and CV intensity was recorded at 570 nm using Tecan plate reader. The experiments were conducted in duplicate and repeated twice on different days. Values were expressed as mean and SEM of two technical replicates. The plots represent the mean and SEM of two independent experiments.

[0044] Figure 6 is a series of graphs presenting the CV staining of bacterial biofilm from Staphylococcus spp. clinical isolates and upon exposure to Composition A (PHMB 2 g / L), Composition B (PHMB 1 g / L), NAC 20 g / L and Tris-EDTA 1.2 g / L. Biofilms of (A) Burdy, (B) Cookie, (C) Hercules, (D) Rex and (E) Paddy were challenged with Composition A, Composition B, NAC and Tris-EDTA for 24h at 37°C. The plates were washed, and biofilms were heat fixed. Biofilms were stained with CV and CV intensity was recorded at 570 nm using Tecan plate reader. The experiments were conducted in duplicate and repeated twice on different days. Values were expressed as mean and SEM of two technical replicates. The plots represent the mean and SEM of two independent experiments.

[0045] Figure 7 is a series of graphs presenting the growth of biofilm bacteria after exposure to Composition A (PHMB 2 g / L), Composition B (PHMB 1 g / L), NAC 20 g / L and Tris-EDTA 1.2 g / L. Biofilms of (A) B. cepacia, (B) E. coli, (C) P. aeruginosa, (D) S. aureus and (E) S. pseudintermedius were challenged with Composition A, Composition B, NAC and Tris-EDTA for 24h at 37°C. The turbidity was recorded at 620 nm using Tecan plate reader. The experiments were conducted in duplicate and repeated twice on different days. Values were expressed as mean and SEM of two technical replicates. The plots represent the mean and SEM of two independent experiments.

[0046] Figure 8 is a series of graphs showing the impact of Composition A (PHMB 2 g / L), Composition B (PHMB 1 g / L), NAC 20 g / L and Tris-EDTA 1.2 g / L on the biofilm growth of Pseudomonas spp. clinical isolates. Biofilms of (A) Aliza, (B) Bear, (C) Gator, (D) Sam and (E) Wilfred were challenged with Composition A, Composition B, NAC and Tris-EDTA for 24h at 37°C. The turbidity was recorded at 620 nm using Tecan plate reader. The experiments were conducted in duplicate and repeated twice on different days. Values were expressed as mean and SEM of two technical replicates. The plots represent the mean and SEM of two independent experiments.

[0047] Figure 9 is a series of graphs presenting the effect of Composition A (PHMB 2 g / L), Composition B (PHMB 1 g / L), NAC 20 g / L and Tris-EDTA 1.2 g / L on the biofilm growth of Staphylococcus spp. clinical isolates. Biofilms of (A) Burdy, (B) Cookie and (C) Hercules, (D) Rex and (E) Paddy were challenged with Composition A, Composition B, NAC and Tris-EDTA for 24h at 37°C. The turbidity was recorded at 620 nm using Tecan plate reader. The experiments were conducted in duplicate and repeated twice on different days. Values were expressed as mean and SEM of two technical replicates. The plots represent the mean and SEM of two independent experiments.

[0048] Figure 10 is a series of graphs showing the results of a time kill biofilm assay of Compositions A, B and C diluted at 1 / 10 against Klebsiella clinical isolates (clinical isolate 1 (A) and 2 (B)). The Klebsiella isolate was allowed to form a biofilm for 24 hrs and Compositions A, B, C, Tris-EDTA and NAC were added. After each respective contact times,the samples were taken and washed 3x with lx PBS buffer. Biofilm eradication was measured using crystal violet staining and solubilised with 30% acetic acid. OD570 nm was measured using a spectrophotometer.

[0049] Figure 11 is a series of graphs showing the results of a time kill biofilm assay of Compositions A, B and C diluted at 1 / 10 against Proteus clinical isolates (clinical isolate 1 (A) and 2 (B)). The Proteus isolate was allowed to form a biofilm for 24 hrs and Compositions A, B, C, Tris-EDTA and NAC were added. After each respective contact times, the samples were taken and washed 3x with lx PBS buffer. Biofilm eradication was measured using crystal violet staining and solubilised with 30% acetic acid. OD570 nm was measured using a spectrophotometer.

[0050] Figure 12 is a series of graphs showing the effect of Compositions A, B, C, Tris-EDTA and NAC against biofilm and planktonic re-growth of two Klebsiella clinical isolates (clinical isolate 1 (A) and 2 (B)) after 24 h exposure to the test compositions.

[0051] Figure 13 is a series of graphs showing the effect of Compositions A, B, C, Tris-EDTA and NAC against biofilm and planktonic re-growth of two P. mirabilis clinical isolates (clinical isolate 1 (A) and 2 (B)) after 24 h exposure to the test compositions.

[0052] Figure 14 is a series of graphs showing the results of a biofilm assay of Composition B, Tris-EDTA and NAC in different dilutions against a Klebsiella clinical isolate. The Klebsiella isolate was allowed to form a biofilm for 24 hrs and Composition B, Tris- EDTA and NAC were added. After 30 mins (A) and 24 hr (B) contact times, the samples were taken and washed 3x with lx PBS buffer. Biofilm eradication was measured using crystal violet staining and solubilised with 30% acetic acid. OD570 nm was measured using a spectrophotometer.

[0053] Figure 15 is a series of representative graphs showing the percentage killing of Burkholderia species (8. cenocepacia (A and B), 8. cepacia (C and D) and 8. multivorans (E and F)) by Compositions A, B and C, Tris-EDTA and NAC. Compositions A, B and C were diluted into 1 / 5 and 1 / 10 and Tris-EDTA and NAC were diluted into 1 / 2 and 1 / 10. Samples were exposed to Burkholderia species for 10 sec, 30 sec and 60 sec.

[0054] Figure 16 is a series of representative graphs showing the percentage killing of Burkholderia species (8. cenocepacia (A) and 8. multivorans (B)) by Compositions A, B and C at 1 / 10, 1 / 16 and 1 / 32 dilutions. Compositions were exposed to Burkholderia species for 10 sec, 30 sec and 60 sec.

[0055] Figure 17 is a series of representative graphs showing the percentage killing of Burkholderia species (B. cenocepacia (A) and B. multivorans (B)) by Compositions A, B and C with and without parabens included at 1 / 5, 1 / 10, 1 / 16 and 1 / 32 dilutions.These graphs demonstrate that the preservatives do not contribute to the efficacy of the compositions.

[0056] Figure 18 is a representative graph showing the efficacy of Compositions A, B and C in eradicating B. cenocepacia (ATCC BAA-245) biofilms. B. cenocepacia was allowed to form a biofilm for 24 hrs. Compositions A, B and C, Tris-EDTA and NAC were diluted into 1 / 2 and added into the established biofilms. After 24 hrs contact time, the samples were taken and washed 3x with lx PBS buffer. Biofilm eradication was measured using crystal violet staining and solubilised with 30% acetic acid. OD570 nm was measured using a spectrophotometer. The positive control is the biofilm without any treatment.

[0057] Figure 19 is a graph showing the impact of Compositions A, B and C against biofilm and planktonic re-growth of B. cenocepacia ATCC BAA-245 after 24 hr exposure to Compositions A, B and C, Tris-EDTA and NAC. The positive control is the biofilm without any treatment.

[0058] Figure 20 is a representative graph showing the percentage killing of Compositions A, B and C, Tris-EDTA and NAC against S. marcescens for 10 sec, 30 sec and 60 sec.

[0059] Figure 21 is a representative graph showing the percentage killing of Compositions A, B and C, Tris-EDTA and NAC against C. urealyticum (A) and an Enterococcus clinical isolate (B). Samples were diluted into 1 / 10 and exposed to the bacteria for 10 sec, 30 sec and 60 sec.

[0060] Figure 22 is a series of graphs presenting the antibiotic susceptibility of mixed bacterial samples before and after treatment with Composition A and Tris-EDTA. The graphs present the concentration in pg / mL where no growth of bacterial samples was achieved before and after the treatments in the presence of (A) enrofloxacin (B) gentamicin (C) marbofloxacin and (D) neomycin. Values were expressed as mean and SEM.

[0061] Figure 23 is a series of graphs showing the efficacy of Composition B and a Comparator Composition (0.15% chlorhexidine digluconate and Tris-EDTA) in eradicating M. pachydermatis biofilms (M. pachydermatis ATCC 14522 (A) and five clinical isolates (B- F)). Biofilms were challenged with 1 / 2, 1 / 4, 1 / 8, 1 / 16, 1 / 32, 1 / 64 and 1 / 256 of Composition B and the Comparator Composition for 24 hrs at 37°C. The plates were washed, and biofilms were heat fixed. Biofilms were stained with crystal violet and crystal violet intensity was recorded at 570 nm using a Tecan plate reader. The experiments were conducted in triplicate. Values were expressed as mean and standard error of the mean (SEM) of three technical replicates.DETAILED DESCRIPTION OF THE INVENTION1. Definitions

[0062] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the invention belongs. Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, preferred methods and materials are described. For the purposes of the present invention, the following terms are defined below.

[0063] The articles "a" and "an" are used herein to refer to one or to more than one (i.e. to at least one) of the grammatical object of the article. By way of example, "an element" means one element or more than one element.

[0064] By "about" is meant a quantity, level, value, number, frequency, percentage, dimension, size, amount, weight or length that varies by as much 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2 or 1 % to a reference quantity, level, value, number, frequency, percentage, dimension, size, amount, weight or length.

[0065] The terms "administration concurrently," "administered concurrently," "applied concurrently, "contacted concurrently" and the like refer to the administration or application of a single composition containing two or more agents (e.g. the composition of the invention and an antibiotic), or the administration of each agent (e.g. the composition of the invention and an antibiotic) as separate compositions and / or delivered by separate routes contemporaneously, simultaneously or sequentially within a short enough period of time that the effective result is equivalent to that obtained when all such agents are administered or applied as a single composition. By "simultaneously" is meant that the agents are administered or applied at substantially the same time, and desirably together in the same composition. By "contemporaneously" it is meant that the agents are administered or applied closely in time, e.g., one agent is administered or applied within from about one minute to within about one day before or after another. Any contemporaneous time is useful. However, it will often be the case that when not administered or applied simultaneously, the agents will be administered or applied within about one minute to within about eight hours and suitably within less than about one to about four hours. When administered contemporaneously, the agents are suitably administered at the same site on the subject or applied at the same site. The term "same site" includes the exact location, but can be within about 0.5 to about 15 centimetres, preferably from within about 0.5 to about 5 centimetres. The term "separately" as used herein means that the agents are administered or applied at an interval, for example at an interval of about a day to several weeks or months. The agents may be administered or applied in either order. The term "sequentially" as used herein means that the agents areadministered or applied in sequence, for example at an interval or intervals of minutes, hours, days or weeks. If appropriate the agents may be administered or applied in a regular repeating cycle.

[0066] The term "agent" includes a compound or composition (e.g. a composition comprising PHMB or a pharmaceutically or veterinary acceptable salt thereof, a chelating agent and a buffering agent) that induces a desired pharmacological and / or physiological effect. The term also encompasses pharmaceutically or veterinary acceptable and pharmacologically active ingredients of those compounds specifically mentioned herein including but not limited to salts, esters, amides, prodrugs, active metabolites, analogues and the like. When the above term is used, then it is to be understood that this includes the active agent per se as well as pharmaceutically or veterinary acceptable, pharmacologically active salts, solvates, esters, amides, prodrugs, metabolites, analogues, etc. The term "agent" is not to be construed narrowly but extends to small molecules, proteinaceous molecules such as peptides, polypeptides and proteins as well as compositions comprising them and genetic molecules such as RNA, DNA and mimetics and chemical analogues thereof as well as cellular agents, or a composition of the invention.

[0067] The term "alkyl" as used herein as a group or part of a group refers to a straight or branched aliphatic hydrocarbon group, including a Ci-io alkyl, Ci-6 alkyl, C1-5 alkyl, Ci-4 alkyl, C1-3 alkyl and C1-2 alkyl unless otherwise noted. Examples of alkyl groups include methyl, ethyl, propyl, isopropyl, n-butyl, sec butyl, tert-butyl, pentyl, 2- methylpentyl, 3-methylpentyl, n-hexyl, 2-, 3- or 4- methyl hexyl, 2-, 3- or 4-ethylhexyl, heptyl, octyl, nonyl and decyl. In some embodiments, the alkyl group is unbranched (i.e. a straight aliphatic hydrocarbon group). In particular embodiments, an alkyl group may be optionally substituted by 1 to 3 substituents (e.g. 1, 2 or 3 substituents), wherein the substituent is selected from the group consisting of OH, OC1-6 alkyl, Cl, Br, F, I, NH2, NH(Ci- 6 alkyl), N(CI-6 alkyl)2, SH, SC1-6 alkyl, CO2H, CO2C1-6 alkyl, CONH2, CONH(CI-6alkyl) or C0N(Ci-e alkyl)2. In alternative embodiments, the alkyl is unsubstituted.

[0068] As used herein, the term "and / or" refers to and encompasses any and all possible combinations of one or more of the associated listed items, as well as the lack of combinations when interpreted in the alternative (or).

[0069] The terms "antibiotic" and the like when used herein refer to a chemical substance used in medicine that is capable of destroying or weakening, inhibiting or reducing growth of certain microorganisms that cause infections or infectious diseases, especially pathogenic bacteria. Antibiotics may have activity against one or more classes of bacteria, for example, one or both of Gram positive and Gram negative pathogenic bacteria, and find application in the treatment of a wide range of bacterial infections. In some embodiments, antibiotics of the present invention include, but are not limited to,those having obtained marketing authorisation or regulatory approval, and pharmaceutically or veterinary acceptable salts, solvates or in vivo hydrolysable esters thereof.

[0070] The term "aryl" as used herein refers to an unsaturated aromatic carbocyclic group having a single ring (e.g. phenyl) or multiple condensed rings (e.g. naphthyl or anthryl), including from 6-10 carbon atoms (and all integer carbon atoms therebetween). Where multiple rings are present, at least one of the rings is aromatic. Each ring may be, for example, a 6-membered ring. In some embodiments, the aryl group is Ce-io aryl. In particular embodiments, the aryl group is phenyl or naphthyl; especially phenyl. In some embodiments, an aryl group may be optionally substituted by 1 to 3 substituents (e.g. 1, 2 or 3 substituents), wherein the substituent is selected from the group consisting of OH, OCi-6 alkyl, Cl, Br, F, I, NH2, NH(CI-6 alkyl), N(CI-6 a I ky 1)2, SH, SC1-6 alkyl, CO2H, CO2C1-6 alkyl, CONH2, CONH(CI-6 alkyl) or CON(CI-6 alkyl)2. In alternative embodiments, the aryl is unsubstituted.

[0071] The term "associated with" when used in relation to conditions associated with a bacterial or fungal infection in a subject, means that the infection contributes, either directly or indirectly, to the pathogenesis or progression of the condition, including of one or more symptoms of the condition. The infection may, for example, directly lead to the pathogenesis (i.e. development) of the condition or the development of one or more symptoms of the condition. Alternatively or in addition, the infection may result in the progression (i.e. worsening) of the condition or one or more symptoms of the condition.

[0072] The term "biofilm" as used herein refers to a community or matrix of microorganisms formed on either an inert or living surface. These microorganisms are encapsulated in a matrix generally containing proteins, nucleic acids and exopolysaccharides as the main components.

[0073] The term "chelating agent" refers to an agent that is able to sequester or bind to monovalent or polyvalent metal ions. For example, the chelating agent may be any agent that is able to sequester a monovalent or polyvalent metal ion, such as sodium, lithium, rubidium, cesium, calcium, magnesium, barium, cerium, cobalt, copper, iron, manganese, nickel, strontium or zinc.

[0074] Throughout this specification and the claims which follow, unless the context requires otherwise, the word "comprise", and variations such as "comprises" and "comprising", will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps. Thus, the use of the term "comprising" and the like indicates that the listed integers are required or mandatory, but that other integers are optional and may or may not be present. By "consisting of" is meant including, and limited to, whatever follows thephrase "consisting of". Thus, the phrase "consisting of" indicates that the listed elements are required or mandatory, and that no other elements may be present. By "consisting essentially of" is meant including any elements listed after the phrase, and limited to other elements that do not interfere with or contribute to the activity or action specified for the listed elements. Thus, the phrase "consisting essentially of" indicates that the listed elements are required or mandatory, but that other elements are optional and may or may not be present depending upon whether or not they affect the activity or action of the listed elements.

[0075] As used herein, the term "cycloalkyl", refers to cyclic hydrocarbon groups containing from 3 to 8 carbon atoms. Suitable cycloalkyl groups include, but are not limited to, cyclopropyl, cyclobutyl, cyclopentyl and cyclohexyl. In particular embodiments, a cycloalkyl group may be optionally substituted by 1 to 3 substituents (e.g. 1, 2 or 3 substituents), wherein the substituent is selected from the group consisting of OH, OCi-6 alkyl, Cl, Br, F, I, NH2, NH(CI-6alkyl), N(CI-6alkyl)2, SH, SCi-6 alkyl, CO2H, CO2Ci-6alkyl, CONH2, CON H(CI-6 alkyl) or CON(CI-6 alkyl)2. In alternative embodiments, the cycloalkyl is unsubstituted.

[0076] By "effective amount", in the context of treating or inhibiting the development of a condition (e.g. an infection) is meant the administration of an amount of an agent or composition to an individual in need of such treatment or prophylaxis, either in a single dose or as part of a series, that is effective for the prevention of incurring a symptom, holding in check such symptoms, and / or treating existing symptoms, of that condition. The effective amount will vary depending upon the health and physical condition of the individual to be treated, the taxonomic group of individual to be treated, the formulation of the composition, the assessment of the medical or veterinary situation, and other relevant factors. It is expected that the amount will fall in a relatively broad range that can be determined through routine trials. In the context of conferring antibiotic susceptibility to a resistant bacterium, increasing the susceptibility of a bacterium to an antibiotic and disrupting or eradicating a biofilm, an effective amount means an amount that is effective for the stated activity (e.g. conferring susceptibility to at least one antibiotic to a resistant bacterium and the like).

[0077] As used herein, the term "external ear" refers to the pinna or auricle and the auditory canal or meatus of the ear.

[0078] The term "heterocyclyl" as used herein refers to a monocyclic, polycyclic, fused or conjugated cyclic hydrocarbon ring, preferably C3-6, wherein one or more carbon atoms (and where appropriate, hydrogen atoms attached thereto) are replaced by a heteroatom so as to provide a non-aromatic ring. Suitable heteroatoms include O, N and S. Where two or more carbon atoms are replaced, this may be by two or more of the sameheteroatom or by different heteroatoms. Suitable examples of heterocyclyl groups include, but are not limited to, pyrrolidinyl, pyrrolinyl, piperidyl, piperazinyl, morpholino, indolinyl, imidazolidinyl, pyrazolidinyl, thiomorpholino, dioxanyl, tetra hydrofuranyl, tetrahydropyranyl, tetrahydropyrrolyl. In some embodiments, a heterocyclyl group is optionally substituted by 1 to 3 substituents (e.g. 1, 2 or 3 substituents), wherein the substituent is selected from the group consisting of OH, OCi-6 alkyl, Cl, Br, F, I, NH2, NH(Ci- 6 alkyl), N(CI-6 alkyl)2, SH, SC1-6 alkyl, CO2H, CO2C1-6 alkyl, CONH2, CONH(CI-6alkyl) or CON(Ci-e alkyl)2. In alternative embodiments, the heterocyclyl is unsubstituted.

[0079] The term "heteroaryl" as used herein represents an unsaturated aromatic carbocyclic group having a single ring or multiple condensed rings, including from 6-10 carbon atoms (and all integer carbon atoms therebetween), wherein at least one ring is aromatic and contains from 1 to 4 heteroatoms selected from the group consisting of O, N and S. Heteroaryl groups within the scope of this definition include, but are not limited to, acridinyl, carbazolyl, cinnolinyl, quinoxalinyl, pyrrazolyl, indolyl, benzotriazolyl, furanyl, thienyl, benzothienyl, benzofuranyl, quinolinyl, isoquinolinyl, oxazolyl, isoxazolyl, indolyl, pyrazinyl, pyridazinyl, pyridinyl, pyrimidinyl, pyrrolyl, tetrahydroquinoline. In some embodiments, a heteroaryl group is optionally substituted by 1 to 3 substituents (e.g. 1, 2 or 3 substituents), wherein the substituent is selected from the group consisting of OH, OC1-6 alkyl, Cl, Br, F, I, NH2, NH(CI-6alkyl), N(CI-6alkyl)2, SH, SC1-6 alkyl, CO2H, CO2C1-6 alkyl, CONH2, CONH(CI-6 alkyl) or CON(CI-6 alkyl)2. In alternative embodiments, the heteroaryl is unsubstituted.

[0080] The term "increased", "increasing" and the like when used in reference to the level of a substance and / or phenomenon in a first sample relative to a second sample, mean that the quantity of substance and / or phenomenon in the first sample is higher than in the second sample by any amount that is statistically significant using any art-accepted statistical method of analysis. When these terms are used to refer to the action of an agent (e.g. a composition of the invention), the first sample may be a sample in the presence of the agent and the second sample may be a comparative sample without the agent. In one embodiment, the increase may be determined objectively, for example when the antibiotic susceptibility of a bacterium is higher than in an untreated bacterium. In another embodiment, the quantity of substance and / or phenomenon in the first sample is at least 10% higher than the quantity of the same substance and / or phenomenon in a second sample. In another embodiment, the quantity of the substance and / or phenomenon in the first sample is at least 25% higher than the quantity of the same substance and / or phenomenon in a second sample. In yet another embodiment, the quantity of the substance and / or phenomenon in the first sample is at least 50% higher than the quantity of the same substance and / or phenomenon in a second sample.

[0081] As used herein, the phrase "inhibit the development of" refers to a prophylactic treatment which increases the resistance of a subject to developing the disease, disorder or condition (e.g. a bacterial infection) or, in other words, decreases the likelihood that the subject will develop the disease, disorder or condition, as well as a treatment after the disease, disorder or condition has begun in order to reduce or eliminate it altogether or prevent it from becoming worse (e.g. inhibit the infection from spreading).

[0082] The term "optionally substituted" as used throughout the specification denotes that the group may or may not be further substituted with one or more nonhydrogen substituent groups. In particular embodiments, each optionally substituted group may be substituted by 1 to 3 substituents, such as 1, 2 or 3 substituents. In particular embodiments, the substituent is selected from the group consisting of OH, OCi- 6 alkyl, Cl, Br, F, I, NH2, NH(CI-6alkyl), N(CI-6alkyl)2, SH, SCi-6alkyl, CO2H, CO2Ci-6alkyl, CONH2, C0N H(CI-6 alkyl) or CON(CI-6alkyl)2.

[0083] By "pharmaceutically or veterinary acceptable carrier" is meant a pharmaceutical vehicle comprised of a material that is not biologically or otherwise incompatible, i.e., the material may be administered to a subject along with the selected active agents without causing any or a substantial adverse reaction.

[0084] Similarly, a "pharmaceutically or veterinary acceptable" salt, solvate, ester or prodrug of a compound as provided herein is a salt, solvate, ester or prodrug that is not biologically or otherwise incompatible.

[0085] The term "resistant" and grammatical variants thereof are used herein to refer to the capacity of bacteria to withstand the effects of one or more antibiotics present at a concentration that is known in the art to be sufficient to kill or inhibit such bacterial species (i.e. non-resistant species) or has previously killed or inhibited other strains of the same bacterial species.

[0086] As used herein, the terms "salts" and "prodrugs" include any pharmaceutically or veterinary acceptable salt, ester, hydrate or any other compound which, upon administration to the recipient, is capable of providing (directly or indirectly) the specified compound, or an active metabolite or residue thereof. The term "pharmaceutically or veterinary acceptable salts" refers without limitation to derivatives of the disclosed compounds wherein the parent compound is modified by converting an existing acid or base moiety to its salt form (e.g. by reacting the free base group with a suitable organic acid). Examples of pharmaceutically or veterinary acceptable salts include, but are not limited to, mineral or organic acid salts of basic residues such as amines; alkali or organic salts of acidic residues such as carboxylic acids; and the like. Representative acid addition salts include acetate, adipate, alginate, ascorbate, aspartate, benzenesulfonate, benzoate, bisulfate, borate, butyrate, camphorate, camphorsulfonate,citrate, cyclopentanepropionate, digluconate, dodecylsulfate, ethanesulfonate, fumarate, glucoheptonate, glycerophosphate, hemisulfate, heptonate, hexanoate, hydrobromide, hydrochloride, hydroiodide, 2-hydroxy-ethanesulfonate, lactobionate, lactate, laurate, lauryl sulfate, malate, maleate, malonate, methanesulfonate, 2-naphthalenesulfonate, nicotinate, nitrate, oleate, oxalate, palmitate, pamoate, pectinate, persulfate, 3- phenylpropionate, phosphate, picrate, pivalate, propionate, stearate, succinate, sulfate, tartrate, thiocyanate, toluenesulfonate, undecanoate and valerate salts, and the like. Representative alkali or alkaline earth metal salts include sodium, lithium, potassium, calcium, magnesium, and the like, as well as nontoxic ammonium, quaternary ammonium, and amine cations, including, but not limited to ammonium, tetramethylammonium, tetraethylammonium, methylamine, dimethylamine, trimethylamine, triethylamine, ethylamine, and the like. Also included are disodium, trisodium, tetrasodium, dipotassium, tripotassium, dilithium, diammonium and calcium disodium salts. The pharmaceutically or veterinary acceptable salts described herein include the conventional non-toxic salts of the parent compound formed, for example, from non-toxic inorganic or organic acids. The pharmaceutically or veterinary acceptable salt can be synthesised from the parent compound which contains a basic or acidic moiety by conventional chemical methods. Generally, such salts can be prepared by reacting the free acid or base forms of these compounds with a stoichiometric amount of the appropriate base or acid in water or in an organic solvent, or in a mixture of the two; generally, non-aqueous media like ether, ethyl acetate, ethanol, isopropanol, or acetonitrile are preferred. Lists of suitable salts are found in, for example, Remington: The Science and Practice of Pharmacy, Adeboye Adejare and Joseph Remington (Ed), Academic Press, London, 23rdEdition, 2021; Stahl and Wermuth (2002) Pharmaceutical Salts: Properties, Selection, and Use, Wiley-VCH; and Berge et al. (1977) Journal of Pharmaceutical Science, 66: 1-19, each of which is incorporated herein by reference in its entirety.

[0087] The term "susceptibility" as used herein in the context of antibiotic susceptibility (or antibiotic sensitivity) means that the growth of a bacterium is inhibited by an antibiotic. The growth may be inhibited by, for example, at least about 40%, at least about 50%, at least about 60%, at least about 70%, at least about 80%, at least about 90%, at least about 95% or at least about 99% by the antibiotic. In some embodiments, the growth is completely inhibited by the antibiotic.

[0088] The term "subject" as used herein refers to a vertebrate subject, particularly a mammalian subject, for whom therapy or prophylaxis is desired. Suitable subjects include, but are not limited to, primates; avians (birds); livestock animals such as sheep, cows, horses, deer, donkeys and pigs; laboratory test animals such as rabbits, mice, rats, guinea pigs and hamsters; companion animals such as cats and dogs; and captive wild animals such as foxes, deer and dingoes. In some embodiments, the subjectis a primate, suitably a human or a companion animal, such as a cat or dog. In particular embodiments, the subject is a human or a dog. However, it will be understood that the aforementioned terms do not imply that symptoms are present.

[0089] As used herein, the term "tautomer" refers to isomeric forms of a compound which have migration of a hydrogen atom accompanied by movement of adjacent double bonds.

[0090] As used herein, the terms "treatment", "treating", and the like, refer to obtaining a desired pharmacologic and / or physiologic effect. The effect may be therapeutic in terms of a partial or complete cure for a disease, disorder or condition and / or adverse effect attributable to the disease, disorder or condition. These terms also cover any treatment of a condition or disease in a subject, particularly in a human, and include: (a) inhibiting the disease or condition, i.e. arresting or slowing its development; or (b) relieving the disease or condition, i.e. causing regression of the disease or condition.

[0091] Each embodiment described herein is to be applied mutatis mutandis to each and every embodiment unless specifically stated otherwise.2. Abbreviations

[0092] The following abbreviations are used throughout the application:PHMB =poly(hexamethylene) biguanideEDTA =ethylenediamine tetraacetic acidTris =tris(hydroxymethyl)aminomethane NSAID =nonsteroidal anti-inflammatory drug EPS =extracellular polymeric substance NAC =N-acetyl cysteineMBEC =minimal biofilm eradication concentrationMIC =minimal inhibitory concentrationMBC =minimal bactericidal concentration spp. =speciesOD =optical densityCV = crystal violetTSBLT =Tryptic Soy Broth with Lecithin and Tween 80ATCC =American Type Culture Collection h =hour min =Minute TSA =Tryptic soy agar SDB =Sabouraud Dextrose broth SDA =Sabouraud Dextrose agar PBS =phosphate-buffered saline3. Methods

[0093] The inventors have found that a composition comprising PHMB or a pharmaceutically or veterinary acceptable salt thereof, a chelating agent and a buffering agent eradicates and disrupts biofilms, including biofilms formed by bacterial species that are known to be resistant to standard antibiotics or have the potential to develop resistance to standard antibiotics. The inventors have also found that the composition can increase the susceptibility of the bacterium to antibiotics. Based on this activity, the compositions are considered to be useful for disrupting and eradicating biofilms, treating or inhibiting the development of an infection, and / or increasing the susceptibility of bacteria to antibiotics.

[0094] The composition of the invention comprises PHMB or a pharmaceutically or veterinary acceptable salt thereof, a chelating agent and a buffering agent.

[0095] Poly(hexamethylene) biguanide (also known as polyhexanide, polyaminopropyl biguanide or PHMB) has the following formula:or a tautomer thereof, wherein n is an integer from 3 to 500, each y is independently an integer from 1 to 3 and R1and R2are independently selected from H, -NH2, -NH-C(=NH)- NH-CN, -NH-C(=NH)-NH2 optionally substituted alkyl, optionally substituted cycloalkyl, optionally substituted aryl, optionally substituted heterocyclyl and optionally substituted heteroaryl or a pharmaceutically or veterinary acceptable salt thereof. In particular embodiments, n has an average value of 3 to 20 (and all integers in between), 10 to 20, 12 to 16 or 13 to 16. In some embodiments, n is 12, each y is 1 and R1and R2are H. In alternative embodiments, n is 13 to 16. In some embodiments, the compound has a molecular weight of about 2.5 to about 3.1 kDa.

[0096] PHMB is commercially available as Vantocil, Baquacil, Arlagard, Lonzabac BG or Cosmocil. In some embodiments, the salt of PHMB is the hydrochloride salt, which is commercially available from Arxada (Switzerland) under the trademark Cosmocil CQ™ or Cosmocil PGTM.

[0097] The composition may comprise PHMB or a pharmaceutically or veterinary acceptable salt thereof in an amount in the range of from about 0.02% to about 10% w / v (and all one hundredth integer percentages in between), about 0.025% to about 10% w / v, about 0.025% to about 5% w / v, about 0.025% to about 2% w / v, about 0.025% to about 1% w / v, about 0.025% to about 0.5% w / v, about 0.025% to about 0.2% w / v, about0.05% to about 0.2% w / v or about 0.05% to about 0.15% w / v; especially about 0.025% to about 0.2% w / v, about 0.05% to about 0.2% w / v or about 0.05% to about 0.15% w / v. In some embodiments, the composition comprises PHMB or a pharmaceutically or veterinary acceptable salt thereof in an amount of about 0.05%, 0.1%, 0.15%, 0.2% or 0.25%, especially about 0.05%, 0.1% or 0.2% w / v. In some embodiments, the composition comprises PHMB or a pharmaceutically or veterinary acceptable salt thereof in an amount of about 0.05% or 0.1% w / v.

[0098] The chelating agent may be any pharmaceutically or veterinary acceptable chelating agent. Suitable chelating agents include, but are not limited to, an aminopolycarboxylic acid such as glycinate, iminodiacetic acid, nitrilotriacetic acid, nitrilotripropionic acid, ethylenediamine tetraacetic acid (EDTA), diethylenetriamine pentaacetic acid, ethylene glycol-bis(P-aminoethyl ether)- / V, / V, / V', / V'-tetraacetic acid, 1,2- bis(o-aminophenoxy)ethane- / V, / V, / V / , / V / -tetraacetic acid, l,4,7-triazacyclononane-l,4,7- triacetic acid, 2,2',2",2"'-(l,4,7,10-tetraazacyclododecane-l,4,7,10-tetrayl)tetraacetic acid, nicotimamine, ethylenediamine- / V, / V'-bis(2-hydroxyphenylacetic acid), ethylenediamine disuccinic acid, 2-hydroxyethyl-ethylenediamine-triacetic acid, 1,6- diamino-hexamethylene-tetraacetic acid, 1,2-diamino-cyclohexane tetraacetic acid, 0,09- bis(2-aminoethyl)-ethyleneglycol-tetraacetic acid, 1,3-diaminopropane-tetraacetic acid, / V, / V-bis(2-hydroxybenzyl)ethylenediamine- / V, / V-diacetic acid, ethylenediamine- / V, / V9- diacetic acid, ethylenediamine- / V, / V9-dipropionic acid, triethylenetetraamine hexaacetic acid, 7,19,30-trioxa-l,4,10,13,16,22,27,33-octaazabicyclo[ll,ll,ll]pentatriacontane (O-bis-tren), ethylenediamine- / V, / V9-bis(methylenephosphonic acid), iminodiacetic acid, / V, / V-bis(2-hydroxyethyl)glycine, l,3-diamino-2-hydroxypropane-tetraacetic acid, 1,2- diaminopropane-tetraacetic acid, ethylenediamine-tetrakis(methylenephosphonic acid), N- (2-hydroxyethyl)iminodiacetic acid or triethylenetetramine-hexaacetic acid; deferoxamine, dimercaprol; citrate (e.g. zinc citrate); penicillamine; a bisphosphonate such as etidronate; a macrocyclic polyether; polyaspartic acid; methylglycinediacetic acid; glutamic diacetic acid; gluconic acid; or a pharmaceutically or veterinary acceptable salt or combination of any of the foregoing. In particular embodiments, the chelating agent is EDTA or a pharmaceutically or veterinary acceptable salt thereof.

[0099] In some embodiments, EDTA is in the form of a pharmaceutically or veterinary acceptable salt, such as a disodium, trisodium, tetrasodium, dipotassium, tripotassium, lithium, dilithium, ammonium, diammonium or calcium disodium salt. In particular embodiments, the salt is the disodium salt.[O1OO] The composition may comprise the chelating agent in an amount in the range of from about 0.01% to about 5% w / v (and all one hundredth integer percentages in between), about 0.05% to about 2% w / v, about 0.05% to about 1% w / v, about 0.05% to about 0.5% w / v, about 0.1% to about 0.2% w / v or about 0.1% to about 0.15% w / v.In some embodiments, the composition comprises the chelating agent in an amount of about 0.1%, 0.11%, 0.12%, 0.13%, 0.14% or 0.15% w / v; especially about 0.12% w / v.[O1O1] In some embodiments, the composition comprises PHMB or a pharmaceutically or veterinary acceptable salt thereof and the chelating agent in a weight ratio of from about 3: 1 to about 1 : 10, about 2: 1 to about 1 :4, about 1.7: 1 to about 1:4, about 1.7: 1 to about 1:2.4, about 1: 1 to about 1:4, about 1 : 1 to about 1 :3, about 1: 1 to about 1:2.5 or about 1 : 1.2 to about 1 :2.4. In some embodiments, the composition comprises PHMB or a pharmaceutically or veterinary acceptable salt thereof and the chelating agent in a weight ratio of about 1.7: 1, 1 : 1.2 or 1:2.4.

[0102] The buffering agent may be any pharmaceutically or veterinary acceptable buffering agent. Suitable buffering agents include, but are not limited to, tris(hydroxymethyl)aminomethane (Tris), triethylamine, triethylenetetramine, tetraethylethylenediamine, tetramethylenediamine, / V, / V'-diethyl- / V, / V'-bis(sulfopropyl)- ethylenediamine, / V, / V'-diethylpiperazine, piperazine- / V, / V'-bis(alkylsulfonic acids), ( / V-morpholino)alkylsulfonic acids (e.g. 2-morpholineethanesulfonic acid or 4- morpholinepropane sulfonic acid), 2-aminoethanol, 2-amino-2-methyl-l-propanol, triethanolamine, 2-amino-2-methyl-l,3-propanediol, bis-(2-hydroxyethyl)imino- tris(hydroxymethyl)methane, 2-dimethylamino-2-methyl-l-propanol, 2-amino-2-ethyl- 1,3-propanediol, l,3-bis(tris[hydroxymethyl]methylamino)propane, / V, / V-bis(2- hydroxyethyl)-2-aminoethanesulfonic acid, / V-[tris(hydroxymethyl)methyl]-3- aminopropanesulfonic acid, / V, / V-bis(2-hydroxyethyl)glycine, / V, / V-bis(2- hydroxyethyl)taurine, diethanolamine, / V-tris(hydroxymethyl)methylglycine, 2,2 bis(hydroxymethyl)-2,29,20-nitrilotriethanol, 1,3 bis(tris[hydroxymethyl]methylamino)propane, acetic acid, adipic acid, ammonia solution, ammonium phosphate, ammonium sulfate, arginine, asparagine, boric acid, calcium carbonate, calcium lactate, calcium phosphate, tribasic, citric acid monohydrate, dibasic potassium phosphate, dibasic sodium phosphate, glycine, histidine, hydroxyethylpiperazine ethane sulfonic acid, lysine acetate, lysine hydrochloride, maleic acid, malic acid, meglumine, methionine, monobasic sodium phosphate, monoethanolamine, monosodium glutamate, phosphoric acid, potassium citrate, potassium metaphosphate, sodium acetate, sodium bicarbonate, sodium bisulfate, sodium borate, sodium carbonate, sodium chloride, sodium citrate dihydrate, sodium lactate, tromethamine or a pharmaceutically or veterinary acceptable salt or combination of any of the foregoing. In particular embodiments, the buffering agent is tris(hydroxymethyl)aminomethane (Tris), triethylamine, triethylenetetramine, tetraethylethylenediamine, tetramethylenediamine, / V, / V'-diethyl- / V, / V'-bis(sulfopropyl)- ethylenediamine, / V, / V'-diethylpiperazine, piperazine- / V, / V'-bis(alkylsulfonic acids), ( / V-morpholino)alkylsulfonic acids, 2-aminoethanol, 2-amino-2-methyl-l-propanol,triethanolamine, 2-amino-2-methyl-l,3-propanediol, bis-(2-hydroxyethyl)imino- tris(hydroxymethyl)methane, 2-dimethylamino-2-methyl-l-propanol, 2-amino-2-ethyl- 1,3-propanediol, l,3-bis(tris[hydroxymethyl]methylamino)propane, / V, / V-bis(2- hydroxyethyl)-2-aminoethanesulfonic acid, / V-[tris(hydroxymethyl)methyl]-3- aminopropanesulfonic acid, / V, / V-bis(2-hydroxyethyl)glycine, / V, / V-bis(2- hydroxyethyl)taurine, diethanolamine, / V-tris(hydroxymethyl)methylglycine or a pharmaceutically or veterinary acceptable salt or combination of any of the foregoing. In specific embodiments, the buffering agent is Tris or a pharmaceutically or veterinary acceptable salt thereof, such as Tris hydrochloride salt. In some embodiments, the composition comprises Tris and Tris hydrochloride salt.

[0103] The buffering agent may be present in an amount sufficient to provide the composition with a suitable pH, such as a pH between 3 and 9. For example, in some embodiments, the composition comprises the buffering agent in an amount in the range of from about 0.01% to about 5% w / v (and all one hundredth integer percentages in between), about 0.05% to about 2% w / v, about 0.1% to about 1% w / v, about 0.3% to about 0.9% w / v, about 0.5% w / v to about 0.8% w / v, or about 0.6% to about 0.8% w / v. In particular embodiments, the composition comprises the buffering agent in an amount in the range of from about 0.5%, 0.6%, 0.605%, 0.61%, 0.62%, 0.63%, 0.64%, 0.65%, 0.66%, 0.67%, 0.68%, 0.69%, 0.7%, 0.71%, 0.72%, 0.73%, 0.74%, 0.75%, 0.757%, 0.76%, 0.77%, 0.78%, 0.79% or 0.8% w / v.

[0104] In some embodiments, the composition comprises Tris in an amount of about 0.1% w / v and Tris hydrochloride salt in an amount of about 0.657% w / v.

[0105] In some embodiments, the composition is buffered between pH 3 to 9, such as between pH 5 to 8 (and all one tenth integers in between). In some embodiments, the pH is between pH 6 and 8, such as between pH 6 and 7. In particular embodiments, the pH is about pH 6, 6.5, 7, 7.5 or 8.

[0106] If required, the composition may further comprise a pH adjusting agent, such as ammonia solution, diethanolamine, meglumine, sodium citrate dihydrate, sodium hydroxide, sodium phosphate, sodium borate, sodium citrate, sodium acetate, sodium lactate, tromethamine, hydrochloric acid, trishydroxymethylamino-methane or a combination thereof.

[0107] In some embodiments, the composition comprises PHMB or a pharmaceutically or veterinary acceptable salt thereof and the buffering agent in a weight ratio of from about 1 : 1 to about 1:20 (and all one tenth integer ratios in between), about 1 :2 to about 1: 17, about 1 :3 to about 1 : 16, about 1:5 to about 1: 16 or about 1:7 to about 1 : 15. In some embodiments, the composition comprises PHMB or a pharmaceutically or veterinary acceptable salt thereof and the buffering agent in a weight ratio of from about1:2 to about 1:5, about 1:3 to about 1:4, about 1:6 to about 1:9, about 1:7 to about 1:8, about 1:14 to about 1:17 or about 1:15 to about 1:16. In some embodiments, the composition comprises PHMB or a pharmaceutically or veterinary acceptable salt thereof and the buffering agent in a weight ratio of about 1:2, 1:2.5 1:3, 1:3.1, 1:3.2, 1:3.3, 1:3.4, 1:3.5, 1:3.6, 1:3.7, 1:3.8, 1:3.9, 1:4, 1:4.1, 1:4.2, 1:4.3, 1:4.4, 1:4.5, 1:5, 1:5.5, 1:6, 1:6.5, 1:7, 1:7.1, 1:7.2, 1:7.3, 1:7.4, 1:7.5, 1:7.6, 1:7.7, 1:7.8, 1:7.9, 1:8, 1:8.5, 1:9, 1:9.5, 1:10, 1:10.5, 1:11, 1:11.5, 1:12, 1:12.5, 1:13, 1:13.5, 1:14, 1:14.5, 1:14.8, 1:14.9, 1:15, 1:15.1, 1:15.2, 1:15.3, 1:15.4, 1:15.5, 1:15.6, 1:15.7, 1:15.8, 1:16, 1:16.5, 1:17, 1:18, 1:19 or 1:20, such as about 1:3.8, about 1:7.6 or about 1:15.2.

[0108] In some embodiments, the composition comprises the chelating agent and the buffering agent in a weight ratio of from about 1 : 1 to about 1 : 12 (and all one tenth integer ratios in between), about 1:2 to about 1:11, about 1:3 to about 1:10, about 1:4 to about 1:9, about 1:5 to about 1:8 or about 1:6 to about 1:7. In some embodiments, the composition comprises the chelating agent and the buffering agent in a weight ratio of about 1:1, 1:2, 1:3, 1:4, 1:5, 1:5.5, 1:6, 1:6.1, 1:6.2, 1:6.3, 1:6.4, 1:6.5, 1:6.6, 1:6.7, 1:6.8, 1:6.9, 1:7, 1:7.5, 1:8, 1:9, 1:10, 1:11 or 1:12. In particular embodiments, the composition comprises the chelating agent and the buffering agent in a weight ratio of about 1:6, 1:6.1, 1:6.2, 1:6.3, 1:6.4, 1:6.5, 1:6.6, 1:6.7, 1:6.8, 1:6.9 or 1:7, such as about 1:6.3.

[0109] In some embodiments, the composition further comprises a rheology modifier. Suitable rheology modifiers include, but are not limited to, propylene glycol, polyethylene glycol, polypropylene glycol(s), ethylene glycol palmitostearate, bentonite, celluloses such as methylcellulose, ethylcellulose, carboxymethylcellulose, hydroxypropylmethylcellulose, hydroxyethylcellulose, hydroxyethyl methyl cellulose or hydroxypropylcellulose, acrylates / beheneth-25 methacrylate copolymer, tragacanth, gum arabic, xanthan gum, guar gum, locust bean gum, alginate, starch (e.g. from rice, corn, potato or wheat), modified starch, carrageenan, konjac, aloe vera gel, agarose, pectin, curdlan gum, gellan gum, scleroglucan, hyaluronic acid, chitosan-polyvinyl alcohol or derivatives thereof, chitosan, chitins, heparans, dermatans, chrondroitins, heparins, polyvinyl alcohol, polyvinyl pyrrolidone, carbopol or derivatives thereof, dextran, dextrin, hydroxypropyl guar, agar, aliphatic polyesters, aluminum monostearate, ammonium alginate, ceratonia, colloidal silicon dioxide, gelatin, glyceryl monooleate, glyceryl palmitostearate, polycarbophil, polyethylene alkyl ethers, polyethylene oxide, polymethacrylates, polyoxyethylene alkyl ethers, potassium alginate, potassium chloride, sodium ascorbate, sodium stearate, sorbitol, zinc acetate, zinc stearate, alginic acid, ammonium alginate, carbomers, ceresin, hectorite, / V-isopropyl acrylamide, sodium acrylate, / V- / V-alkylacrylamide, ammonium sulfate, attapulgite, betadex sulfobutyl ether sodium, calcium alginate, calcium lactate, cellulose acetate hydrogen phthalate latex,cetostearyl alcohol, cetyl palmitate, corn syrup solids, cyclomethicone, dextrin, glycerin, glyceryl behenate, glyceryl laurate, hydrogenated palm oil, hydrogenated vegetable oil type I, hydrophobic colloidal silica, karaya gum, magnesium aluminum silicate, maltodextrin, myristyl alcohol, octyldodecanol, poloxamer, a poloxamine, polydextrose, cross-linked polyacrylic acid, polyacrylic acid with polyethylene glycol, polymethacrylic acid with polyethylene glycol, poly(methylvinyl ether / maleic anhydride), polyoxyethylene alkyl ethers, polyvinyl methyl ether, propylene glycol alginate, propylene glycol dilaurate, pullulan, saponite, sodium alginate, stearic acid, stearyl alcohol, sucrose, tragacanth, trehalose or a pharmaceutically or veterinary acceptable salt or combination of any of the foregoing. In particular embodiments, the rheology modifier is propylene glycol, polyethylene glycol or a polypropylene glycol; particularly propylene glycol.

[0110] The rheology modifier may be present in an amount which provides a suitable viscosity for the desired route of administration. For example, the rheology modifier may be present in an amount in the range of from about 0.05% to about 20% w / v (and all one hundredth integer percentages in between), about 0.1% to about 15% w / v, about 1% to about 10% w / v, about 2% to about 8% w / v, about 3% to about 7% w / v or about 4% to about 6% w / v. In some embodiments, the rheology modifier is present in an amount of about 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9% or 10% w / v; especially about 5% w / v.[Olli] In some embodiments, the composition further comprises a carrier. As will be appreciated by those skilled in the art, the choice of pharmaceutically or veterinary acceptable carrier will be dependent on the route of administration, the nature of the condition and subject to be treated and the use of the composition. The particular carrier and route of administration may be readily determined by a person skilled in the art. For example, techniques for formulation and administration may be found in, for example, Remington: The Science and Practice of Pharmacy, Adeboye Adejare and Joseph Remington (Ed), Academic Press, London, 23rdEdition, 2021, and Katdare and Chaubel (2006) Excipient Development for Pharmaceutical, Biotechnology and Drug Delivery Systems (CRC Press).

[0112] In some embodiments, the carrier is a liquid carrier, such as an aqueous carrier, glycerol, an oil, an alcohol or a combination thereof. Representative aqueous carriers include water and saline. In some embodiments, the aqueous carrier is water.

[0113] When saline is used as a carrier, the saline comprises, for example, about 0.15% to about 8% (and all one hundredth integer percentages in between), about 0.18% to about 7%, about 0.22% to about 5%, about 0.45% to about 3%, about 0.5% to about 2% or about 0.65% to about 1.5% w / v sodium chloride; especially about 0.9% w / v sodium chloride.

[0114] In some embodiments, the carrier comprises an oil, such as almond oil, canola oil, castor oil, corn oil (maize), cottonseed oil, decyl oleate, ethyl oleate, isopropyl myristate, isopropyl palmitate, light mineral oil, mineral oil, myristyl alcohol, olive oil, peanut oil, propylene glycol dilaurate, propylene glycol monolaurate, safflower oil, sesame oil, soybean oil, oleic acid, sunflower oil, caproic acid (hexanoic acid), enanthic acid (heptanic acid), capric acid (octanoic acid), pelargonic acid (nonanoic acid), caproic acid (decanoic acid), undecilenic acid (undeca-10-enoic acid), jojoba oil, argan oil, tea tree oil, lauric acid (dodecanoic acid) or a combination thereof.

[0115] The carrier may comprise an alcohol, such as isopropanol, benzyl alcohol, cetearyl alcohol, ethanol or a combination thereof.

[0116] In some embodiments, the composition further comprises a preservative. Suitable preservatives include, but are not limited to, methyl hydroxybenzoate (methylparaben), ethyl hydroxybenzoate, propyl 4-hydroxybenzoate (propylparaben), acetic acid, chlorocresol, diazolidinyl urea, dimethyl sulfoxide, imidurea, iodine / edetic acid, phenylmercuric acetate, phenylmercuric borate, phenylmercuric hydroxide, potassium sorbate, sodium hydroxide, sorbic acid, thymol, acetone sodium bisulfite, butylparaben, coconut oil, ethylparaben, sodium propionate, sporocides, vanillin, acetone sodium bisulfite, benzalkonium chloride, benzethonium chloride, benzoic acid, benzyl alcohol, benzyl benzoate, betadex sulfobutyl ether sodium, boric acid, bronopol, butylated hydroxyanisole, butylene glycol, calcium acetate, calcium chloride, calcium lactate, cetrimide, cetrimonium bromide, cetyl pyridinium chloride, chlorhexidine, chlorobutanol, chloroxylenol, chlorphenesin, cresol, hexetidine, hydrogen peroxide, iodopropynyl butylcarbamate, isopropyl alcohol, monothioglycerol, pentetic acid, phenoxyethanol, phenylethyl alcohol, phenylmercuric nitrate, phosphoric acid, potassium metabisulfite, potassium nitrate, povidone-iodine, propyl gallate, propylparaben sodium, sodium acetate, sodium benzoate, sodium metabisulfite, sodium sulfite, tetrasodium edetate, zinc oxide, dimethyl ether, lactic acid, phenol, propionic acid, sodium borate, sodium lactate, thimerosal, or a pharmaceutically or veterinary acceptable salt or combination of any of the foregoing. In some embodiments, the preservative is methyl hydroxybenzoate, propyl 4-hydroxybenzoate, phenoxyethanol, chlorphenesin or a combination thereof. In particular embodiments, the preservative is methyl hydroxybenzoate, propyl 4- hydroxybenzoate or a combination thereof.

[0117] The preservative may be present, for example, in an amount in the range of about 0.01% to about 5% w / v (and all one hundredth integer percentages in between), about 0.015% to about 2% w / v, about 0.05% to about 2% w / v, about 0.05% to about 1% w / v, about 0.05% to about 0.5% w / v, about 0.1% to about 0.2% w / v or about 0.1% to about 0.15% w / v. In some embodiments, the composition comprises a preservative in anamount of about 0.1%, 0.11%, 0.12%, 0.13%, 0.14% or 0.15% w / v; especially about 0.13% w / v.

[0118] In particular embodiments, the composition comprises methyl hydroxybenzoate in an amount of about 0.1% w / v and propyl 4-hydroxybenzoate in an amount of about 0.03% w / v.

[0119] The composition may further comprise a non-ionic, cationic or amphoteric surfactant, or a combination thereof. Suitable non-ionic surfactants include, but are not limited to, Agridex (polyol fatty acid esters and polyethoxylated polyol fatty acid ester), alkyl polyglucosides, alkyl polyglycoside, fatty acid alkoxylates, decyl glucoside, decyl polyglucose, octyl glucoside, lauryl glucoside, n-dodecyl-p-maltoside, n-octyl-p-D- thioglucopyranoside, alkyl phenol ethoxylates, alpha tocopherol, cetostearyl alcohol, cetyl alcohol, cocamide diethanolamine, cocamide monoethanolamine, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, digitonin, emulsifying wax, fatty alcohol ethoxylates, glyceryl laurate, glyceryl monooleate, glycerol monostearate, IGEPAL CA-630 (octylphenoxy poly(ethyleneoxy)ethanol, branched), isoceteth-20, lauryl glucoside, lauramide monoethylamine, lauramide diethylamine, maltoside, monolaurin, myristyl alcohol, narrow-range ethoxylate, nonidet P-40 (octylphenoxypolyethoxyethanol), nonoxynol-9 (26-(4-nonylphenoxy)-3,6,9,12,15,18,21,24-nonaoxahexacosan-l-ol), nonoxynols, NP-40 (nonyl phenoxypolyethoxylethanol), oleic acid, octaethylene glycol monododecyl ether, N-octyl p-D-thioglucopyranoside, octyl glucoside, oleyl alcohol, phospholipids, pluronics, polyglycols, polyoxyethylene alkyl ethers, polyoxyethylene castor oil derivatives, polyoxyethylene sorbitan fatty acid esters, sorbitan monooleate, polyoxyethylene stearates, polyoxyl 15 hydroxystearate, polyoxylglycerides (e.g. Labrasol), polysorbate 20 (Tween 20), polysorbate 60 (Tween 60), polysorbate 80 (Tween 80), propylene glycol dilaurate, propylene glycol monolaurate, sorbitan esters, sucrose palmitate, sucrose stearate, tricaprylin, vitamin E polyethylene glycol succinate, block copolymers comprising ethylene oxide and propylene oxide, POE 20 cetylstearyl ethers such as Procol (cetearyl alcohol and polysorbate 60 and PEG 150-stearate and steareth- 20), poloxamers (polyoxyethylene / polyoxypropylene surfactants) such as Pluronic F-68, Pluronic F-84, poloxamer 407, poloxamer 188 and Pluronic P-103, Triton X-series surfactants such as Triton X-100 and Triton X-405, tyloxapol, Zonyl FSO, alkylethers of glycerol such as glycerol monolaurate, 2-dimethylaminoethanol, polyethoxylated tallow amine, n-dodecyl-p-D-maltoside, n-octyl-p-D-thioglucopyranoside, octyl glucoside, decyl glucoside, lauryl glucoside, digitonin, pentaethylene glycol monododecyl ether, polidocanol, polyethylene glycol cetyl ether, polyglycerol polyricinoleate, sorbitan, sorbitan monolaurate, sorbitan monostearate, sorbitan tristearate, stearyl alcohol, betaines such as cocamidopropyl betaine and combinations thereof. In some embodiments, the non-ionic surfactant is alkyl polyglycoside, cetostearyl alcohol, cetyl alcohol, cocamidediethanolamine, cocamide monoethanolamine, decyl glucoside, decyl polyglucose, glycerol monostearate, polysorbate 80, cocamidopropyl betaine, polyoxylglycerides or a combination thereof. In some embodiments, the non-ionic surfactant is alkyl polyglycoside, cetostearyl alcohol, cetyl alcohol, cocamide diethanolamine, cocamide monoethanolamine, decyl glucoside, decyl polyglucose, glycerol monostearate or a combination thereof. In some embodiments, the non-ionic surfactant is decyl glucoside, polysorbate 80, cocamidopropyl betaine, polyoxylglycerides or a combination thereof. In particular embodiments, the non-ionic surfactant is decyl glucoside, polysorbate 80, cocamidopropyl betaine or a combination thereof.

[0120] Suitable cationic surfactants include, but are not limited to, benzalkonium chloride, benzethonium chloride, cetrimide, a certrimonium salt such as cetrimonium bromide or cetrimonium chloride, cetylpyridinium chloride, phospholipids, chlorhexidine, quaternary ammonium salts, polyoxyethylene alkyl & alicyclic amines, N,N,N',N' tetrakis substituted ethylenediamines, 2-alkyl-l-hydroxethyl-2-imidazolines and combinations thereof. In some embodiments, the surfactant is a certrimonium salt.

[0121] Suitable amphoteric surfactants include, but are not limited to, / V-coco-3- aminopropionic acid / sodium salt, / V-tallow-3-iminodipropionate, disodium salt, oleyl betaine, / V-cocoamidethyl- / V-hydroxyethylglycine, sodium salt and combinations thereof.

[0122] In particular embodiments, the surfactant is a non-ionic surfactant, particularly decyl glucoside and / or cocamidopropyl betaine. In particular embodiments, the surfactant is cocamidopropyl betaine. In alternative embodiments, the surfactant is certrimonium salts and / or polyoxylglycxerides.

[0123] The surfactant will generally be present at a concentration of about 0.001% to about 5% w / v (and all one thousandth integer percentages in between), about 0.005% to about 2% w / v, about 0.008% to about 1% w / v, about 0.01% to about 0.5% w / v, about 0.01% to about 0.25%, about 0.01% to about 0.1% w / v, about 0.01% to about 0.05% or about 0.01% to about 0.02% w / v. In some embodiments, the composition comprises a surfactant in an amount of about 0.005%, 0.01%, 0.011%, 0.012%, 0.013%, 0.014%, 0.015%, 0.016%, 0.017%, 0.018%, 0.019%, 0.02% or 0.025% w / v. In particular embodiments, the composition comprises a surfactant in an amount of about 0.015% w / v.

[0124] The composition may further comprise an antioxidant, suitable representatives of which include acetone sodium bisulfite, alpha tocopherol, ascorbic acid, ascorbyl palmitate, butylated hydroxyanisole, butylated hydroxytoluene, citric acid monohydrate, dodecyl gallate, erythorbic acid, ethyl oleate, fumaric acid, histidine, malic acid, D-mannose, monothioglycerol, niacinamide, octyl gallate, phosphoric acid, potassium metabisulfite, propionic acid, propyl gallate, sodium ascorbate, sodium bisulfite, sodiumformaldehyde sulfoxylate, sodium metabisulfite, sodium sulfite, sodium thiosulfate, sulfur dioxide, citric acid monohydrate, tartaric acid, thymol, tocopherol polyethylene glycol succinate, tocopherol, ubiquinone, idebenone, lycopene, resveratrol, niacinamide, or a pharmaceutically or veterinary acceptable salt or combination of any of the foregoing.

[0125] The composition may further comprise an acidulant such as acetic acid, acrylic acid, adipic acid, ammonium chloride, ascorbic acid, boric, citric acid monohydrate, phenylacrylic acid (cinnamic acid), coumaric acid (o-hydroxycinnamic acid), fumaric acid, gluconolactone, glycolic acid, hydrochloric acid, hyaluronic acid, lactic acid, maleic acid, malic acid, monobasic sodium phosphate, phosphoric acid, propionic acid, salicyclic acid, acetyl salicylic acid, sorbic acid, sulfuric acid, tartaric acid, umbellic acid (p- hydroxycou marie acid) or a pharmaceutically or veterinary acceptable salt or combination of any of the foregoing; an alkalising agent such as ammonia solution, calcium hydroxide, diethanolamine, monoethanolamine, potassium bicarbonate, potassium citrate, potassium hydroxide, sodium bicarbonate, sodium borate, sodium carbonate, sodium citrate dihydrate, sodium hydroxide, triethanolamine, tromethamine or a pharmaceutically or veterinary acceptable salt or combination of any of the foregoing; a complexing agent such as calcium acetate, cholestyramine resin, citric acid monohydrate, a cyclodextrin (e.g. o- cyclodextrin, p-cyclodextrin, y-cyclodextrin, 2-hydroxypropyl-p-cyclodextrin, hydroxyethyl-p-cyclodextrin, sulfobutylether p-cyclodextrin sodium salt, methylated p- cyclodextrin, dimethyl-p-cyclodextrin, trimethyl-p-cyclodextrin and 2-hydroxypropyl-y- cyclodextrin), dibasic sodium phosphate, edetate calcium disodium, fumaric acid, galactose, gelatin, gluconolactone, maltol, monobasic sodium phosphate, phosphoric acid, polacrilin potassium, polacrilin resin, poly(methylvinyl ether / maleic anhydride), potassium citrate, sodium citrate dihydrate, sodium polystyrene sulfonate, tartaric acid, trehalose or a pharmaceutically or veterinary acceptable salt or combination of any of the foregoing; an emollient such as almond oil, aluminum monostearate, butyl stearate, canola oil, castor oil, a ceramide, ceratonia extract, cetostearyl alcohol, cetyl alcohol, cetyl esters wax, cetyl palmitate, cholesterol, coconut oil, cyclomethicone, decyl oleate, dibutyl sebacate, diethyl sebacate, dimethicone, ethylene glycol palmitostearate, glycerin, glyceryl laurate, glyceryl monooleate, glyceryl monostearate, isopropyl isostearate, isopropyl myristate, isopropyl palmitate, isopropyl stearate, lanolin, hydrous, lanolin alcohols, lecithin, light mineral oil, medium-chain triglycerides, mineral oil, mineral oil and lanolin alcohols, myristyl alcohol, octyldodecanol, oleyl alcohol, palm kernel oil, palm oil, petrolatum, petrolatum or lanolin alcohols, polyoxyethylene sorbitan fatty acid esters, propylene glycol dilaurate, propylene glycol monolaurate, safflower glycerides, safflower oil, soybean oil, squalane, stearyl alcohol, sunflower oil, tricaprylin, triolein, xylitol, zinc acetate or a pharmaceutically or veterinary acceptable salt or combination of any of the foregoing; an organoleptic agent, such as a flavouring agent, fragrance, sweetening agent or colouring agent; a film-formingagent such as ammonium alginate, cellaburate, chitosan, colophony, copovidone, ethylcellulose, ethylene glycol and vinyl alcohol grafted copolymer, gelatin, hydroxyethyl cellulose, hydroxypropyl cellulose, hypromellose, hypromellose acetate succinate, maleic acid, maltodextrin, opacifiers, calcium carbonate, polydextrose, polyethylene glycol, polyethylene oxide, polymethacrylates, polyfmethylvinyl ether / maleic anhydride), polyvinyl acetate dispersion, polyvinyl acetate phthalate, povidone, pullulan, pyroxylin, shellac, triethyl citrate, vanillin or a pharmaceutically or veterinary acceptable salt or combination of any of the foregoing; a humectant such as ammonium alginate, butylene glycol, corn syrup solids, cyclomethicone, dipropylene glycol, glycerin, polydextrose, propylene glycol, sodium hyaluronate, sodium lactate, sorbitol, tagatose, trehalose, triacetin, triethanolamine, xylitol or a pharmaceutically or veterinary acceptable salt or combination of any of the foregoing; a dispersant such as dimyristylphosphatidylcholine, egg-derived natural phosphatidylcholine, egg-derived natural phosphatidylglycerol, cholesterol, isopropyl myristate or a pharmaceutically or veterinary acceptable salt or combination of any of the foregoing; a hygroscopic agent such as fructose, phthalic acid, sorbitol or a pharmaceutically or veterinary acceptable salt or combination of any of the foregoing; a lubricant such as canola oil, dipropylene glycol, glycerin, octyldodecanol, polyvinyl alcohol, sodium hyaluronate, talc, tricaprylin or a pharmaceutically or veterinary acceptable salt or combination of any of the foregoing; a modified-release agent such as gum arabic, acetyltributyl citrate, acetyltriethyl citrate, adipic acid, agar, alginic acid, aliphatic polyesters, bentonite, betadex sulfobutyl ether sodium, biodegradable polymers, calcium alginate, calcium polycarbophil, carbomers, carrageenan, cellaburate, cellulose acetate, cellulose acetate phthalate with ethyl cellulose, ceratonia, cetyl alcohol, cetyl esters wax, chitosan, cholestyramine resin, colophony, copovidone, dimethyl-p- cyclodextrin, ethylcellulose, gellan gum, glyceryl behenate, glyceryl monooleate, glyceryl monostearate, glyceryl palmitostearate, guar gum, hydrogenated castor oil, hydrogenated vegetable oil type I, hydroxpropyl betadex, hydroxyethyl-P-cyclodextrin, hydroxypropyl cellulose, hypromellose, hypromellose acetate succinate, isopropyl palmitate, magnesium aluminum silicate, magnesium oxide, methylcellulose, microcrystalline wax, modified starch, paraffin, peanut oil, polacrilin potassium, polacrilin resin, polycarbophil, polyethylene oxide, poly-DL-(lactic acid), polymethacrylates, polyoxylglycerides, polyvinyl acetate dispersion, potassium chloride, povidone, sesame oil, shellac, sodium bicarbonate, sodium chloride, sodium hyaluronate, sodium lauryl sulfate, sodium polystyrene sulfonate, sodium stearate, stearic acid, sucrose stearate, talc, tributyl citrate, urethane hydrogels, white wax, xanthan gum, yellow wax, zein or a pharmaceutically or veterinary acceptable salt or combination of any of the foregoing; an ointment base such as coconut oil, lanolin hydrous, lanolin alcohols, paraffin, petrolatum, petrolatum and lanolin alcohols, poloxamer, polyethylene glycol, squalane, stearic acid, tocopherol polyethylene glycol succinate or a pharmaceutically or veterinary acceptable salt or combination of any of the foregoing; anopacifier such as aluminum monostearate, calcium carbonate, calcium silicate, ceresin, colouring agent, ethylene glycol palmitostearate, octyldodecanol, titanium oxide, zinc acetate, zinc oxide, zinc stearate or a pharmaceutically or veterinary acceptable salt or combination of any of the foregoing; a permeability enhancer such as an alcohol, benzalkonium chloride, cetylpyridinium chloride, diethyl sebacate, diethylene glycol, dimethyl sulfoxide, ethanol, glyceryl monooleate, glycofurol, hydroxpropyl betadex, isopropyl myristate, isopropyl palmitate, lauric acid, light mineral oil, linoleic acid, menthol, methylpyrrolidone, myristic acid, oleic acid, oleyl alcohol, palmitic acid, polyols, polyoxyethylene alkyl ethers, polyoxylglycerides, propylene glycol dilaurate, propylene glycol monolaurate, pyrrolidone, polyvinyl pyrrolidone, sodium lauryl sulfate, squalane, thymol, tricaprylin, triolein or a pharmaceutically or veterinary acceptable salt or combination of any of the foregoing; a solubilising agent or wetting agent such as an alkanol, anionic emulsifying wax, benzalkonium chloride, benzethonium chloride, benzyl alcohol, benzyl benzoate, betadex sulfobutyl ether sodium, bile salt, cetylpyridinium chloride, cholesterol, cholestyramine resin, a cyclodextrin, diethylene glycol, dimethylacetamide, dimethylisosorbide, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, ethyl oleate, ethyl caprylate, fumaric acid, glyceryl laurate, glyceryl monostearate, glycoflor, hydroxpropyl betadex, hydroxyethyl-p-cyclodextrin, hypromellose, isopropyl alcohol, lanolin alcohols, lecithin, linoleic acid, meglumine, N- methylpyrrolidone, / V-hydroxyethylpyrrolidone, niacinamide, non-ionic emulsifying wax, oleic acid, oleyl alcohol, phospholipids, polacrilin resin, poloxamer, polymethacrylates, polyethylene glycol 200-600 polyoxyethylene alkyl ethers, polyoxyethylene castor oil derivatives, polyoxyethylene sorbitan fatty acid esters, polyoxyl 15 hydroxystearate, polyoxylglycerides, polyvinyl acetate phthalate, povidone, propylene glycol, propylene glycol dilaurate, propylene glycol monolaurate, pyrrolidone, sodium bicarbonate, sodium lauryl sulfate, sodium polystyrene sulfonate, sorbitan esters, stearic acid, sucrose palmitate, sucrose stearate, transctor, triacetin, triethyl citrate, tricaprylin, trimethyl-p- cyclodextrin, triolein, tocopherol polyethylene glycol succinate or a pharmaceutically or veterinary acceptable salt or combination of any of the foregoing; a soothing agent such as oatmeal, menthol, menthol derivatives (e.g. methone glycerol acetyl and menthyl esters), carboxamides, menthane glycerol ketals, alkyl-substituted ureas, sulfonamides, terpene analogues, furanones, phosphine oxides, aloe vera or a pharmaceutically or veterinary acceptable salt or combination of any of the foregoing; a stabilising agent such as ascorbic acid, ascorbyl palmitate, calcium acetate, calcium stearate, diethanolamine, ethylcellulose, guar gum, hectorite, invert sugar, lauric acid, lecithin, mineral oil, lanolin alcohols, monoethanolamine, phospholipids, poloxamer, potassium chloride, povidone, sodium stearyl fumarate, stearyl alcohol, tagatose, triethanolamine, white wax, xylitol or a pharmaceutically or veterinary acceptable salt or combination of any of the foregoing; a sustained release agent such as acetyltri butyl citrate, hydroxypropyl cellulose,hydroxypropyl methylcellulose phthalate, mannitol, methylcellulose, peanut oil, polyethylene oxide, polyvinyl alcohol, sesame oil, sodium acetate, sodium alginate, stearic acid, sucrose stearate, sugar spheres, tributyl citrate, white wax, yellow wax, zein or a pharmaceutically or veterinary acceptable salt or combination of any of the foregoing; a tonicity agent such as boric acid, sodium acid phosphate buffer, sodium chloride, glucose, potassium chloride, calcium chloride, magnesium chloride, polypropylene glycol, glycerol, a cyclodextrin, corn syrup solids, dextrose, glycerin, magnesium oxide, maltodextrin, mannitol, sorbitol or a pharmaceutically or veterinary acceptable salt or combination of any of the foregoing; a vitamin such as vitamin Bl (thiamin), vitamin c, vitamin c palmitate, vitamin c sodium, tocopherol polyethylene glycol succinate, vitamin F or a pharmaceutically or veterinary acceptable salt or combination of any of the foregoing; a plant extract such as olive oil, garlic bulb extract, mullein flower extract, calendula flower extract or tea tree leaf oil; a wax such as carnauba wax, ceresin wax, cetyl esters wax, non-ionic emulsifying wax, spermaceti, ozokerite wax or a combination thereof; and / or a drying agent such as aluminum acetate solution; an earwax softener such as docusate, olive oil, sodium bicarbonate, urea, hydrogen peroxide; a peroxide; glycolic acid; a bioactive lipid such as a sphingolipid or a phospholipid; an enzyme such as lactoferrin, lactoperoxidase or lysozyme; a growth factor; a probiotic; a biofilm-targeted antibody such as Anti-rsPilA or Anti-tip-chimer antibody; or a combination thereof.

[0126] In some embodiments, the composition comprises, consists or consists essentially of PHMB or a pharmaceutically or veterinary acceptable salt thereof, a chelating agent, a buffering agent, a rheology modifier, a preservative, a surfactant and an aqueous carrier. In particular embodiments, the composition comprises, consists or consists essentially of PHMB or a pharmaceutically or veterinary acceptable salt thereof, a chelating agent, a buffering agent, a rheology modifier, a preservative, a non-ionic surfactant and an aqueous carrier. In some embodiments, the composition comprises, consists or consists essentially of PHMB or a pharmaceutically or veterinary acceptable salt thereof, EDTA or a pharmaceutically or veterinary acceptable salt thereof, Tris or a pharmaceutically or veterinary acceptable salt thereof, propylene glycol, methyl hydroxybenzoate, propyl 4- hydroxybenzoate, cocamidopropyl betaine and water. In specific embodiments, the composition comprises, consists or consists essentially of PHMB, disodium EDTA, Tris, Tris hydrochloride, propylene glycol, methyl hydroxybenzoate, propyl 4-hydroxybenzoate, cocamidopropyl betaine and water.

[0127] In some embodiments, the composition comprises, consists or consists essentially of:PHMB or a pharmaceutically or veterinary acceptable salt thereof in an amount of about 0.05% to about 0.2% w / v; a chelating agent in an amount of about 0.12% w / v;a buffering agent in an amount of about 0.76% w / v; propylene glycol in an amount of about 5% w / v; a surfactant in an amount of about 0.015% to about 2% w / v; a preservative in an amount of about 0.13% w / v; and an aqueous carrier.

[0128] In some embodiments, the composition comprises, consists or consists essentially of:PHMB or a pharmaceutically or veterinary acceptable salt thereof in an amount of about 0.2%, about 0.1% or about 0.05% w / v;EDTA or a pharmaceutically or veterinary acceptable salt thereof in an amount of about 0.12% w / v;Tris and / or a pharmaceutically or veterinary acceptable salt thereof in an amount of about 0.757% w / v; propylene glycol in an amount of about 5% w / v; methyl hydroxybenzoate in an amount of about 0.1% w / v; propyl 4-hydroxybenzoate in an amount of about 0.03% w / v; cocamidopropyl betaine in an amount of about 0.015% w / v; and an aqueous carrier, such as water.

[0129] In some embodiments, the composition comprises, consists or consists essentially of:PHMB or a pharmaceutically or veterinary acceptable salt thereof in an amount of about 0.1% w / v;EDTA or a pharmaceutically or veterinary acceptable salt thereof (e.g. disodium EDTA) in an amount of about 0.12% w / v;Tris and / or a pharmaceutically or veterinary acceptable salt thereof (e.g. Tris and Tris HCI) in an amount of about 0.76% w / v; propylene glycol in an amount of about 5% w / v; methyl hydroxybenzoate in an amount of about 0.1% w / v; propyl 4-hydroxybenzoate in an amount of about 0.03% w / v; cocamidopropyl betaine in an amount of about 0.015% w / v; and an aqueous carrier, such as water.

[0130] In some embodiments, the composition comprises, consists or consists essentially of:PHMB or a pharmaceutically or veterinary acceptable salt thereof in an amount of about 0.1% w / v;EDTA or a pharmaceutically or veterinary acceptable salt thereof (e.g. disodium EDTA) in an amount of about 0.12% w / v;Tris and / or a pharmaceutically or veterinary acceptable salt thereof (e.g. Tris and Tris HCI) in an amount of about 0.76% w / v; propylene glycol in an amount of about 5% w / v; phenoxyethanol in an amount of about 1% w / v; chlorphenesin in an amount of about 0.3% w / v; polyoxylglycerides in an amount of about 0.05% to about 2% w / v; and an aqueous carrier, such as water.

[0131] In some embodiments, the composition comprises, consists or consists essentially of:PHMB or a pharmaceutically or veterinary acceptable salt thereof in an amount of about 0.1% w / v;EDTA or a pharmaceutically or veterinary acceptable salt thereof (e.g. disodium EDTA) in an amount of about 0.12% w / v;Tris and / or a pharmaceutically or veterinary acceptable salt thereof (e.g. Tris and Tris HCI) in an amount of about 0.76% w / v; propylene glycol in an amount of about 5% w / v; phenoxyethanol in an amount of about 1% w / v; chlorphenesin in an amount of about 0.3% w / v; polyoxylglycerides in an amount of about 0.05% to about 2% w / v; cetrimonium salts in an amount of about 0.25% w / v; and an aqueous carrier, such as water.

[0132] While the composition may not comprise further active agents, the administration of other active agents concurrently with the composition or the inclusion of other active agents in the composition is within the scope of the invention. For example, in some embodiments, the composition further comprises or may be administered concurrently with one or more anti-inflammatory agents, anti-allergic agents, antibiotics, anti-fungal agents, antimicrobial agents or local anaesthetics. The composition may be therapeutically used after the other active agent or may be therapeutically used together with the other active agent. The composition may be administered separately, simultaneously or sequentially with the other active agent.

[0133] Accordingly, in some embodiments, the composition further comprises an anti-inflammatory agent, anti-allergic agent, antibiotic, anti-fungal agent or local anaesthetic.

[0134] Exemplary anti-inflammatory agents include NSAIDs (e.g. acetylsalicylic acid (aspirin), diclofenac, diflusinal, etodolac, fenbufen, fenoprofen, flufenisal, flurbiprofen, ibuprofen, indomethacin, ketoprofen, ketorolac, meclofenamic acid, mefenamic acid, meloxicam, nabumetone, naproxen, nimesulide, nitroflurbiprofen, olsalazine, oxaprozin,phenylbutazone, piroxicam, sulfasalazine, sulindac, tolmetin, zomepirac, celecoxib, deracoxib, etoricoxib, mavacoxib, phenazone, suprofen or parecoxib), disease-modifying antirheumatic drugs (DMARDs) (e.g. methotrexate, leflunomide, sulfasalazine, hydroxychloroquinone, penicillamine, anatacept, baricitinib, cetolizumab, sarilumab, tocilizumab or tofacitinib), prednisone, methylprednisolone, dexamethasone, hydrocortisone, budesonide, mometasone, prednisolone, etanercept, golimumab, infliximab, adalimumab, anakinra, rituximab, natalizumab, abatacept, betamethasone, fluocinolone and triamcinolone.

[0135] Suitable anti-allergic drugs include, but are not limited to, cromolyn, emedastine, olopatadine and cyclosporine.

[0136] Exemplary antibiotics include aminoglycosides e.g. kanamycin A, amikacin, tobramycin, dibekacin, gentamicin, sisomicin, netilmicin, neomycins B, C, E and streptomycin; carbacephems e.g. loracarbef; carbapenems e.g. ertapenem, doripenem, imipenem and meropenem; cephalosporins e.g. cefadroxil, cephazolin, cefalotin, cephalexin, cefaclor, cefamandole, cefprozil, cefuroxime, cefixime, cefdinir, cefditoren, cefoperazone, cefotaxime, cefpodoxime, ceftazidime, ceftibuten, ceftizoxime, ceftriaxone, cefepime, ceftaroline fosamil, cefepime, ceftaroline fosamil, cefiderocol and ceftobipriole; cephamycin e.g. cefoxitin, cefotetan and cefmetazole; glycopeptides e.g. teicoplanin, vancomycin, telavancin, dalbavancin and oritavancin; lincosamides e.g. clindamycin and lincomycin; lipopeptides e.g. daptomycin; macrolides e.g. azithromycin, clarithromycin, dirithromycin, erythromycin, roxithromycin, troleandomycin, telithomycin and spiramycin; nitrofurans e.g. furazolidine and nitrofurantoin; oxazolidinones e.g. linezolid, posizolid, radezolid and torezolid; penicillins e.g. amoxicillin, ampicillin, azlocilin, carbenicillin, cioxacillin, dicloxacillin, flucioxacillin, mezlocillin, methicillin, nafcillin, oxacillin, penicillin, penicillin G (benzylpenicillin), penicillin V (phenoxymethylpenicillin), piperacillin, temocillin and ticarcillin; polypeptides e.g. bacitracin; quinolones and fluoroquinolones e.g. ciprofloxacin, enrofloxacin, gatifloxacin, gemifloxacin, levofloxacin, lomefloxacin, moxifloxacin, nalidixic acid, marbofloxacin and norfloxacin; sulfonamides e.g. mafenide, silfacetaminde, sulfadiazine, silver sulfadiazine, sulfadimethoxazine, sulfamethoxazole, sulfamethizole, sulfasalazine and sulfisoxazole; tetracyclines e.g. chlortetracycline, demecolcycline, doxycycline, lymecycline, methacycline, minocycline, oxytetracycline, rolitetracycline, tetracycline, eravacycline, sarecycline, omadacycline and tigecycline; chloramphenicol; fosfomycin; fusidic acid; metronidazole; mupirocin; thiamphenicol; tigecycline; tinidazole; trimethoprim; rifampicin; rifapentine; pyrazinamide; isoniazid; ethionamide; ethambutol; cycloserine; dapsone; clofazimine; or a pharmaceutically or veterinary acceptable salt or combination of any of the foregoing.

[0137] Suitable anti-fungals include, but are not limited to, amphotericin B, amphotericin B cholesteryl sulfate complex, amphotericin B lipid complex, amphotericin Bliposomal, anidulafungin, caspofungin, clotrimazole, fluconazole, flucytosine, griseofulvin, griseofulvin microsize, griseofulvin ultramicrosize, isavuconazonium, itraconazole, ketoconazole, micafungin, miconazole, nystatin, posaconazole, terbinafine, voriconazole, fosfluconazole, isavuconazole, candicidin, hamycin, natamycin, bifonazole, butoconazole, econazole, fenticonazole, isoconazole, luliconazole, omoconazole, oxiconazole, sertaconazole, sulconazole, tioconazole, albaconazole, efinaconazole, terconazole, abafungin, amofolfin, butenafine, naftifine, ciclopirox, tolnafate, orotomide, oteseconazole (VT-1161, (2R)-2-(2,4-difluorophenyl)-l,l-difluoro-3-(tetrazol-l-yl)-l-[5-[4-(2,2,2- trifluoroethoxy)phenyl]pyridin-2-yl]propan-2-ol), ibrexafungerp (SCY-078, 2-(2-amino- 2,3,3-trimethylbutoxy)-l,6a,8,10a-tetramethyl-8-(3-methylbutan-2-yl)-3-(5-(pyridin-4- yl)-lH-l,2,4-triazol-l-yl)-l,3,4,6,6a,7,8,9,10,10a,10b,ll,12,12a-tetradecahydro-2H- l,4a-(methanooxymethano)chrysene-7-carboxylic acid), rezafungin (CD-101, 2-(((2R,9S,llR,12R,14aS,15S,16S,20S,25aS)-23-((lS,2S)-l,2-dihydroxy-2-(4- hydroxyphenyl)ethyl)-2,ll,15-trihydroxy-6,20-bis((R)-l-hydroxyethyl)-16-methyl- 5,8,14,19,22,25-hexaoxo-9-(4"-(pentyloxy)-[l,l':4',l"-terphenyl]-4- carboxamido)tetracosahydro-lH-dipyrrolo[2,l-c:2',l'- l][l,4,7,10,13,16]hexaazacyclohenicosin-12-yl)oxy)-N,N,N-trimethylethan-l-aminium acetate), or a pharmaceutically or veterinary acceptable salt or combination of any of the foregoing.

[0138] Suitable local anaesthetics include, but are not limited to, lidocaine, benzocaine, prilocaine, tetracaine or a pharmaceutically or veterinary acceptable salt or combination of any of the foregoing.

[0139] In the case of compositions containing supplementary active ingredients, the dosages are determined by reference to the usual dose and manner of administration of the said ingredients.

[0140] While non-pharmaceutical and non-veterinary uses are encompassed by the present invention, in particular embodiments, the composition is a pharmaceutical composition or a veterinary composition.

[0141] The compositions of the invention may be administered through a variety of routes including, but not limited to, oral, topical, intranasal, inhalational, otic, transmucosal or intravaginal administration. In particular embodiments, the pharmaceutical composition is administered via inhalational, topical or otic administration. The composition may be administered in the form of a disinfecting solution or irrigant, for example, to disinfect a surface, such as skin, a wound (e.g. a surgical wound), a surgical instrument, a mucous membrane, a body membrane, an internal body surface or an external body surface. In some embodiments, the composition is administered via a route other than otic administration (i.e. administration to an ear or the ear canal).

[0142] The pharmaceutical or veterinary forms suitable for use include sterile solutions or dispersions (e.g. suitable for instillation, disinfection, irrigation, use as a gargle or rinse, intranasal, inhalational or topical administration) and sterile powders (e.g. suitable for the preparation of sterile solutions or dispersions or for administration via intranasal or inhalational administration). The composition of the invention may be formulated, for example, as an emulsion, cream, lotion, gel, hydrogel, jelly, paste, ointment, solution, salve, suspension, dry foam, mousse, suspoemulsion, powder, aerosol, balm, tablet or capsule. In some embodiments, the composition of the invention is a solution. In some embodiments, the composition is in the form of a nasal spray, nasal lavage, ear wash, ear drop, ear lavage, ear spray, throat spray, douche, wound or skin cleansing solution, wound or skin cleansing spray, lung aspirant, aerosol, film, tonic, lavage, flush, stick, seal or strip. In some embodiments, the composition of the invention is administered in the form of a moistened swab, cotton, gauze, bandage, wrap, sponge, cloth, dressing, pad, towel or tampon, or may be in the form of a hydrator for a swab, cotton, gauze, bandage, wrap, sponge, cloth, dressing, pad, towel, foam or tampon. Such preparations may be veterinary or pharmaceutically acceptable.

[0143] The composition of the invention may form part of a personal care formulation, such as a scrub, soak, bath tablet, bath capsule, bath salt, bubble bath solution, makeup remover, tonic, shampoo, conditioner, leave-on treatment, hair grooming aid, hair colouring preparation, bleach, body paint, manicure or pedicure preparation, oral hygiene product (e.g. mouthwash), deodorant, douche, feminine hygiene deodorant, shaving preparation (e.g. shaving cream or aftershave), eye cream, spot treatment, skin freshener, cleanser, serum, moisturiser, masque, body wash, suntan preparation, toner or other toiletry preparations. A person of skill in the art would readily be able to determine suitable additives for such formulations.

[0144] In some embodiments, the composition is other than a contact lens solution or contact lens cleaning solution.

[0145] The compositions may be readily prepared by mixing the components.

[0146] Sterile solutions may be prepared by combining the ingredients in the required amount with other excipients as described above as required, followed by sterilization, such as filtration. Generally, dispersions are prepared by incorporating the various sterilized ingredients into a sterile vehicle which contains the basic dispersion medium and the required excipients as described above. Sterile dry powders may be prepared by vacuum- or freeze-drying a sterile solution comprising the active ingredients and other required excipients as described above.

[0147] Lotion, cream or gel formulations may include, for example, an oil, wax, emollient, rheology modifier and / or ointment base as described herein to impart the desired consistency.

[0148] Preparations for oral use can be obtained by combining the active agents with solid excipients and processing the mixture of granules, after adding suitable auxiliaries, if desired, to obtain tablets or dragee cores. Suitable excipients are, in particular, fillers such as sugars, including lactose, sucrose, mannitol, or sorbitol; cellulose preparations such as, for example, maize starch, wheat starch, rice starch, potato starch, gelatin, gum tragacanth, methyl cellulose, hydroxypropylmethyl-cellulose, sodium carboxymethylcellulose and / or polyvinylpyrrolidone. If desired, disintegrating agents may be added, such as the cross-linked polyvinyl pyrrolidone, agar or alginic acid or a salt thereof, such as sodium alginate. Such compositions may be prepared by any of the methods of pharmacy but all methods include the step of bringing into association one or more active agents as described above with the carrier which constitutes one or more necessary ingredients. In general, the compositions of the invention may be manufactured in a manner that is itself known, e.g. by means of conventional mixing, dissolving, granulating, dragee-making, levigating, emulsifying, encapsulating, entrapping or lyophilising processes.

[0149] Dragee cores are provided with suitable coatings. For this purpose, concentrated sugar solutions may be used, which may optionally contain gum arabic, talc, polyvinyl pyrrolidone, carbopol gel, polyethylene glycol, and / or titanium dioxide, lacquer solutions and suitable organic solvents or solvent mixtures. Dyestuffs or pigments may be added to the tablets or dragee coatings for identification or to characterise different combinations of particle doses.

[0150] Oral formulations which can be used orally include push-fit capsules made of gelatin, as well as soft, sealed capsules made of gelatin and a plasticiser, such as glycerol or sorbitol. The push-fit capsules can contain the active ingredients in admixture with filler such as lactose, binders such as starches, and / or lubricants such as talc or magnesium stearate and, optionally, stabilisers. In soft capsules, the active agents may be dissolved or suspended in suitable liquids, such as fatty oils, liquid paraffin, or liquid polyethylene glycols. In addition, stabilisers may be added as discussed herein.

[0151] In some embodiments, the compositions are suitable for inhalation or intranasal delivery and are in the form of, for example, solutions, aerosols, dry powders, suspensions or emulsions. For example, the composition may be administered to the respiratory tract as a nasal or pulmonary inhalation aerosol or solution for a nebuliser, or as a powder for insufflation, alone or in combination with an inert carrier, such as lactose, glucose or mannitol, or with other pharmaceutically or veterinary acceptable excipients,such as beta-cyclodextrin, starch, sodium carboxymethylcellulose and the like as discussed above. The composition may be administered by, for example, a dry powder inhaler, a soft mist inhaler, a nebuliser or a metered dose inhaler.

[0152] Aerosol formulations include those in which the composition is provided in a pressurised pack with a suitable propellant such as a metered dose inhaler. Whilst the propellant may be a chlorofluorocarbon (CFC) (such as dichlorodifluoromethane, trichlorofluoromethane or 1,2-dichlorotetrafluoroethane), the propellant is more preferably a non-chlorofluorocarbon propellant such as carbon dioxide, a hydrofluoroalkane [such as 1,1,1,2-tetrafluoroethane (HFA-134a), 1,1,1,2,3,3,3-heptafluoropropane (HFA-227) or 1,1,1,2,3,3,3-heptafluoroethane (HFA-227ea)] or another suitable gas.

[0153] The dose of the composition may be controlled by provision of a metered valve. The specific particle size used will depend on the target site and a skilled person will readily be able to determine suitable particle sizes. For example, a particle size of approximately 1 to 5 pm is useful for delivery to the lung, as particles smaller than 1 pm are generally exhaled without delivery to the lung, and particles larger than 10 pm are mostly trapped by oropharyngeal deposition and do not reach the lung. Devices propelled by HFA-134a deliver smaller droplets which penetrate more readily into the bronchial airways. For drug delivery via the nasal passage, a suitable particle size is, for example, 20-80 pm, as smaller particles (less than 10 pm) get carried into the tracheobrachial region, whilst bigger particles (greater than 100 pm) get rapidly cleared from the nasal passageway.

[0154] The compositions of the invention are useful for disrupting and eradicating biofilms, treating or inhibiting the development of an infection, and / or increasing the susceptibility of bacteria to antibiotics. Accordingly, in one aspect, there is provided a method of disrupting or eradicating a biofilm, comprising, consisting or consisting essentially of contacting the biofilm with a composition comprising PHMB or a pharmaceutically or veterinary acceptable salt thereof, a chelating agent and a buffering agent. Also provided is a composition comprising PHMB or a pharmaceutically or veterinary acceptable salt thereof, a chelating agent and a buffering agent for use in disrupting or eradicating a biofilm; a use of a composition comprising PHMB or a pharmaceutically or veterinary acceptable salt thereof, a chelating agent and a buffering agent for disrupting or eradicating a biofilm; and a use of PHMB or a pharmaceutically or veterinary acceptable salt thereof, a chelating agent and a buffering agent in the manufacture of a medicament for disrupting or eradicating a biofilm.

[0155] Suitable embodiments of the composition are as described supra.

[0156] The biofilm may comprise bacteria and / or fungi. For example, suitable bacteria include, but are not limited to, Staphylococcus spp. (e.g. Staphylococcuspseudintermedius, Staphylococcus aureus, Staphylococcus epidermidis, Staphylococcus capitis, Staphylococcus hominis, Staphylococcus haemolyticus, Staphylococcus saccharolyticus, Staphylococcus warneri, Staphylococcus lugdunensis, Staphylococcus saprophyticus, Staphylococcus schleiferi or Staphylococcus cohnii), Pseudomonas spp. (e.g. Pseudomonas aeruginosa or Pseudomonas pseudomallei'), Escherichia spp. (e.g. Escherichia coli), Proteus spp. (e.g. Proteus mirabilis or Proteus vulgaris), Streptococcus spp. (e.g. Streptococcus canis, Streptococcus mutans, Streptococcus pneumoniae, Streptococcus pyogenes, Streptococcus agalactiae, Streptococcus oralis, Streptococcus gordonii, Streptococcus sanguinis, Streptococcus anginosus, Streptococcus constellatus, Streptococcus viridans or Streptococcus intermedius), Burkholderia spp. (e.g. Burkholderia cepacia, Burkholderia cenocepacia, Burkholderia multivorans, Burkholderia pseudomallei or Burkholderia dolosa), Klebsiella spp. (e.g. Klebsiella oxytoca, Klebsiella pneumoniae or Klebsiella aerogenes), Enterococcus spp. (e.g. Enterococcus faecalis, Enterococcus canintestini, Enterococcus faecium, Enterococcus casseliflavus or Enterococcus gallinarum), Corynebacterium spp. (e.g. Corynebacterium auriscanis, Corynebacterium amycolatum, Corynebacterium striatum, Corynebacterium pseudotuberculosis, Corynebacterium urealyticum or Corynebacterium diphtheriae), Serratia spp. (e.g. Serratia marcescens) or Haemophilus spp. (e.g. Haemophilus influenzae). In particular embodiments, the bacteria is a Staphylococcus spp., Pseudomonas spp., Escherichia spp., Proteus spp., Streptococcus spp., Burkholderia spp., Klebsiella spp., Enterococcus spp., Corynebacterium spp. and Serratia spp.. In some embodiments, the bacteria is Staphylococcus pseudintermedius, Pseudomonas aeruginosa, Escherichia coli, Proteus mirabilis, Streptococcus canis, Burkholderia cepacia, Burkholderia cenocepacia, Burkholderia multivorans, Staphylococcus aureus, Klebsiella oxytoca, Klebsiella pneumoniae, Klebsiella aerogenes, Enterococcus faecalis, Enterococcus canintestini, Corynebacterium auriscanis, Corynebacterium amycolatum and / or Serratia marcescens.

[0157] In particular embodiments, the bacterium is resistant to at least one antibiotic. Representative classes and examples of antibiotics include aminoglycosides e.g. kanamycin A, amikacin, tobramycin, dibekacin, gentamicin, sisomicin, netilmicin, neomycins B, C, E and streptomycin; carbacephems e.g. loracarbef; carbapenems e.g. ertapenem, doripenem, imipenem and meropenem; cephalosporins e.g. cefadroxil, cephazolin, cefalotin, cephalexin, cefaclor, cefamandole, cefprozil, cefuroxime, cefixime, cefdinir, cefditoren, cefoperazone, cefotaxime, cefpodoxime, ceftazidime, ceftibuten, ceftizoxime, ceftriaxone, cefepime, ceftaroline fosamil, cefepime, ceftaroline fosamil, cefiderocol and ceftobipriole; cephamycin e.g. cefoxitin, cefotetan and cefmetazole; glycopeptides e.g. teicoplanin, vancomycin, telavancin, dalbavancin and oritavancin; lincosamides e.g. clindamycin and lincomycin; lipopeptides e.g. daptomycin; macrolides e.g. azithromycin, clarithromycin, dirithromycin, erythromycin, roxithromycin,troleandomycin, telithomycin and spiramycin; nitrofurans e.g. furazolidine and nitrofurantoin; oxazolidinones e.g. linezolid, posizolid, radezolid and torezolid; penicillins e.g. amoxicillin, ampicillin, azlocilin, carbenicillin, cioxacillin, dicloxacillin, flucioxacillin, mezlocillin, methicillin, nafcillin, oxacillin, penicillin, penicillin G (benzylpenicillin), penicillin V (phenoxymethylpenicillin), piperacillin, temocillin and ticarcillin; polypeptides e.g. bacitracin; quinolones and fluoroquinolones e.g. ciprofloxacin, enrofloxacin, gatifloxacin, gemifloxacin, levofloxacin, lomefloxacin, moxifloxacin, nalidixic acid, marbofloxacin and norfloxacin; sulfonamides e.g. mafenide, silfacetaminde, sulfadiazine, silver sulfadiazine, sulfadimethoxazine, sulfamethoxazole, sulfamethizole, sulfasalazine and sulfisoxazole; tetracyclines e.g. chlortetracycline, demecolcycline, doxycycline, lymecycline, methacycline, minocycline, oxytetracycline, rolitetracycline, tetracycline, eravacycline, sarecycline, omadacycline and tigecycline; chloramphenicol; fosfomycin; fusidic acid; metronidazole; mupirocin; thiamphenicol; tigecycline; tinidazole; trimethoprim; rifampicin; rifapentine; pyrazinamide; isoniazid; ethionamide; ethambutol; cycloserine; dapsone and clofazimine. In some embodiments, the bacterium is resistant to a fluoroquinolone or an aminoglycoside, such as enrofloxacin, gentamicin or marbofloxacin.

[0158] The biofilm may, alternatively or in addition, comprise a fungi, such as a Candida spp. (e.g. Candida albicans, Candida glabrata, Candida tropicalis or Candida parapsilosis), Malassezia spp. (e.g. Malassezia pachydermatis or Malassezia furfur), ringworm such as Microsporum spp. or Trichophyton spp., Aspergillus spp. or Cryptococcus spp.. In some embodiments, the biofilm comprises a Malassezia spp., particularly M. pachydermatis.

[0159] Candida spp. are able to form biofilms on living and non-living surfaces, and can form multi-species biofilms with bacteria, which could escalate the virulence. C. albicans forms polymicrobial biofilms with S. aureus, which can lead to synergism and has been shown to result in increased mortality in mice. The treatment and eradication of such biofilms could require a higher concentration of antibiotics.

[0160] The biofilm may be present on any surface, such as a mucous membrane, skin, a wound (e.g. a wound caused by mechanical trauma, such as physical trauma caused by an accident or a burn or a surgical wound), a body membrane, an internal body surface or an external body surface of a subject such as a human or a non-human animal. In some embodiments, the surface is skin or a mucous membrane, such as a mucous membrane lining the respiratory tract, urinary tract, reproductive organ or ear including the ear canal. In some embodiments, the surface is the surface lining the ear or ear canal, for example, the external ear or middle ear. In particular embodiments, the surface is exposed to the external environment (e.g. air outside of the subject). In alternative embodiments, the surface is other than a surface in or of the ear, such as a canine ear canal.

[0161] Alternatively, the biofilm may be present on a surgical instrument, medical device (e.g. the surface of an endotracheal tube, catheter or an implanted device such as an orthopaedic implant, cochlear implant, dental implant or catheter including a vascular catheter) or any other surface needing to be sterilised or disinfected, such as a surface in a clinical setting (e.g. table, bed, floor and the like).

[0162] In some embodiments, the biofilm is other than a biofilm on a contact lens (i.e. the surface is other than a contact lens). In some embodiments, the biofilm is other than a biofilm on a catheter (i.e. the surface is other than a catheter).

[0163] The biofilm may be contacted with the composition for a suitable time to disrupt or eradicate the biofilm. For example, in some embodiments, the biofilm is contacted with the composition for a period of between about 10 seconds and about 24 hours (and all integer seconds in between), about 30 seconds and about 24 hours, about 1 minute and about 24 hours, about 30 minutes and about 24 hours, about 1.5 and about 24 hours, about 3 and about 24 hours, about 30 minutes and about 3 hours, about 30 minutes and about 1.5 hours or about 1.5 and about 3 hours. In some embodiments, the biofilm is contacted with the composition for at least about 10, 15, 20, 25, 30, 35, 40, 45, 50, 55 or 60 seconds; or about 10, 15, 20, 25, 30, 35, 40, 45, 50, 55 or 60 seconds. In some embodiments, the biofilm is contacted with the composition for at least about 30 or 45 minutes or about 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10,11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23 or 24 hours; or about 30 or 45 minutes or about 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10, 11, 12, 13,14, 15, 16, 17, 18, 19, 20, 21, 22, 23 or 24 hours.

[0164] The methods or uses may further comprise contacting the biofilm with an antibiotic. In some embodiments, the biofilm comprises a bacterium that is resistant to the antibiotic. The antibiotic may be applied in an amount which is known to be active against a non-resistant bacterium. The antibiotic and composition of the invention may be applied concurrently, such as simultaneously. In such embodiments, the composition may further comprise an antibiotic. In particular embodiments, the antibiotic is one to which the bacterium is known to develop resistance.

[0165] The invention also provides a method of treating or inhibiting the development of an infection caused by a bacterium selected from the group consisting of Burkholderia spp., Serratia spp., Enterococcus spp. and Corynebacterium spp. in a subject, comprising, consisting or consisting essentially of administering a composition comprising PHMB or a pharmaceutically or veterinary acceptable salt thereof, a chelating agent and a buffering agent to the subject. Further provided is a composition comprising PHMB or a pharmaceutically or veterinary acceptable salt thereof, a chelating agent and a buffering agent for use in treating or inhibiting the development of an infection caused by abacterium selected from the group consisting of Burkholderia spp., Serratia spp., Enterococcus spp. and Corynebacterium spp. in a subject; a use of a composition comprising PHMB or a pharmaceutically or veterinary acceptable salt thereof, a chelating agent and a buffering agent for treating or inhibiting the development of an infection caused by a bacterium selected from the group consisting of Burkholderia spp., Serratia spp., Enterococcus spp. and Corynebacterium spp. in a subject; and a use of PHMB or a pharmaceutically or veterinary acceptable salt thereof, a chelating agent and a buffering agent in the manufacture of a medicament for treating or inhibiting the development of an infection caused by a bacterium selected from the group consisting of Burkholderia spp., Serratia spp., Enterococcus spp. and Corynebacterium spp. in a subject.

[0166] Suitable embodiments of the composition are as described supra.

[0167] In some embodiments, the bacterium is selected from the group consisting of Burkholderia spp., Serratia spp. and Corynebacterium spp.. In some embodiments, the bacterium is selected from the group consisting of Burkholderia spp. and Serratia spp.

[0168] Suitable Burkholderia spp., Serratia spp., Enterococcus spp. and Corynebacterium spp. are discussed above.

[0169] In some embodiments, the bacteria is B. cepacia, B. cenocepacia, B. multivorans, E. faecalis, E. canintestini, C. auriscanis, C. amycolatum, C. urealyticum or S. marcescens. In some embodiments, the bacteria is B. cepacia, B. cenocepacia, B. multivorans, C. auriscanis, C. amycolatum, C. urealyticum or S. marcescens. In some embodiments, the bacteria is B. cepacia, B. cenocepacia, B. multivorans or S. marcescens.

[0170] In some embodiments, the infection is an infection of the ear, skin, respiratory tract (e.g. lower respiratory tract such as the lungs), blood, urinary tract, nose or nasopharynx. In particular embodiments, the infection is an infection of the ear, skin or lower respiratory tract (e.g. lung); especially ear or skin. In some embodiments, the infection is an external ear infection.

[0171] In alternative embodiments, the infection is other than an ear infection. In such embodiments, the infection may be, for example, an infection of the skin, respiratory tract, blood, urinary tract, nose or nasopharynx.

[0172] In particular embodiments, the bacterium is in the form of a biofilm.

[0173] In some embodiments, the subject is suffering from a condition which increases their susceptibility to an infection compared to a subject not having the condition, such as cystic fibrosis, allergies (e.g. food allergy or atopic dermatitis), parasite infection (e.g. a mite such as Otodectes cynotis), neoplasma or an endocrine disorder (e.g. hypothyroidism or hyperadrenocorticism). In some embodiments, the subject is sufferingfrom a condition associated with a bacterial or fungal infection, such as sepsis, superficial pyoderma, deep pyoderma, furunculosis or cellulitis.

[0174] The infection may be caused by a bacterium that is resistant to one or more antibiotics or is known to develop antibiotic resistance. In preferred embodiments, the bacterium is one which is substantially resistant to an antibiotic. In some embodiments, the bacterium is one which is known to develop resistance to an antibiotic. Representative examples of such antibiotics are discussed supra. In some embodiments, the bacterium is resistant to one or more antibiotics selected from the group consisting of fluoroquinolones (e.g. enrofloxacin or marbofloxacin), aminoglycosides (e.g. gentamicin), penicillins (e.g. piperacillin) and cephalosporins. In specific embodiments, the bacterium is resistant to one or more antibiotics selected from the group consisting of fluoroquinolones and aminoglycosides, such as enrofloxacin, gentamicin or marbofloxacin.

[0175] The methods or uses may further comprise administering an antibiotic. In some embodiments, the infection is caused by a bacterium that is resistant to the antibiotic. The antibiotic may be administered in an amount which is known to be active against a non-resistant bacterium. The antibiotic and composition of the invention may be administered concurrently to the subject, such as simultaneously. In such embodiments, the composition may further comprise an antibiotic. In particular embodiments, the antibiotic is one to which the bacterium is known to develop resistance.

[0176] In a further aspect, there is provided a method of conferring antibiotic susceptibility to a resistant bacterium, comprising, consisting or consisting essentially of contacting the bacterium with a composition comprising PHMB or a pharmaceutically or veterinary acceptable salt thereof, a chelating agent and a buffering agent, wherein the bacterium is selected from the group consisting of Burkholderia spp., Serratia spp., Enterococcus spp. and Corynebacterium spp.. Also provided is a composition comprising PHMB or a pharmaceutically or veterinary acceptable salt thereof, a chelating agent and a buffering agent for use in conferring antibiotic susceptibility to a resistant bacterium, wherein the bacterium is selected from the group consisting of Burkholderia spp., Serratia spp., Enterococcus spp. and Corynebacterium spp.; a use of a composition comprising PHMB or a pharmaceutically or veterinary acceptable salt thereof, a chelating agent and a buffering agent for conferring antibiotic susceptibility to a resistant bacterium, wherein the bacterium is selected from the group consisting of Burkholderia spp., Serratia spp., Enterococcus spp. and Corynebacterium spp.; and a use of PHMB or a pharmaceutically or veterinary acceptable salt thereof, a chelating agent and a buffering agent in the manufacture of a medicament for conferring antibiotic susceptibility to a resistant bacterium, wherein the bacterium is selected from the group consisting of Burkholderia spp., Serratia spp., Enterococcus spp. and Corynebacterium spp..

[0177] Suitable embodiments of the composition are as described supra.

[0178] In some embodiments, the bacterium is selected from the group consisting of Burkholderia spp., Serratia spp. and Corynebacterium spp.. In some embodiments, the bacterium is selected from the group consisting of Burkholderia spp. and Serratia spp.

[0179] Suitable Burkholderia spp., Serratia spp., Enterococcus spp. and Corynebacterium spp. are discussed above.

[0180] In some embodiments, the bacteria is B. cepacia, B. cenocepacia, B. multivorans, E. faecalis, E. canintestini, C. auriscanis, C. amycolatum, C. urealyticum or S. marcescens. In some embodiments, the bacteria is B. cepacia, B. cenocepacia, B. multivorans, C. auriscanis, C. amycolatum, C. urealyticum or S. marcescens. In some embodiments, the bacteria is B. cepacia, B. cenocepacia, B. multivorans or S. marcescens.

[0181] Representative examples of suitable antibiotics are discussed supra. In some embodiments, the antibiotic is selected from the group consisting of fluoroquinolones and aminoglycosides, such as enrofloxacin, gentamicin or marbofloxacin.

[0182] The bacterium may be contacted with the composition for a suitable time to confer antibiotic susceptibility. For example, in some embodiments, the bacterium is contacted with the composition for a period of between about 10 seconds and about 24 hours (and all integer seconds in between), about 30 seconds and about 24 hours, about 1 minute and about 24 hours, about 30 minutes and about 24 hours, about 1.5 and about 24 hours, about 3 and about 24 hours, about 30 minutes and about 3 hours, about 30 minutes and about 1.5 hours or about 1.5 and about 3 hours. In some embodiments, the bacterium is contacted with the composition for at least about 10, 15, 20, 25, 30, 35, 40, 45, 50, 55 or 60 seconds; or about 10, 15, 20, 25, 30, 35, 40, 45, 50, 55 or 60 seconds. In some embodiments, the bacterium is contacted with the composition for at least about 30 or 45 minutes or about 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23 or 24 hours; or about 30 or 45 minutes or about 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23 or 24 hours.

[0183] The methods or uses may further comprise administering an antibiotic, especially an antibiotic to which susceptibility has been conferred or one to which the bacterium is known to develop or possess resistance. The antibiotic may be administered in an amount which is known to be active against a non-resistant bacterium. The antibiotic and composition of the invention may be administered concurrently to the subject, such as simultaneously.

[0184] The composition is also useful for increasing the antibiotic susceptibility of bacteria. Accordingly, in a further aspect, there is provided a method of increasing the susceptibility of a bacterium to an antibiotic, comprising, consisting or consisting essentially of contacting the bacterium with a composition comprising PHMB or a pharmaceutically or veterinary acceptable salt thereof, a chelating agent and a buffering agent, wherein the bacterium is selected from the group consisting of Burkholderia spp., Serratia spp., Enterococcus spp. and Corynebacterium spp.. Also provided, in other aspects, is a composition comprising PHMB or a pharmaceutically or veterinary acceptable salt thereof, a chelating agent and a buffering agent for use in increasing the susceptibility of a bacterium to an antibiotic, wherein the bacterium is selected from the group consisting of Burkholderia spp., Serratia spp., Enterococcus spp. and Corynebacterium spp.; a use of a composition comprising PHMB or a pharmaceutically or veterinary acceptable salt thereof, a chelating agent and a buffering agent for increasing the susceptibility of a bacterium to an antibiotic, wherein the bacterium is selected from the group consisting of Burkholderia spp., Serratia spp., Enterococcus spp. and Corynebacterium spp.; and a use of PHMB or a pharmaceutically or veterinary acceptable salt thereof, a chelating agent and a buffering agent in the manufacture of a medicament for increasing the susceptibility of a bacterium to an antibiotic, wherein the bacterium is selected from the group consisting of Burkholderia spp., Serratia spp., Enterococcus spp. and Corynebacterium spp..

[0185] Suitable embodiments of the composition and antibiotics are described supra. In some embodiments, the antibiotic is selected from the group consisting of fluoroquinolones and aminoglycosides, such as enrofloxacin, gentamicin or marbofloxacin.

[0186] In some embodiments, the bacterium is selected from the group consisting of Burkholderia spp., Serratia spp. and Corynebacterium spp.. In some embodiments, the bacterium is selected from the group consisting of Burkholderia spp. and Serratia spp.

[0187] Suitable Burkholderia spp., Serratia spp., Enterococcus spp. and Corynebacterium spp. are discussed above.

[0188] In some embodiments, the bacteria is B. cepacia, B. cenocepacia, B. multivorans, E. faecalis, E. canintestini, C. auriscanis, C. amycolatum, C. urealyticum or S. marcescens. In some embodiments, the bacteria is B. cepacia, B. cenocepacia, B. multivorans, C. auriscanis, C. amycolatum, C. urealyticum or S. marcescens. In some embodiments, the bacteria is B. cepacia, B. cenocepacia, B. multivorans or S. marcescens.

[0189] In some embodiments, the bacterium is present in or on the ear, skin, respiratory tract (e.g. lower respiratory tract such as the lungs), blood, urinary tract, nose or nasopharynx of a subject. In particular embodiments, the bacterium is present in or onthe ear, skin or lower respiratory tract (e.g. lung) of a subject; especially ear or skin. In some embodiments, the bacterium is present in the external ear or middle ear of a subject.

[0190] In alternative embodiments, the bacterium is present in or on the skin, respiratory tract, blood, urinary tract, nose or nasopharynx of a subject. In some embodiments, the bacterium is not contacted with the composition in an ear of a subject.

[0191] In particular embodiments, the bacterium is in the form of a biofilm.

[0192] In some embodiments, the bacterium is resistant to the antibiotic. In particular embodiments, the bacterium is substantially resistant to the antibiotic or is developing resistance to the antibiotic.

[0193] The methods and uses may further comprise contacting the bacterium with the antibiotic. The bacterium may be contacted concurrently (e.g. simultaneously, separately or sequentially) with the composition and antibiotic.

[0194] The bacterium may be contacted with the composition for a suitable time to increase the susceptibility of the bacterium to the antibiotic. For example, in some embodiments, the bacterium is contacted with the composition for a period of between about 10 seconds and about 24 hours (and all integer seconds in between), about 30 seconds and about 24 hours, about 1 minute and about 24 hours, about 30 minutes and about 24 hours, about 1.5 and about 24 hours, about 3 and about 24 hours, about 30 minutes and about 3 hours, about 30 minutes and about 1.5 hours or about 1.5 and about 3 hours. In some embodiments, the bacterium is contacted with the composition for at least about 10, 15, 20, 25, 30, 35, 40, 45, 50, 55 or 60 seconds; or about 10, 15, 20, 25, 30, 35, 40, 45, 50, 55 or 60 seconds. In some embodiments, the bacterium is contacted with the composition for at least about 30 or 45 minutes or about 1, 1.5, 2, 2.5, 3, 3.5, 4,4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23 or 24 hours; or about 30 or 45 minutes or about 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5,5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23 or 24 hours.

[0195] Also contemplated, is the use of a composition comprising PHMB or a pharmaceutically or veterinary acceptable salt thereof, a chelating agent and a buffering agent, for increasing an activity of an antibiotic against a bacterium, wherein the bacterium is in the form of a biofilm or is selected from the group consisting of Burkholderia spp., Serratia spp., Enterococcus spp. and Corynebacterium spp. The bacterium may be contacted with the composition. In particular embodiments, the bacterium is contacted with the composition and the antibiotic concurrently (e.g. simultaneously), for example, when the composition comprises the antibiotic. In some embodiments, the bacterium is not contacted with the composition in an ear of a subject.

[0196] Suitable bacterium, antibiotics and embodiments of the composition are described supra.

[0197] In some embodiments, the activity of an antibiotic is antibacterial activity. In particular embodiments, the activity of the antibiotic is increased compared to the activity of the antibiotic in the absence of the composition of the invention, such as by at least about 2-fold to 100-fold (and all integers in between). In some embodiments, the activity is increased by at least about 2-fold, 3-fold, 4-fold, 5-fold, 10-fold, 15-fold, 20- fold, 30-fold, 40-fold, 50-fold or 100-fold.

[0198] The composition of the invention may also be useful for disinfecting or cleaning a surface, wherein the surface comprises, is suspected of comprising or is at risk of comprising a biofilm and / or a bacterium selected from the group consisting of Burkholderia spp., Serratia spp., Enterococcus spp. and Corynebacterium spp.. Such uses involve contacting the surface with a composition of the invention.

[0199] Suitable bacterium, antibiotics, surfaces and embodiments of the composition are described supra.

[0200] In some embodiments, the surface is skin, a wound (e.g. a wound caused by mechanical trauma, such as physical trauma caused by an accident or a burn or a surgical wound), a body membrane, an internal body surface or an external body surface of a subject such as a human or a non-human animal. In some embodiments, the surface is a mucous membrane, such as a mucous membrane lining the respiratory tract, urinary tract or ear. In some embodiments, the surface is the surface lining the ear, including the ear canal. In some embodiments, the surface is an external ear surface. In alternative embodiments, the surface is other than a surface in or of the ear, such as a canine ear. In some embodiments, the surface is an inanimate surface, such as a surgical instrument or any other surface needing to be sterilised or disinfected, such as a surface in a clinical setting (e.g. table, bed, floor and the like).

[0201] In some embodiments, the surface is other than a contact lens or a catheter.

[0202] The surface may be contacted with the composition for a suitable time to eradicate or kill any biofilm or bacterium on the surface. For example, in some embodiments, the surface is contacted with the composition for a period of between about 10 seconds and about 24 hours (and all integer seconds in between), about 30 seconds and about 24 hours, about 1 minute and about 24 hours, about 30 minutes and about 24 hours, about 1.5 and about 24 hours, about 3 and about 24 hours, about 30 minutes and about 3 hours, about 30 minutes and about 1.5 hours or about 1.5 and about 3 hours. In some embodiments, the surface is contacted with the composition for at least about 10, 15, 20, 25, 30, 35, 40, 45, 50, 55 or 60 seconds; or about 10, 15, 20, 25, 30, 35, 40, 45,50, 55 or 60 seconds. In some embodiments, the surface is contacted with the composition for at least about 30 or 45 minutes or about 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23 or 24 hours; or about 30 or 45 minutes or about 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23 or 24 hours.

[0203] Also contemplated is the use of a composition of the invention as a coating on surgical instruments and medical devices, such as needles, cannulae, sutures, staples, catheters (e.g. a vascular catheter), stents, endotracheal tubes, orthopaedic implants, cochlear implants and dental implants as a prophylactic to mitigate against contracting a bacterial or fungal infection during surgical procedures, intravenous injections, catheterisation and the like. The composition will be particularly useful for mitigating against biofilm formation on such surgical instruments and medical devices.

[0204] In particular embodiments of any one or more of the aspects described herein, the subject is a human, canine or feline subject, such as a human or canine subject. In some embodiments, the subject is a canine subject. In alternative embodiments, the subject is other than a canine subject.

[0205] Any one of the methods and uses described herein may involve administration or use of an effective amount of the composition of the invention. The compound or complex of the invention may be administered to the subject or delivered by any route suitable to effect treatment or inhibition of the development of the disease, disorder or condition, susceptibility of the bacterium or cleaning or disinfecting of the surface. A skilled person will be well aware of suitable routes of administration, such as one or more of the routes of administration discussed supra. For example, in some embodiments, the compound or complex is administered by inhalational, topical or otic administration.

[0206] The dosage and frequency of administration will depend on the subject, the disease, disorder or condition to be treated, the intended use of the composition and / or the route of administration. A skilled person will readily be able to determine suitable dosages and frequency of such dosages. The composition of the invention may be administered at a frequency of, for example, once weekly, twice weekly, once daily, or twice or three times daily. The treatment may be continued for multiple days, weeks, months or years. In embodiments where the pharmaceutical composition comprises one or more additional active agents, the dosages and frequency of administration are determined by reference to the usual dose and manner of administration of the said agents. For example, when in liquid form, the composition of the invention may be administered in an amount of about 0.25 mL to about 5 mL; or when in solid form, PHMB or a pharmaceutically or veterinary acceptable salt thereof may be administered in an amountof about 0.5 mg to about 10 mg (and all one tenth integer mg in between), about 0.25 mg to about 5 mg or about 0.125 mg to about 2.5 mg, the chelating agent may be administered in an amount of about 0.3 mg to about 6 mg (and all one tenth integer mg in between) and the buffering agent may be administered in an amount of about 1.9 mg to about 38 mg (and all one tenth integer mg in between).

[0207] Any one of the methods and uses described above may also involve the administration of one or more further active agents as described supra, such as one or more anti-inflammatory agents, anti-allergic agents, antibiotics, anti-fungal agents or local anaesthetics.

[0208] In order that the invention may be readily understood and put into practical effect, particular preferred embodiments will now be described by way of the following non-limiting examples.EXAMPLES

[0209] Chemicals, reagents and equipment used are commercially available (e.g. from Sigma-Aldrich, Burlington, Massachusetts, USA and the like) and were obtained from commercial sources unless otherwise indicated.EXAMPLE 1 - PREPARATION OF COMPOSITIONS

[0210] A composition comprising 0.2% w / v PHMB was prepared (Composition A). The components of the composition are provided in Table 1.TABLE 1COMPOSITION A

[0211] Buffering agents (Trizma base and Trizma HCI) and disodium ethylenediamine tetraacetic acid were dissolved in purified water. The pH was then adjusted to around neutral with hydrochloric acid. Methyl hydroxybenzoate and propyl 4- hydroxybenzoate were dissolved in propylene glycol and added to the bulk. Gardiquat BSAU was added, followed by Cosmocil CQ. Purified water was added to 1 L and the pH was checked and adjusted if necessary.

[0212] A composition comprising 0.1% w / v PHMB was prepared (Composition B). The components of the composition are provided in Table 2. TABLE 2COMPOSITION B

[0213] Composition B was prepared as per Composition A.

[0214] A composition comprising 0.05% w / v PHMB was prepared (CompositionC). The components of the composition are provided in Table 3.TABLE 3COMPOSITION C

[0215] Composition C was prepared as per Composition A.EXAMPLE 2 - EFFICACY OF COMPOSITIONS AGAINST BIOFILMS

[0216] Recently collected canine otitis externa isolates were obtained and cultured on Sheep Blood Agar. Approximately thirty isolates per species (S. pseudintermedius, P. aeruginosa, E. coli, P. mirabilis, S. canis and M. pachydermatis) were tested for biofilm formation and ten of the strongest biofilm forming isolates were selected per species (refer to Table 4 and Table 5). Most strains of S. pseudintermedius and P. aeruginosa were strong to moderate biofilm producers, while E. coli only consisted of two strong biofilm producers (refer to Table 5). The biofilm formation of different microbes was performed using the Congo red agar method and microtitre plate assay (refer to Table 4). Furthermore, two Enterococcus spp., three Corynebacterium spp., four Klebsiella spp. and one S. marcescens were tested for antibiofilm activity. MBEC / MIC and MBEC / MBC are presented in Table 5. The MBEC / MIC value refers to the ratio of the minimal biofilm eradication concentration (MBEC) over the planktonic minimal inhibitory concentration (MIC) value while MBEC / MBC value refers to the ratio of the MBEC over planktonic minimal bactericidal concentration (MBC). The biofilm production was graded as strong, moderate or weak according to the criteria in Table 6.TABLE 4COMPARISON OF BIOFILM FORMATION BY CONGO RED AGAR METHOD AND MICROTITER PLATEASSAYTABLE 5SELECTED ISOLATES AND THEIR BIOFILM PRODUCTIONTABLE 6INTERPRETATION OF BIOFILM PRODUCTIONwherein: ODc= Average OD of negative control wells

[0217] Microbial biofilms were challenged with Composition A (prepared in accordance with Example 1) in comparison to compositions comprising the adjuvants N- acetyl cysteine (NAC) and Tris-EDTA in the absence of PHMB at a total of 10 dilutions (refer to Figures 1-3 and Tables 7-9). Antibiofilm activity testing was performed using MBEC™ assay biofilm inoculator as per Ceri et al. (1999) Journal of Clinical Microbiology, 37(6): 1771-1776; and Harrison et al. (2010) Nature Protocols, 5(7): 1236-1254. The MBEC is defined as the lowest concentration of the adjuvant that prevents visible growth from occurring in the recovery medium when incubated overnight. This study established that Composition A had an MBEC for ten moderate to high biofilm producing strains of S. pseudintermedius (including four methicillin-resistant (MRSP) isolates) ranging from 1 :8 to 1:32 dilutions of the neat product. By comparison, the highest concentration of the commercial NAC and Tris-EDTA products tested did not eradicate the biofilms. The MBEC of Composition A for one moderate and nine high biofilm producing strains of P. aeruginosa was 1:4 to 1:8 dilutions of the neat product. NAC was found to eradicate some strains of P. aeruginosa at 1 :2 dilution, but was unable to eradicate biofilm production at the highest concentration for the remainder of the isolates. Similar results were found for Tris-EDTA for all isolates. It was also found that Composition A has antibiofilm effects against low to moderate biofilm producing strains of E. coll in dilutions of 1:8-1 :256. In contrast, NAC and Tris-EDTA were not able to eradicate E. coll biofilms at the highest concentration tested .TABLE 7MBEC, MIC AND MBC PLANKTONIC, MBEC / MIC AND MBEC / MBC RESULTS FOR CANINE OTITIS S. PSEUDINTERMEDIUS, P. AERUGINOSA, E. COLI, P. MIRABILIS, S. CANIS AND M. PACHYDERMATIS ISOLATES FOR COMPOSITION ATABLE 8MBEC, MIC AND MBC PLANKTONIC, MBEC / MIC AND MBEC / MBC RESULTS FOR CANINEOTITIS S. PSEUDINTERMEDIUS, P. AERUGINOSA, E. COLI, P. MIRABILIS, S. CANIS AND M. PACHYDERMATIS ISOLATES FOR N -ACETYLCYSTEINE (NAC)TABLE 9MBEC, MIC AND MBC PLANKTONIC, MBEC / MIC AND MBEC / MBC RESULTS FOR CANINE OTITIS S. PSEUDINTERMEDIUS, P. AERUGINOSA, E. COLI, P. MIRABILIS, S. CANIS AND M.PACHYDERMATIS ISOLATES FOR TRIS-EDTA

[0218] Further antibiofilm studies were conducted using Composition B (containing 1 g / L PHMB; prepared in accordance with Example 1) in comparison to compositions comprising NAC (20 g / L) and Tris-EDTA (1.2 g / L). Five reference strains (B. cepacia, S. aureus, E. coll, S. pseudintermedius and P. aeruginosa), five Pseudomonas canine clinical isolates and five Staphylococcus canine clinical isolates were selected for testing and the effect of the test compositions was assessed using the microtiter plate assay with crystal violet staining as described in Christensen etal. (1985) Journal of Clinical Microbiology, 22(6): 996-1006. Crystal violet staining in the microtiter plate method showed similar antibiofilm activity of Composition A (containing 2 g / L PHMB) and Composition B (containing 1 g / L PHMB). The two formulations substantially inhibited the growth of biofilm bacteria and dispersed biofilms up to 1 / 16 dilution for all the examined strains (reference strains and clinical isolates) (refer to Figures 4-6). However, the NAC and Tris-EDTA compositions required lower dilutions of up to one half to obtain comparable killing effects. Re-growth of planktonic microorganisms was not observed after exposure to Compositions A and B (Figure 7-9).

[0219] A time kill anti-biofilm assay against two Gram-negative bacteria exposed to Compositions A, B and C (prepared in accordance with Example 1) containing differentPHMB concentrations (2 g / L, 1 g / L and 0.5 g / L PHMB, respectively) was performed to assess the least amount of time that the formulations can inhibit strong biofilms. In brief, pure cultures from agar plates were inoculated into Mueller Hinton broth and allowed to grow overnight at 37°C with shaking at 200 rpm. The following day the optical density of the inoculum was set to 0.1 (0.5 MacFarland standard) and diluted to 1 : 100 in fresh medium. 200 pL of inocula was added to individual wells of a sterile 96 well plate. The plates were incubated at 37°C for 24h followed by recording optical density at 620 nm using Tecan plate reader and three washings with sterile water. Dilutions of Composition A, B or C, NAC (20 g / L) and Tris-EDTA (39.04 g / L) and control samples (200 pL) were transferred to each well and the plates were placed back in the incubator for another 24h. Turbidity was recorded at 620 nm using Tecan plate reader. The wells were washed three times with sterile water and biofilms were fixed by heating at 60°C for Ih. 200 pL of crystal violet (CV) solution (~0.5%) was added to each well and incubated for 15 minutes in the dark. The plates were rinsed four times with sterile water and air-dried. 100 pL of acetic acid 30% (v / v) was added to each well to solubilise the CV. The absorbance was read at 570 nm using Tecan plate reader. The experiments were conducted in duplicate and repeated twice on different days. The experiment had the following controls: (i) positive control: untreated bacteria (bacteria and media); (ii) negative control: media only.

[0220] The three formulations showed the ability to inhibit established biofilms of Klebsiella and P. mirabilis clinical isolates at 30 mins, 1.5 hr, 3 hr and 24 hr contact times (refer to Figures 10-14). Results showed a low OD570 of Compositions A, B and C which were consistent all throughout the time points (refer to Figures 10 and 11). Regrowth of planktonic microorganisms was not observed after exposure to Compositions A, B and C (refer to Figures 12 and 13). In comparison, the NAC (20 g / L) and Tris-EDTA (39.04 g / L) formulations showed a higher OD570 nm than Compositions A, B and C, which indicates a lower inhibitory effect of NAC and Tris-EDTA in the established bacterial biofilms. The positive control, which is the biofilm without any treatment, showed an established biofilm.EXAMPLE 3 - EFFICACY OF COMPOSITIONS AGAINST BURKHOLDERIA SPP., SERRATIA SPP., ENTEROCOCCUS SPP, AND CORYNEBACTERIUM SPP,

[0221] Gram-negative bacteria, particularly Burkholderia species such as B. cepacia, are ubiquitous bacteria that are increasingly associated with human and animal infection. This bacterium has the ability for multi-antibiotic resistance. Efficacy of Compositions A, B and C (prepared in accordance with Example 1) were tested in vitro against Burkholderia strains using a time-kill assay (refer to Figures 15-17). The time-kill assay was based on the Standard Guide for Assessment of Antimicrobial Activity using a Time-Kill Procedure. The efficacy of Compositions A, B and C and the comparative NAC (20 g / L) and Tris-EDTA (39.04 g / L) compositions were assessed against different bacterialisolates. The time-kill protocol was performed at different time-points including 10 secs, 30 secs and 60 sec. At each designated time, the test composition was inactivated by taking samples and diluting them up to 10'6into Tryptic Soy Broth with Lecithin and Tween 80 (TSBLT, Edward, Australia) media. The 10'4, 10'5, and 10'6dilutions were used to plate 100 pL onto Mueller Hinton agar for bacterial isolates. The plates were incubated at 37°C for 24 h for bacterial microbial counting.

[0222] Impressive results were obtained showing 100% killing at 10 seconds contact time using Compositions A, B and C containing different PHMB concentrations against planktonic B. cenocepacia (ATCC BAA-245) and B. multivorans (ATCC BAA-247). The comparative NAC and Tris-EDTA compositions were found to be less effective. A more resistant strain, B. cepacia (ATCC 25416), was 100% killed using Compositions A and B at 30 seconds and Composition C at 1 minute. Further dilutions of Compositions A, B and C into 1 / 16 and 1 / 32 were subjected to the time kill planktonic assay, and showed a killing efficacy, but at a lesser rate compared to the 1 / 10 dilution as expected (refer to Figure 16). B. cenocepacia (ATCC BAA-245) can form strong biofilms, and Compositions A, B and C displayed a good inhibitory effect in the established Burkholderia species biofilms (refer to Figure 18). Re-growth of planktonic microorganisms was not observed after exposure to Compositions A, B and C at 1 / 2 and 1 / 5 dilutions (refer to Figure 19). It was also found that preservatives (e.g. parabens) do not contribute to the efficacy of the composition (refer to Figure 17). Compositions A, B and C also showed efficacy against S. marcescens (ATCC 13880) (refer to Figure 20), C. urealyticum and an Enterococcus clinical isolate (refer to Figure 21).EXAMPLE 4 - EFFECT ON ANTIBIOTIC SUSCEPTIBILITY

[0223] The effect of Composition A (prepared in accordance with Example 1) on the antibiotic susceptibility of bacteria was assessed using mixed population bacterial samples obtained from canine clinical swab samples (refer to Figure 22). Broth microdilution was used to determine the MICs of enrofloxacin, neomycin, gentamicin and marbofloxacin for the pre- and post-treated bacterial isolates.Antibiotic preparation

[0224] Cation adjusted Mueller Hinton II broth (BBL) was modified by adding 2,3,5-triphenyltetrazolium chloride (Sigma-Aldrich) at a concentration of 0.5%. Antibiotic concentrations ranging from 0.12 mg / mL to 128 mg / mL for enrofloxacin (Sigma-Aldrich), gentamicin (Sigma-Aldrich) and marbofloxacin (Sigma-Aldrich) and antibiotic concentrations ranging from 0.5 mg / mL to 512 mg / mL for neomycin (Sigma-Aldrich) were prepared using doubling dilutions in the modified Muller Hinton II broth. 100 mL of each antibiotic dilution was added to sterile 96-well microtitre plates (Technoplas).Determination of minimal inhibitory concentrations

[0225] Each sample [Composition A or Tris-EDTA suspension (39.04 g / L)] was diluted by 1 in 10, using TSBLT (Edward, Australia). 100 mL of each diluted sample was added to the antibiotic containing wells in triplicate. The wells were incubated for 16-18hrs at 35-37°C. The wells were observed for growth by looking for the development of a pink pigment. The MIC was the lowest concentration of antibiotic that showed no pink pigment.

[0226] Composition A treatment enhanced the antibiotic susceptibility of mixed population bacterial samples using enrofloxacin, gentamicin and marbofloxacin antibiotics (refer to Figure 22). However, there was no statistically significant change in antibiotic susceptibility in the mixed bacteria population before and after treatment with Tris-EDTA.EXAMPLE 5 - EFFICACY OF COMPOSITIONS AGAINST P. AERUGINOSA, S. PSEUDINTERMEDIUS AND M. PACHYDERMATIS BIOFILMS IN COMPARISON TO A COMPOSITION COMPRISING 0.15% CHLORHEXIDINE DIGLUCONATE AND TRIS-EDTA

[0227] The efficacy of Composition B (prepared in accordance with Example 1) was compared to a composition comprising 0.15% chlorhexidine digluconate and Tris-EDTA (Otodine, Nextmune AB; hereinafter "Comparator Composition").

[0228] Composition B and the Comparator Composition were diluted to have a final concentration of 1 / 2, 1 / 4, 1 / 8, 1 / 16, 1 / 32, 1 / 64 and 1 / 256 using Mueller Hinton broth with 1% glucose for the bacterial assays and SBOT media (Sabouraud Dextrose broth (SDB) supplemented with 2 mL glycerol, 2 mL Tween80, 5 mL Tween40 and 5 mL olive oil per litre) for the M. pachydermatis assay.

[0229] The reference microbial strains used in this study were Pseudomonas aeruginosa (P. aeruginosa) ATCC 27853, Staphylococcus pseudintermedius (S. pseudintermedius) ATCC 49444 and Malassezia pachydermatis (M. pachydermatis) ATCC 14522 from the ATCC. Clinical isolates of P. aeruginosa, S. pseudintermedius and M. pachydermatis from Dermcare-Vet culture collection strains were also tested. Identification of the clinical isolates used in this study was confirmed using Matrix-Assisted Laser Desorption / Ionization-Time of Flight (MALDI-TOF) Mass Spectrometry (University of Adelaide, Roseworthy Veterinary Hospital).

[0230] Bacterial isolates from the frozen stocks (-80°C Freezer) were revived and inoculated onto Tryptic Soy Agar (TSA) plates (Thermofisher, Australia) and incubated at 37°C for 18-24 hrs. M. pachydermatis were revived from the frozen stocks by inoculating onto Sabouraud Dextrose Agar (SDA) plates (Thermofisher, Australia) and incubated for 72 hrs at 37°C.

[0231] The method described by Wilson et al. / 2017) Res Rev J Eng Technol., 6(4) : 1-25 with some modifications was used to determine biofilm production of bacterialstrains. Bacterial strains were grown from frozen stock as above for 18-24 hrs. Cell suspension of McFarland 0.5 was prepared and diluted into 1 / 100. Inoculum (200 pL) was added into 96-well microtiter plate in triplicates and incubated at 37°C for 24 hrs or until good growth of positive control was established. The next day, the cell suspension was taken out and wells were washed 3x with 200 pL lx phosphate-buffered saline (PBS). The microtiter plates were heat fixed for 1 hr at 60°C. Crystal violet staining (0.2%) (200 pL) was performed for 15 mins at room temperature. The wells were washed 4x with sterile purified water and dried for few minutes. The crystal violet was re-solubilised with 30% acetic acid (200 pL) and incubated for 10-15 mins. Re-solubilised sample (100 pL) was transferred to new microtiter plate and absorbance at 570 nm was read using a spectrophotometer. Moderate to strong biofilm producers to be used for efficacy testing were identified using the criteria in Table 6 (refer to Example 2).

[0232] The method described by Conkova et al. (2022) J Fungi, 8(11): 1209 with some modifications was used to determine biofilm production of M. pachydermatis strains. M. pachydermatis were grown from frozen stock as detailed above for 48-72 hrs. Cell suspension of McFarland 2.0 was prepared and diluted into 1 / 10. Inoculum (150 pL) was added into 96-well microtiter plate in triplicates and incubated at 37°C for 24 hrs at 80 rpm to allow fungal adherence to the surface of the plate wells. The next day, the cell suspension was taken out and wells were washed with 150 pL lx PBS. SBOT media (200 pL) (SDB supplemented with 2 mL glycerol, 2 mL Tween80, 5 mL Tween40 and 5 mL olive oil per litre) was added into the wells. Further incubation at 37°C for 72 hrs at 80 rpm was performed. After incubation, the cell suspensions were removed and washed 3x with lx PBS. The microtiter plates were heat fixed for 1 hr at 60°C. Crystal violet staining (0.5%) (200 pL) was performed for 45 mins at room temperature. The wells were washed 4x with sterile purified water and dried for few minutes. The crystal violet was re-solubilised with 30% acetic acid (200 pL) and incubated for 10-15 mins. Re-solubilised sample (100 pL) was transferred to new microtiter plate and absorbance at 570 nm was read using a spectrophotometer. Moderate to strong biofilm producers to be used for efficacy testing were identified using the criteria in Table 6 (refer to Example 2).

[0233] For bacteria, after biofilm formation following 24 hrs incubation, cell suspensions were removed and washed 3x with lx PBS. Several dilutions of Composition B and the Comparator Composition (1 / 2, 1 / 4, 1 / 8, 1 / 16, 1 / 32, 1 / 512) were tested for efficacy in inhibiting biofilms in triplicates. The plates were incubated at 37°C for 24 hrs. The next day, the plates were washed 3x with lx PBS and heat fixed for 1 hr at 60°C. Crystal violet staining and re-solubilisation were performed as detailed above.

[0234] For M. pachydermatis, after biofilm formation for 4 days, cell suspensions were removed and washed 3x with lx PBS. Several dilutions of Composition B and the Comparator Composition (1 / 2, 1 / 4, 1 / 8, 1 / 16, 1 / 32, 1 / 256) were tested for efficacy ininhibiting biofilms in triplicates. The plates were incubated at 37°C for 72 hrs. Subsequently, the plates were washed 3x with lx PBS and heat fixed for 1 hr at 60°C. Crystal violet staining and re-solubilisation were performed as detailed above.

[0235] Out of eleven P. aeruginosa strains, 10 strains were strong biofilm producers using Mueller Hinton broth supplemented with 1% glucose (refer to Table 10). Out of 11 S. pseudintermedius strains, 8 strains were strong biofilm producers using Mueller Hinton broth supplemented with 1% glucose. Mueller Hinton broth was also trialled for bacterial biofilm formation, and similar results were obtained. All 11 M. pachydermatis strains showed strong biofilm formation using SBOT media. SDB with Tween80 and glycerol was also trialled but did not form intact biofilms.TABLE 10BIOFILM FORMATION OF MICROORGANISMS

[0236] Composition B and the Comparator Composition were compared in their efficacy to inhibit microbial biofilms. The compositions were diluted into 1 / 2, 1 / 4, 1 / 8, 1 / 16, 1 / 32, 1 / 64 and 1 / 256 and biofilm growth (OD570) was assessed after 24 hours.

[0237] Composition B and the Comparator Composition were found to inhibit P. aeruginosa biofilm growth even at diluted concentrations of 1 / 2, 1 / 4, 1 / 8, 1 / 16 and 1 / 32, while less diluted concentrations of the products were needed for more resistant P. aeruginosa isolates (1 / 2, 1 / 4 and 1 / 8). Composition B and the Comparator Composition inhibited S. pseudintermedius biofilm growth at diluted concentrations from 1 / 2, 1 / 4, 1 / 8, 1 / 16 and 1 / 32. The two compositions had similar efficacy against these strains.

[0238] Composition B and the Comparator Composition were found to also inhibit M. pachydermatis biofilm growth, with Composition B having superior efficacy in all tested M. pachydermatis isolates (refer to Figure 23).

[0239] The disclosure of every patent, patent application, and publication cited herein is hereby incorporated herein by reference in its entirety.

[0240] The citation of any reference herein should not be construed as an admission that such reference is available as "Prior Art" to the instant application.

[0241] Throughout the specification the aim has been to describe the preferred embodiments of the invention without limiting the invention to any one embodiment or specific collection of features. Those of skill in the art will therefore appreciate that, in light of the instant disclosure, various modifications and changes can be made in the particular embodiments exemplified without departing from the scope of the present invention. All such modifications and changes are intended to be included within the scope of the appended claims.EMBODIMENTS

[0242] Exemplary embodiments include, but are not limited to:1. A method of disrupting or eradicating a biofilm, comprising contacting the biofilm with a composition comprising poly(hexamethylene) biguanide (PHMB) or a pharmaceutically or veterinary acceptable salt thereof, a chelating agent and a buffering agent.2. The method according to embodiment 1, wherein the biofilm comprises at least one bacterium selected from the group consisting of Staphylococcus pseud intermedi us, Pseudomonas aeruginosa, Escherichia coli, Proteus mirabilis, Streptococcus canis, Burkholderia cepacia, Burkholderia cenocepacia, Burkholderia multivorans, Staphylococcus aureus, Klebsiella oxytoca, Klebsiella pneumoniae, Klebsiella aerogenes, Enterococcus faecalis, Enterococcus canintestini, Corynebacterium auriscanis, Corynebacterium amycolatum and Serratia marcescens.3. The method according to embodiment 2, wherein the bacterium is resistant to at least one antibiotic.4. The method according to any one of embodiments 1-3, wherein the biofilm comprises Malassezia pachydermatis.5. A method of treating or inhibiting the development of an infection caused by a bacterium selected from the group consisting of Burkholderia spp., Serratia spp., Enterococcus spp. and Corynebacterium spp. in a subject, comprising administering a composition comprising PHMB or a pharmaceutically or veterinary acceptable salt thereof, a chelating agent and a buffering agent to the subject.6. The method according to embodiment 5, wherein the bacterium is resistant to one or more antibiotics.7. A method of conferring antibiotic susceptibility to a resistant bacterium, comprising contacting the bacterium with a composition comprising PHMB or a pharmaceutically or veterinary acceptable salt thereof, a chelating agent and a buffering agent, wherein the bacterium is selected from the group consisting of Burkholderia spp., Serratia spp., Enterococcus spp. and Corynebacterium spp..8. A method of increasing the susceptibility of a bacterium to an antibiotic, comprising contacting the bacterium with a composition comprising PHMB or apharmaceutically or veterinary acceptable salt thereof, a chelating agent and a buffering agent, wherein the bacterium is selected from the group consisting of Burkholderia spp., Serratia spp., Enterococcus spp. and Corynebacterium spp..9. The method according to any one of embodiments 5-8, wherein the bacterium is selected from the group consisting of Burkholderia spp., Serratia spp. and Corynebacterium spp..10. The method according to any one of embodiments 5-8, wherein the bacterium is selected from the group consisting of Burkholderia spp. and Serratia spp..11. The method according to embodiment 10, wherein the bacterium is B. cepacia, B. cenocepacia or B. multivorans.12. The method according to embodiment 10, wherein the bacterium is S. marcescens.13. The method according to any one of embodiments 5-8, wherein the bacterium is E. faecalis or E. canintestini.14. The method according to any one of embodiments 5-9, wherein the bacterium is C. auriscanis, C. amycolatum or Corynebacterium urealyticum.15. The method according to any one of embodiments 5-14, wherein the bacterium is in the form of a biofilm.16. The method according to any one of embodiments 1-15, wherein the chelating agent is glycinate, iminodiacetic acid, nitrilotriacetic acid, nitrilotripropionic acid, ethylenediamine tetraacetic acid (EDTA), diethylenetriamine pentaacetic acid, ethylene glycol-bis(P-aminoethyl ether)- / V, / V, / V', / V'-tetraacetic acid, l,2-bis(o- aminophenoxy)ethane- / V, / V, / V', / V / -tetraacetic acid, l,4,7-triazacyclononane-l,4,7-triacetic acid, 2,2',2",2"'-(l,4,7,10-tetraazacyclododecane-l,4,7,10-tetrayl)tetraacetic acid, nicotimamine, ethylenediamine- / V, / V'-bis(2-hydroxyphenylacetic acid), ethylenediamine disuccinic acid, 2-hydroxyethyl-ethylenediamine-triacetic acid, 1,6-diamino- hexamethylene-tetraacetic acid, 1,2-diamino-cyclohexane tetraacetic acid, O,O9-bis(2- aminoethyl)-ethyleneglycol-tetraacetic acid, 1,3-diaminopropane-tetraacetic acid, N,N- bis(2-hydroxybenzyl)ethylenediamine- / V, / V-diacetic acid, ethylenediamine- / V, / V9-diacetic acid, ethylenediamine- / V, / V9-dipropionic acid, triethylenetetraamine hexaacetic acid, 7,19,30-trioxa-l,4,10,13,16,22,27,33-octaazabicyclo[ll,ll,ll]pentatriacontane (O-bis- tren), ethylenediamine- / V, / V9-bis(methylenephosphonic acid), iminodiacetic acid, N,N- bis(2-hydroxyethyl)glycine, l,3-diamino-2-hydroxypropane-tetraacetic acid, 1,2- diaminopropane-tetraacetic acid, ethylenediamine-tetrakis(methylenephosphonic acid), N- (2-hydroxyethyl)iminodiacetic acid, triethylenetetramine-hexaacetic acid, deferoxamine, dimercaprol, citrate, penicillamine, etidronate, a macrocyclic polyether, polyaspartic acid, methylglycinediacetic acid, glutamic diacetic acid, gluconic acid, or a pharmaceutically or veterinary acceptable salt of any of the foregoing.17. The method according to embodiment 16, wherein the chelating agent is EDTA or a pharmaceutically or veterinary acceptable salt thereof.18. The method according to any one of embodiments 1-17, wherein the chelating agent is selected from the group consisting of disodium EDTA, trisodium EDTA, tetrasodium EDTA, dipotassium EDTA, tripotassium EDTA, lithium EDTA, dilithium EDTA, ammonium EDTA, diammonium EDTA and calcium disodium EDTA.19. The method according to embodiment 18, wherein the chelating agent is disodium EDTA.20. The method according to any one of embodiments 1-19, wherein the buffering agent is tris(hydroxymethyl)aminomethane (Tris), triethylamine, triethylenetetramine, tetraethylethylenediamine, tetramethylenediamine, / V, / V'-diethyl- / V, / V'-bis(sulfopropyl)- ethylenediamine, / V, / V'-diethylpiperazine, piperazine- / V, / V'-bis(alkylsulfonic acids), ( / V-morpholino)alkylsulfonic acids, 2-aminoethanol, 2-amino-2-methyl-l-propanol, triethanolamine, 2-amino-2-methyl-l,3-propanediol, bis-(2-hydroxyethyl)imino- tris(hydroxymethyl)methane, 2-dimethylamino-2-methyl-l-propanol, 2-amino-2-ethyl- 1,3-propanediol, l,3-bis(tris[hydroxymethyl]methylamino)propane, / V, / V-bis(2- hydroxyethyl)-2-aminoethanesulfonic acid, / V-[tris(hydroxymethyl)methyl]-3- aminopropanesulfonic acid, / V, / V-bis(2-hydroxyethyl)glycine, / V, / V-bis(2- hydroxyethyl)taurine, diethanolamine, / V-tris(hydroxymethyl)methylglycine or a pharmaceutically or veterinary acceptable salt of any of the foregoing.21. The method according to embodiment 20, wherein the buffering agent is Tris or a pharmaceutically or veterinary acceptable salt thereof.22. The method according to any one of embodiments 1-21, wherein the composition comprises poly(hexamethylene) biguanide HCI.23. The method according to any one of embodiments 1-22, wherein the composition comprises PHMB or a pharmaceutically or veterinary acceptable salt thereof in an amount in the range of from about 0.025% to about 0.2% w / v.24. The method according to embodiment 23, wherein the composition comprises PHMB or a pharmaceutically or veterinary acceptable salt thereof in an amount in the range of from about 0.05% to about 0.15% w / v.25. The method according to embodiment 24, wherein the composition comprises PHMB or a pharmaceutically or veterinary acceptable salt thereof in an amount of about 0.05% w / v or about 0.1% w / v.26. The method according to any one of embodiments 1-25, wherein the composition comprises the chelating agent in an amount in the range of from about 0.1% to about 0.2% w / v.27. The method according to embodiment 26, wherein the composition comprises the chelating agent in an amount of about 0.12% w / v.28. The method according to any one of embodiments 1-27, wherein the composition comprises the buffering agent in an amount in the range of from about 0.5% to about 0.8% w / v.29. The method according to embodiment 28, wherein the composition comprises the buffering agent in an amount of about 0.605% w / v.30. The method according to any one of embodiments 1-29, wherein the composition further comprises a rheology modifier.31. The method according to any one of embodiments 1-30, wherein the composition further comprises an aqueous carrier.32. The method according to any one of embodiments 1-31, wherein the composition comprises PHMB or a pharmaceutically or veterinary acceptable salt thereof and the chelating agent in a weight ratio of from about 1 : 1 to about 1 :4.33. The method according to embodiment 32, wherein the weight ratio is from about 1 : 1.2 to about 1:2.4.34. A composition comprising PHMB or a pharmaceutically or veterinary acceptable salt thereof, a chelating agent and a buffering agent for use in disrupting or eradicating a biofilm.35. The composition for use according to embodiment 34, wherein the biofilm comprises at least one bacterium selected from the group consisting of Staphylococcus pseudintermedius, Pseudomonas aeruginosa, Escherichia coli, Proteus mirabilis, Streptococcus canis, Burkholderia cepacia, Burkholderia cenocepacia, Burkholderia multivorans, Staphylococcus aureus, Klebsiella oxytoca, Klebsiella pneumoniae, Klebsiella aerogenes, Enterococcus faecalis, Enterococcus canintestini, Corynebacterium auriscanis, Corynebacterium amycolatum and Serratia marcescens.36. The composition for use according to embodiment 35, wherein the bacterium is resistant to at least one antibiotic.37. The composition for use according to any one of embodiments 34-36, wherein the biofilm comprises Malassezia pachydermatis.38. A composition comprising PHMB or a pharmaceutically or veterinary acceptable salt thereof, a chelating agent and a buffering agent for use in treating or inhibiting the development of an infection caused by a bacterium selected from the group consisting of Burkholderia spp., Serratia spp., Enterococcus spp. and Corynebacterium spp. in a subject.39. The composition for use according to embodiment 38, wherein the bacterium is resistant to one or more antibiotics.40. A composition comprising PHMB or a pharmaceutically or veterinary acceptable salt thereof, a chelating agent and a buffering agent for use in conferring antibiotic susceptibility to a resistant bacterium, wherein the bacterium is selected from the group consisting of Burkholderia spp., Serratia spp., Enterococcus spp. and Corynebacterium spp..41. A composition comprising PHMB or a pharmaceutically or veterinary acceptable salt thereof, a chelating agent and a buffering agent for use in increasing the susceptibility of a bacterium to an antibiotic, wherein the bacterium is selected from the group consisting of Burkholderia spp., Serratia spp., Enterococcus spp. and Corynebacterium spp..42. The composition for use according to any one of embodiments 38-41, wherein the bacterium is selected from the group consisting of Burkholderia spp., Serratia spp. and Corynebacterium spp..43. The composition for use according to any one of embodiments 38-41, wherein the bacterium is selected from the group consisting of Burkholderia spp. and Serratia spp..44. The composition for use according to embodiment 43, wherein the bacterium is B. cepacia, B. cenocepacia or B. multivorans.45. The composition for use according to embodiment 43, wherein the bacterium is S. marcescens.46. The composition for use according to any one of embodiments 38-41, wherein the bacterium is E. faecalis or E. canintestini.47. The composition for use according to any one of embodiments 38-42, wherein the bacterium is C. auriscanis, C. amycolatum or Corynebacterium urealyticum.48. The composition for use according to any one of embodiments 38-47, wherein the bacterium is in the form of a biofilm.49. The composition for use according to any one of embodiments 34-48, wherein the chelating agent is glycinate, iminodiacetic acid, nitrilotriacetic acid, nitrilotripropionic acid, ethylenediamine tetraacetic acid (EDTA), diethylenetriamine pentaacetic acid, ethylene glycol-bis(0-aminoethyl ether)- / V, / V, / V', / V'-tetraacetic acid, l,2-bis(o- aminophenoxy)ethane- / V, / V, / V', / V / -tetraacetic acid, l,4,7-triazacyclononane-l,4,7-triacetic acid, 2,2',2",2"'-(l,4,7,10-tetraazacyclododecane-l,4,7,10-tetrayl)tetraacetic acid, nicotimamine, ethylenediamine- / V, / V'-bis(2-hydroxyphenylacetic acid), ethylenediamine disuccinic acid, 2-hydroxyethyl-ethylenediamine-triacetic acid, 1,6-diamino- hexamethylene-tetraacetic acid, 1,2-diamino-cyclohexane tetraacetic acid, O,O9-bis(2- aminoethyl)-ethyleneglycol-tetraacetic acid, 1,3-diaminopropane-tetraacetic acid, N,N- bis(2-hydroxybenzyl)ethylenediamine- / V, / V-diacetic acid, ethylenediamine- / V, / V9-diacetic acid, ethylenediamine- / V, / V9-dipropionic acid, triethylenetetraamine hexaacetic acid, 7,19,30-trioxa-l,4,10,13,16,22,27,33-octaazabicyclo[ll,ll,ll]pentatriacontane (O-bis- tren), ethylenediamine- / V, / V9-bis(methylenephosphonic acid), iminodiacetic acid, N,N- bis(2-hydroxyethyl)glycine, l,3-diamino-2-hydroxypropane-tetraacetic acid, 1,2- diaminopropane-tetraacetic acid, ethylenediamine-tetrakis(methylenephosphonic acid), N- (2-hydroxyethyl)iminodiacetic acid, triethylenetetramine-hexaacetic acid, deferoxamine, dimercaprol, citrate, penicillamine, etidronate, a macrocyclic polyether, polyaspartic acid, methylglycinediacetic acid, glutamic diacetic acid, gluconic acid, or a pharmaceutically or veterinary acceptable salt of any of the foregoing.50. The composition for use according to 49, wherein the chelating agent is EDTA or a pharmaceutically or veterinary acceptable salt thereof.51. The composition for use according to any one of embodiments 34-50, wherein the chelating agent is selected from the group consisting of disodium EDTA, trisodium EDTA, tetrasodium EDTA, dipotassium EDTA, tripotassium EDTA, lithium EDTA, dilithium EDTA, ammonium EDTA, diammonium EDTA and calcium disodium EDTA.52. The composition for use according to embodiment 51, wherein the chelating agent is disodium EDTA.53. The composition for use according to any one of embodiments 34-52, wherein the buffering agent is tris(hydroxymethyl)aminomethane (Tris), triethylamine, triethylenetetramine, tetraethylethylenediamine, tetramethylenediamine, / V, / V'-diethyl- / V, / V'-bis(sulfopropyl)-ethylenediamine, / V, / V'-diethylpiperazine, piperazine- / V, / V'- bis(alkylsulfonic acids), ( / V-morpholino)alkylsulfonic acids, 2-aminoethanol, 2-amino-2- methyl-l-propanol, triethanolamine, 2-amino-2-methyl-l,3-propanediol, bis-(2- hydroxyethyl)imino-tris(hydroxymethyl)methane, 2-dimethylamino-2-methyl-l-propanol, 2-amino-2-ethyl-l,3-propanediol, l,3-bis(tris[hydroxymethyl]methylamino)propane, N,N- bis(2-hydroxyethyl)-2-aminoethanesulfonic acid, / V-[tris(hydroxymethyl)methyl]-3- aminopropanesulfonic acid, / V, / V-bis(2-hydroxyethyl)glycine, / V, / V-bis(2- hydroxyethyl)taurine, diethanolamine, / V-tris(hydroxymethyl)methylglycine or a pharmaceutically or veterinary acceptable salt of any of the foregoing.54. The composition for use according to embodiment 53, wherein the buffering agent is Tris or a pharmaceutically or veterinary acceptable salt thereof.55. The composition for use according to any one of embodiments 34-54, wherein the composition comprises poly(hexamethylene) biguanide HCI.56. The composition for use according to any one of embodiments 34-55, wherein the composition comprises PHMB or a pharmaceutically or veterinary acceptable salt thereof in an amount in the range of from about 0.025% to about 0.2% w / v.57. The composition for use according to embodiment 56, wherein the composition comprises PHMB or a pharmaceutically or veterinary acceptable salt thereof in an amount in the range of from about 0.05% to about 0.15% w / v.58. The composition for use according to embodiment 57, wherein the composition comprises PHMB or a pharmaceutically or veterinary acceptable salt thereof in an amount of about 0.05% w / v or about 0.1% w / v.59. The composition for use according to any one of embodiments 34-58, wherein the composition comprises the chelating agent in an amount in the range of from about 0.1% to about 0.2% w / v.60. The composition for use according to embodiment 59, wherein the composition comprises the chelating agent in an amount of about 0.12% w / v.61. The composition for use according to any one of embodiments 34-60, wherein the composition comprises the buffering agent in an amount in the range of from about 0.5% to about 0.8% w / v.62. The composition for use according to embodiment 61, wherein the composition comprises the buffering agent in an amount of about 0.605% w / v.63. The composition for use according to any one of embodiments 34-62, wherein the composition further comprises a rheology modifier.64. The composition for use according to any one of embodiments 34-63, wherein the composition further comprises an aqueous carrier. 65. The composition for use according to any one of embodiments 34-64, wherein the composition comprises PHMB or a pharmaceutically or veterinary acceptable salt thereof and the chelating agent in a weight ratio of from about 1: 1 to about 1 :4.66. The composition for use according to embodiment 65, wherein the weight ratio is from about 1: 1.2 to about 1 :2.4.

Claims

THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:

1. A method of disrupting or eradicating a biofilm, comprising contacting the biofilm with a composition comprising poly(hexamethylene) biguanide (PHMB) or a pharmaceutically or veterinary acceptable salt thereof, a chelating agent and a buffering agent.

2. The method according to claim 1, wherein the biofilm comprises at least one bacterium selected from the group consisting of Staphylococcus pseudintermedius, Pseudomonas aeruginosa, Escherichia coli, Proteus mirabilis, Streptococcus canis, Burkholderia cepacia, Burkholderia cenocepacia, Burkholderia multivorans, Staphylococcus aureus, Klebsiella oxytoca, Klebsiella pneumoniae, Klebsiella aerogenes, Enterococcus faecalis, Enterococcus canintestini, Corynebacterium auriscanis, Corynebacterium amycolatum and Serratia marcescens.

3. The method according to claim 2, wherein the bacterium is resistant to at least one antibiotic.

4. The method according to any one of claims 1-3, wherein the biofilm comprises Malassezia pachydermatis.

5. A method of treating or inhibiting the development of an infection caused by a bacterium selected from the group consisting of Burkholderia spp., Serratia spp., Enterococcus spp. and Corynebacterium spp. in a subject, comprising administering a composition comprising PHMB or a pharmaceutically or veterinary acceptable salt thereof, a chelating agent and a buffering agent to the subject.

6. The method according to claim 5, wherein the bacterium is resistant to one or more antibiotics.

7. A method of conferring antibiotic susceptibility to a resistant bacterium, comprising contacting the bacterium with a composition comprising PHMB or a pharmaceutically or veterinary acceptable salt thereof, a chelating agent and a buffering agent, wherein the bacterium is selected from the group consisting of Burkholderia spp., Serratia spp., Enterococcus spp. and Corynebacterium spp..

8. A method of increasing the susceptibility of a bacterium to an antibiotic, comprising contacting the bacterium with a composition comprising PHMB or a pharmaceutically or veterinary acceptable salt thereof, a chelating agent and a buffering agent, wherein the bacterium is selected from the group consisting of Burkholderia spp., Serratia spp., Enterococcus spp. and Corynebacterium spp..

9. The method according to any one of claims 5-8, wherein the bacterium is selected from the group consisting of Burkholderia spp., Serratia spp. and Corynebacterium spp..

10. The method according to any one of claims 5-8, wherein the bacterium is selected from the group consisting of Burkholderia spp. and Serratia spp..

11. The method according to claim 10, wherein the bacterium is B. cepacia,B. cenocepacia or B. multivorans or S. marcescens.

12. The method according to any one of claims 5-8, wherein the bacterium isC. auriscanis, C. amycolatum or Corynebacterium urealyticum.

13. The method according to any one of claims 5-12, wherein the bacterium is in the form of a biofilm.

14. The method according to any one of claims 1-13, wherein the chelating agent is glycinate, iminodiacetic acid, nitrilotriacetic acid, nitrilotripropionic acid, ethylenediamine tetraacetic acid (EDTA), diethylenetriamine pentaacetic acid, ethylene glycol-bis(0-aminoethyl ether)- / V, / V, / V', / V'-tetraacetic acid, l,2-bis(o- aminophenoxy)ethane- / V, / V, / V / , / V / -tetraacetic acid, l,4,7-triazacyclononane-l,4,7- triacetic acid, 2,2',2",2"'-(l,4,7,10-tetraazacyclododecane-l,4,7,10- tetrayl)tetraacetic acid, nicotimamine, ethylenediamine- / V, / V'-bis(2- hydroxyphenylacetic acid), ethylenediamine disuccinic acid, 2-hydroxyethyl- ethylenediamine-triacetic acid, 1,6-diamino-hexamethylene-tetraacetic acid, 1,2- diamino-cyclohexane tetraacetic acid, O,O9-bis(2-aminoethyl)-ethyleneglycol- tetraacetic acid, 1,3-diaminopropane-tetraacetic acid, / V, / V-bis(2- hydroxybenzyl)ethylenediamine- / V, / V-diacetic acid, ethylenediamine- / V, / V9-diacetic acid, ethylenediamine- / V, / V9-dipropionic acid, triethylenetetraamine hexaacetic acid, 7,19,30-trioxa-l,4,10,13,16,22,27,33-octaazabicyclo[ll,ll,ll]pentatriacontane (O-bis-tren), ethylenediamine- / V, / V9-bis(methylenephosphonic acid), iminodiacetic acid, / V, / V-bis(2-hydroxyethyl)glycine, l,3-diamino-2-hydroxypropane-tetraacetic acid, 1,2-diaminopropane-tetraacetic acid, ethylenediamine- tetrakis(methylenephosphonic acid), / V-(2-hydroxyethyl)iminodiacetic acid, triethylenetetramine-hexaacetic acid, deferoxamine, dimercaprol, citrate, penicillamine, etidronate, a macrocyclic polyether, polyaspartic acid, methylglycinediacetic acid, glutamic diacetic acid, gluconic acid, or a pharmaceutically or veterinary acceptable salt of any of the foregoing.

15. The method according to claim 14, wherein the chelating agent is disodium EDTA.

16. The method according to any one of claims 1-15, wherein the buffering agent is tris(hydroxymethyl)aminomethane (Tris), triethylamine, triethylenetetramine, tetraethylethylenediamine, tetramethylenediamine, N,N'~ diethyl- / V, / V'-bis(sulfopropyl)-ethylenediamine, / V, / V'-diethylpiperazine, piperazine- / V, / V'-bis(alkylsulfonic acids), ( / V-morpholino)alkylsulfonic acids, 2-aminoethanol, 2- amino-2-methyl-l-propanol, triethanolamine, 2-amino-2-methyl-l,3-propanediol, bis-(2-hydroxyethyl)imino-tris(hydroxymethyl)methane, 2-dimethylamino-2- methyl-l-propanol, 2-amino-2-ethyl-l,3-propanediol,l,3-bis(tris[hydroxymethyl]methylamino)propane, / V, / V-bis(2-hydroxyethyl)-2- aminoethanesulfonic acid, / V-[tris(hydroxymethyl)methyl]-3-aminopropanesulfonic acid, / V, / V-bis(2-hydroxyethyl)glycine, / V, / V-bis(2-hydroxyethyl)taurine, diethanolamine, / V-tris(hydroxymethyl)methylglycine or a pharmaceutically or veterinary acceptable salt of any of the foregoing.

17. The method according to claim 16, wherein the buffering agent is Tris or a pharmaceutically or veterinary acceptable salt thereof.

18. The method according to any one of claims 1-17, wherein the composition comprises poly(hexamethylene) biguanide HCI.

19. The method according to any one of claims 1-18, wherein the composition comprises PHMB or a pharmaceutically or veterinary acceptable salt thereof in an amount in the range of from about 0.025% to about 0.2% w / v, or about 0.05% to about 0.15% w / v.

20. The method according to claim 19, wherein the composition comprises PHMB or a pharmaceutically or veterinary acceptable salt thereof in an amount of about 0.05% w / v or about 0.1% w / v.

21. The method according to any one of claims 1-20, wherein the composition comprises the chelating agent in an amount in the range of from about 0.1% to about 0.2% w / v.

22. The method according to any one of claims 1-21, wherein the composition comprises the buffering agent in an amount in the range of from about 0.5% to about 0.8% w / v.

23. The method according to any one of claims 1-22, wherein the composition further comprises a rheology modifier.

24. The method according to any one of claims 1-23, wherein the composition further comprises an aqueous carrier.

25. The method according to any one of claims 1-24, wherein the composition comprises PHMB or a pharmaceutically or veterinary acceptable salt thereof and the chelating agent in a weight ratio of from about 1: 1 to about 1:4 or about 1 : 1.2 to about 1:2.4.

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