175 results about "MICROBIAL CONCENTRATION" patented technology

The invention relates to the technical field of monitoring analysis, and discloses a microplastic degradation process monitoring system based on microbiological treatment, which comprises the following modules: a microbiological culture module for culturing microorganisms in a microplastic degradation process and adjusting a plurality of parameters through an environmental reactor to maintain the activity of the microorganisms; the data monitoring and processing module is used for monitoring and acquiring a plurality of key indexes of the micro-plastics in the degradation liquid in the degradation process through a plurality of sensors, removing and supplementing abnormal data, and finally synchronously uploading non-abnormal data to the cloud through the Internet of Things node; and the intelligent analysis platform comprises a degradation prediction unit and a reporting unit. Through one-way comparison and relevance comparison, abnormal data monitored by the sensor are removed, the microplastic degradation efficiency is predicted by using the living environment of microorganisms, the concentration of the microorganisms and a degradation kinetic model, and the microplastic degradation efficiency can be comprehensively analyzed in combination with multiple parameters during microplastic degradation analysis.

The invention relates to a preparation method and application of recombinant canine lactoferrin and peptide thereof, aiming at codon preference of host cells, canine lactoferrin genes are optimized, the full length of canine lactoferrin and the lactoferrin peptide are successfully expressed by virtue of an escherichia coli expression system, and the recombinant canine lactoferrin and the peptide thereof are identified by virtue of a minimum inhibitory concentration experiment. It is proved that the canine lactoferrin and the peptide thereof have the inhibiting capacity on pathogenic bacteria such as staphylococcus aureus, salmonella typhimurium and staphylococcus pseudointermedius, and the antibacterial activity MIC of the canine lactoferrin on the staphylococcus aureus, the salmonella typhimurium and the staphylococcus pseudointermedius is 1.5 mg / mL; the antibacterial activity MIC of the dog lactoferrin peptide to staphylococcus aureus is equal to 0.75 mg / mL, and the dog lactoferrin peptide shows high antibacterial ability.

The invention relates to an enzyme response antibacterial carbon dot and a preparation method and application thereof.The carbon dot takes a copper-doped carbon dot as a core and is covalently grafted with a hyaluronic acid shell layer through amidation reaction to form a composite nano material Cu-CDs (at) HA, specifically, soluble copper salt and folic acid are subjected to a hydrothermal reaction to obtain the copper-doped carbon dot, carboxyl is activated through EDC / NHS in a buffer system, and the carbon dot is prepared. And performing grafting reaction with hyaluronic acid to obtain a target product. The hyaluronidase-containing antibacterial composition can be specifically degraded and release antibacterial components under the action of hyaluronidase, shows good bacterial responsive bactericidal performance, has the minimum inhibitory concentrations of 8 g / mL and 16 g / mL for staphylococcus aureus and escherichia coli respectively, and has peroxidase-like activity and free radical scavenging capacity. The antibacterial carbon dots can be used for preparing intelligent wound dressings, antibacterial coatings and other biomedical materials, and have the advantages of responsive drug release, efficient antibacterial property and promotion of wound repair.

The invention provides a cooling tower cleaning period decision-making method based on filler layer resistance characteristic online identification, which comprises the following steps: acquiring multi-dimensional time sequence data such as differential pressure, water temperature, conductivity, turbidity and microbial concentration based on a multi-source sensor, and constructing a structured trend characteristic matrix through time synchronization, abnormal value elimination and statistical characteristic extraction; in combination with expert knowledge, constructing a multi-modal combined pollution knowledge graph, and learning pollution factor interaction weights by using a graph neural network to realize causal reasoning of combined pollution mechanisms such as scaling, biological slime and the like; according to the method, an abnormal causal chain path is efficiently matched in a knowledge graph by adopting improved A * search, causes and evolution stages are output, automatic attribution and intelligent cleaning suggestion optimization are realized, and the resistance abnormity diagnosis accuracy and the adaptability of a cleaning strategy are improved by continuously feeding back diagnosis results and dynamically expanding a knowledge graph structure.

The invention relates to the technical field of fan control, and discloses a fan rotating speed adjusting method and system based on a dynamic pollution load. The method comprises the following steps: collecting a target PM2.5 concentration, a target VOC concentration and a target microorganism concentration of each monitoring point, and calculating a comprehensive pollution load index of each monitoring point; traversing boundary critical points in all the monitoring points based on the comprehensive pollution load index and generating a boundary identification vector; the real-time pressure drop of the air inlet side and the air outlet side of the filter element in each fan is collected, and the pressure difference compensation gain is calculated; calculating a target reference rotating speed for all monitoring points in the responsible sector of each fan; and calculating the average pollution load index of the responsible sector of each fan, executing fuzzy reasoning to obtain a rotating speed increment, and generating a PWM duty ratio according to the target reference rotating speed and the rotating speed increment to drive each fan. The technical problems of space pollution response lag and energy consumption imbalance are solved, and the performance of the air purification system is improved.

The invention discloses a modified chitosan-based antibacterial material as well as a preparation method and application thereof, and belongs to the technical field of antibacterial materials. The ciprofloxacin grafted quaternized chitosan is successfully synthesized by taking the chitosan as a raw material, and the water solubility and the antibacterial ability of the chitosan are effectively improved. The antibacterial diameters of the ciprofloxacin grafted quaternized chitosan prepared by the preparation method disclosed by the invention on escherichia coli and staphylococcus aureus are respectively 35.34 to 39.06 mm and 40.45 to 44.51 mm, and the minimum MIC (Minimum Inhibitory Concentration) and MBC (Minimum Mass Chitosan) can reach 0.0005 mg / mL. In addition, the antibacterial material has an obvious inhibition effect on colletotrichum gloeosporioides and aspergillus niger, and the highest antifungal rates respectively reach 53.81 + / -2.17% and 54.88 + / -1.3%. Compared with the raw materials, the antibacterial ability is greatly improved, and the grafted and modified composite material is environment-friendly and can be used for antibacterial food packaging materials.

The invention provides a medical disinfection parameter control method and a sterilization device, and relates to the technical field of disinfection robotics.The method comprises the steps that microorganism types and microorganism concentrations are rendered to a to-be-disinfected three-dimensional area, and a three-dimensional target space is constructed; performing simulation modeling according to the disinfection attribute data and the three-dimensional target space to generate a disinfection twinborn model; carrying out disinfection scheme optimization by using the disinfection twinborn model and by taking meeting of an expected disinfection index as a constraint, so as to obtain an optimized disinfection scheme; and performing disinfection effect influence analysis according to the environment temperature and the environment humidity, and generating disinfection influence deviation to compensate the optimized disinfection scheme so as to obtain an optimal disinfection scheme. By means of the control method, the technical problems that according to an existing disinfection robot control method, due to the fact that a matched disinfection scheme cannot be set according to the state of the to-be-disinfected area, excessive disinfection or insufficient disinfection is likely to occur, and the area disinfection quality is poor can be solved, and the effects of improving the disinfection quality and efficiency and saving disinfection resources can be achieved.

The invention relates to the technical field of medicines, and particularly discloses application of a Xinjiang medicine mulberry extract in preparation of a medicine for treating or preventing periapical periodontitis, which is technically characterized in that the Xinjiang medicine mulberry extract is found and proved to have a remarkable inhibition effect on periapical periodontitis key pathogenic bacterium enterococcus faecalis for the first time, the minimum inhibitory concentration (MIC) is 0.604 mg / mL, and the Xinjiang medicine mulberry extract has a remarkable inhibition effect on the periapical periodontitis key pathogenic bacterium enterococcus faecalis. The minimum bactericidal concentration (MBC) is 1.875 mg / mL, and a biological membrane can be effectively inhibited and removed; in-vivo experiments of a rat periapical periodontitis model prove that the extract can remarkably reduce the number of bacteria in root canals and relieve periapical bone destruction, the curative effect is equivalent to that of calcium hydroxide, and the extract is non-toxic to main organs and high in biocompatibility. The invention provides a new candidate and a clear technical scheme for developing an efficient and low-toxicity natural plant source root canal disinfectant.

The present invention relates to a method for screening compounds for bactericidal activity using thermostable luciferase and based on a real-time bioluminescence measurement. The present invention further relates to a method for determining the sensitivity of a bacterial sample originating from a subject suffering from a bacterial infection to a group of known antibiotics and to a method for assessing the minimum inhibitory concentration (MIC) of a bactericidal compound.

The invention belongs to the technical field of medical chemistry, and discloses a 5-O-carbon mould amine tylosin lactone derivative with a double-target combined antibacterial effect as well as a preparation method and application of the 5-O-carbon mould amine tylosin lactone derivative. The derivative is a compound as shown in a formula I, and pharmaceutically acceptable salt, eutectic, tautomer, polymorphic substance, solvate, prodrug or isotope labeled compound thereof. The compound can act on a bacterial ribosome 50S subunit and DNA topoisomerase IV at the same time, and shows an excellent antibacterial effect in an antibacterial activity test, and the minimum inhibitory concentration (MIC) reaches 0.0625 mu g / mL. The compound has the advantages of being high in antibacterial activity, wide in antibacterial spectrum and capable of achieving rapid sterilization, and a new choice is provided for developing drugs with antibacterial activity.

The application discloses application of gynostemma pentaphyllum saponin H combined with azole drugs in preparation of antifungal drugs and the antifungal drugs, and relates to the technical field of antifungal drugs. It is found through systematic in-vitro drug sensitivity test that natural product gynostemma pentaphyllum saponin H combined with specific azole antifungal drugs (especially posaconazole POS) can produce significant synergistic antifungal effect, especially for clinical thorny aspergillus, candida, new cryptococcus and dark fungi. The combination strategy can significantly reduce the minimum inhibitory concentration of azole drugs, reverse drug resistance, and is effective for multi-drug resistant strains (such as candida auris). The application provides an efficient and low-toxicity new combination drug scheme for overcoming the increasingly serious fungal drug resistance problem.

This invention discloses a pharmaceutical composition containing the natural products osthol and berberine, exhibiting synergistic antibacterial and antifungal effects. The effectiveness of osthol in synergistically enhancing the antibacterial activity of berberine was demonstrated through checkerboard minimum inhibitory concentration (MIC) tests, antifungal activity experiments, and in vitro bacterial growth curves. This invention provides a novel application of the combined use of osthol and berberine in antibacterial and antifungal treatments. This composition belongs to the category of traditional Chinese medicine compound preparations, offering a new treatment strategy for the clinical treatment of bacterial and fungal infectious diseases.

The invention discloses application of copper sulfate in inhibition of trichomonad activity, in-vitro tests prove that copper sulfate can induce oxidative stress of trichomonad, interfere with sulfur-containing amino acid metabolism, destroy the structure of trichomonad cells and reduce the active oxygen content and hydrogenase membrane potential of trichomonad bodies, and the minimum inhibition concentration of copper sulfate on trichomonad within 48 hours is 640 micrograms / mL. In-vivo tests prove that copper sulfate is added into drinking water according to the concentration of 500 mu g / mL, and is periodically fed once every 15 days and continuously 4 days each time, so that the number of trichomonad in the oral cavities of laying pigeons of silver-feather king pigeons and young pigeons of white-feather king pigeons can be remarkably reduced, and meanwhile, the quality of pigeon eggs is improved, and the immunity and intestinal microbial flora are improved; the application method provided by the invention is safe, efficient and low in cost, the addition concentration of copper sulfate is easy to control, no drug residue risk exists, and the composition can replace traditional antibiotics such as metronidazole to be used for preventing and treating trichomonad of pigeons, is suitable for a large-scale meat pigeon breeding scene and has a wide application prospect.

This invention discloses an antimicrobial peptide cAMP-1 derived from the intestinal microorganisms of wild rodents and its applications, belonging to the field of biotechnology. The amino acid sequence of the antimicrobial peptide cAMP-1 is shown in SEQ ID NO:1. The antimicrobial peptide cAMP-1 exhibits highly efficient, rapid, and safe antimicrobial activity against Streptococcus suis type II. It significantly inhibits bacterial growth even at low concentrations, with a minimum inhibitory concentration (MIC) of 16 µg / mL. Time-kinetic kinetics results show that the antimicrobial peptide can kill all Streptococcus suis type II within 30 min and 15 min at concentrations of 2×MIC and 4×MIC, respectively. Furthermore, within several times the effective concentration range, the peptide exhibits almost no hemolytic activity and low cytotoxicity within a safe dosage range, demonstrating its promising application as a novel anti-infective candidate drug.

The invention discloses recombinant bacteriophage lyase and application thereof. The amino acid sequence of the recombinant bacteriophage lyase E8-3 is as shown in SEQ ID NO: 43, and an in-vitro minimum inhibitory concentration experiment shows that the recombinant bacteriophage lyase E8-3 has a bacteriostatic effect on helicobacter pylori and acinetobacter baumannii, and particularly has a wide application prospect in the development of anti-helicobacter pylori drugs.

The invention discloses an antibacterial peptide sesquidendrin and an application of the antibacterial peptide sesquidendrin. The invention specifically relates to eight sesquistigma polypeptide compounds. The compounds 1-8 show different degrees of antibacterial activity, the compound 2 has broad-spectrum antibacterial activity, the minimum inhibitory concentration of the compound 2 to staphylococcus aureus ATCC 6538 and bacillus cereus CMCC (B) 63301 reaches 20 [mu] g / mL, and the MIC value of the compound 2 to enterococcus faecium 160119481, salmonella typhimurium CMCC (B) 50071 and salmonella typhimurium CMCC (B) 50115 is 40 [mu] g / mL. As staphylococcus, bacillus, enterococcus and salmonella bacteria are common food-borne pathogenic bacteria which seriously threaten food safety, the compounds 1-8 can be used for preparing novel antibacterial peptides which are applied to the field of food safety preservation.

The invention discloses an antibacterial peptide and application thereof in preventing and treating dental plaque and gingival problems, and belongs to the technical field of biology. According to the invention, two cationic antibacterial peptides LR18 and LR18-2 with amphiphilic alpha-helical structures are designed from the beginning. The two antibacterial peptides have good antibacterial and bactericidal activity on oral periodontal pathogenic bacteria (including fusobacterium nucleatum, porphyromonas gingivalis and streptococcus mutans), the minimum inhibitory concentration (MIC) is 62.5-500 [mu] g / mL, and the minimum bactericidal concentration (MBC) is 62.5-2000 [mu] g / mL. The structure is simple, the chemical synthesis difficulty is low, a high-purity product can be directly synthesized, the cell hemolytic activity is low, the safety is high, the product can be used for preparing oral antibacterial drugs and / or oral care products, and oral diseases are prevented and treated by inhibiting the growth of oral periodontal pathogenic bacteria.

Heterocyclic compounds with a novel pyrazole thioamide-based NNSN structural motif, having highly effective zinc- or copper-activated toxicity against microbial infections at micromolar or nanomolar minimum inhibitory concentrations (MIC), and methods of making and using the same.

The invention relates to the technical field of biology, in particular to a pagrosomus major antibacterial peptide Pm-NK-lysin as well as a preparation method and application of the pagrosomus major antibacterial peptide Pm-NK-lysin. The amino acid sequence of the antibacterial peptide is as shown in SEQ ID NO: 1. The minimum inhibitory concentration of the antibacterial peptide to vibrio anguillarum is not higher than 8 [mu] g / ml, and / or the minimum inhibitory concentration of the antibacterial peptide to escherichia coli is not higher than 4 [mu] g / ml. The antibacterial peptide is prepared through a pichia pastoris expression system. The antibacterial peptide is applied to preparation of an antibacterial preparation. According to the invention, efficient secretory expression of recombinant Pm-NK-lysin is successfully realized by creatively utilizing a pichia pastoris eukaryotic expression system, and a protein purification process is optimized, so that sufficient sources of high-activity recombinant protein are guaranteed. The Pm-NK-lysin provided by the invention has an excellent killing effect on aquatic pathogenic bacteria. The antibacterial peptide Pm-NK-lysin is used for replacing or reducing the use of antibiotics to control the harm of aquatic bacterial diseases, has wide popularization and application values, and certainly has far-reaching significance for promoting the green and healthy development of the aquaculture industry.

The application provides a thioglycolic acid modified carbon quantum dot, which is prepared by the following method: (1) preparing a carbon quantum dot solution by using Dicranopteris dichotoma leaves and / or Ricinus communis leaves as raw materials; (2) adding thioglycolic acid into the carbon quantum dot solution obtained in the step (1) so that the concentration of the thioglycolic acid is 0.5mmol-5mmol; after being sufficiently dissolved and mixed, the reaction is carried out at 100-140 DEG C for 1-6 hours to obtain the thioglycolic acid modified carbon quantum dot. The application finds that under suitable conditions, the inhibition effect of the thioglycolic acid modified carbon quantum dot on Ralstonia solanacearum is significantly enhanced, and the minimum inhibitory concentration and the bactericidal concentration are obviously reduced.

The invention relates to a quinoxaline derivative containing trimethyl and n-propyl as well as a preparation method and application of the quinoxaline derivative, and the derivative is 1, 6, 7-trimethyl-3-propyl quinoxaline-2 (1H)-ketone and is particularly suitable for inhibiting fusarium oxysporum. The derivative is prepared by an organic synthesis method which comprises the step of carrying out cyclization reaction on N-protected o-phenylenediamine and a carbonyl compound in the presence of trifluoroacetic acid. Experiments show that the compound has a remarkable antibacterial effect on fusarium oxysporum, and the minimum inhibitory concentration is 0.50 mg / mL. The derivatives can destroy the cell membrane structure of fusarium oxysporum and cause leakage of RNA, protein and reducing sugar in cells, so that the growth of thalli is inhibited. The invention provides a theoretical basis and an experimental basis for developing a novel efficient and low-toxicity bacteriostatic agent.

This invention provides modified antimicrobial peptides, belonging to the field of antimicrobial peptide technology. The modified antimicrobial peptides include at least one of a first, second, third, fourth, fifth, and sixth antimicrobial peptide; the amino acid sequences of the first, second, third, fourth, fifth, and sixth antimicrobial peptides are shown sequentially as SEQ ID NO.1 to SEQ ID NO.6. Based on prevotellin-2, the modified antimicrobial peptides were obtained by reducing negatively charged amino acids, increasing positively charged amino acids, introducing hydrophobic amino acids, adjusting or deleting amino acid sequences, and optimizing the peptide structure. In vitro minimum inhibitory concentration (MIC) determination showed that, compared with the initial peptide, the modified antimicrobial peptides exhibited significantly enhanced antimicrobial activity against bacteria and fungi, and also showed significant bactericidal activity against clinically resistant bacteria.

This invention discloses the application of larvicin or its pharmaceutical salt in the preparation of antifungal drugs. The structure of larvicin is shown below. This invention discovers an effective antifungal compound with pharmaceutical potential: larvicin. The compound larvicin of this invention exhibits clear antifungal activity against pathogenic fungi such as *Candida albicans*, *Candida auris*, *Candida tropicalis*, *Candida parapsilosis*, *Candida krusei*, *Cryptococcus neoformans*, *Trichophyton mentagrophytes*, and *Trichophyton rubrum*, with a minimum inhibitory concentration (MIC). 90 The range is 2–8 μg / mL.

This invention discloses the application of *Polygonum aviculare* extract in the prevention and control of bacterial leaf spot in peach. The invention utilizes ultrasound-assisted extraction to extract the active components of *Polygonum aviculare*. Antibacterial experiments demonstrated that the extract exhibits good antibacterial activity against the pathogen of peach bacterial leaf spot (*Xanthomonas arboricola* pv. pruni, Xap), with a minimum inhibitory concentration (MIC) identical to that of the positive control drug oxytetracycline, both at 0.125 mg / mL. The antibacterial activity of *Polygonum aviculare* extract is comparable to that of oxytetracycline, making it a potential agent for the prevention and control of peach bacterial leaf spot.

The application provides a single bacterium identification method, system, device, medium and drug sensitivity detection method based on lens-free imaging, and belongs to the technical field of biological image processing. The single bacterium identification method based on lens-free imaging comprises steps of gray scale processing, edge detection and single bacterium identification, and further comprises steps of background removal, abnormal pixel correction, signal enhancement and outlier screening. The single bacterium identification method, system, device and medium have the advantages of high speed and high accuracy. Further used for bacterial drug sensitivity detection, the proliferation of bacteria can be obtained in a short time, and then the minimum inhibitory concentration of antibiotics is obtained, which has great application value.

The present invention belongs to the technical field of biopharmaceuticals and specifically relates to use of a pharmaceutical composition in combating mycobacterial infection. The use of zuclopenthixol in combination with bedaquiline exhibits significantly enhanced anti-mycobacterial infection activity. Compared to the use of bedaquiline alone, the use of 2 μg / ml zuclopenthixol in combination with bedaquiline results in varying reductions in colony counts of the MmpL5-MmpS5 strain when the concentration of bedaquiline ranges from 1 / 16 MIC to 2 MIC. As an enhancer of bedaquiline, zuclopenthixol can enhance the anti-mycobacterial infection activity of bedaquiline. The minimum inhibitory concentration of zuclopenthixol against the Rv0678 mutant strain in vitro is 16 μg / ml, and the minimum inhibitory concentration of BDQ against the Rv0678 mutant strain in vitro is 1 μg / mL. The use of 1 μg / ml zuclopenthixol in combination with BDQ reduces the MIC of BDQ against the Rv0678 mutant strain from 1 μg / ml to 0.03 μg / ml (a 32-fold increase in efficacy), which is lower than the MIC against the wild strain H37Rv (0.06 μg / ml), reversing resistance to BDQ and further enhancing the anti-mycobacterial infection activity.

This invention discloses a PKPD-guided method for treating porcine Pasteurella multocida with antibiotics. YDMS injection is used as the antibiotic, administered intramuscularly to pigs infected with Pasteurella multocida. The dosing regimen is adjusted based on in vivo PK / PD target values. The minimum inhibitory concentration (MIC) of YDMS against Pasteurella multocida is 0.06 μg / mL. PK / PD monitoring is performed using a combination of colloidal gold rapid detection and quantitative real-time PCR. This invention clarifies the three-level PK / PD target values ​​of YDMS against Pasteurella multocida and uses AUIC as the core quantitative indicator, avoiding the blindness of traditional empirical dosing. This ensures precise matching of drug concentration and infection severity, effectively reducing the risk of infection aggravation due to insufficient medication or cumulative toxicity caused by overdose, and significantly improving the consistency of treatment efficacy.

The invention belongs to the technical field of prevention and control of drug-resistant bacteria, and particularly discloses a composite bactericidal composition and application thereof in preparation of a reagent for killing aeromonas hydrophila oxytetracycline drug-resistant strains. The minimum inhibitory concentration of the epsilon-polylysine to an aeromonas hydrophila oxytetracycline drug-resistant strain is as low as 3.125 g / mL. Meanwhile, the sterilization mechanism of the epsilon-polylysine on aeromonas hydrophila oxytetracycline drug-resistant strains is discussed through metabonomics research. On the basis, the application finds that various exogenous small molecule metabolites such as 2-phenylacetamide and the like are combined with epsilon-polylysine for use, so that the absorption of drug-resistant bacteria on epsilon-polylysine can be promoted, the sterilization effect of the epsilon-polylysine is effectively enhanced, and the problem of drug resistance of bacteria is solved. Therefore, when the epsilon-polylysine and the exogenous small molecule metabolite are jointly applied, compared with the existing single antibiotic therapy, the epsilon-polylysine has higher activity and better safety and operability in preparation of the reagent for resisting the aeromonas hydrophila oxytetracycline drug-resistant strain.

The invention discloses an antibacterial peptide NyAmp-a and application thereof, and relates to the technical field of biological medicines. The amino acid sequence of the antibacterial peptide is as shown in SEQ ID NO. 1. The invention also provides an application of the antibacterial peptide NyAmp-a in preparation of an antibacterial product for inhibiting staphylococcus aureus, bacillus subtilis, escherichia coli and aeromonas hydrophila, and a minimum inhibitory concentration of the antibacterial peptide NyAmp-a to each bacterium. The invention provides a novel efficient antibacterial solution for four common pathogenic bacteria, namely staphylococcus aureus, bacillus subtilis, escherichia coli and aeromonas hydrophila. The antibacterial peptide NyAmp-a has the characteristic that drug resistance is not easy to generate, a related antibacterial composition can be applied to the fields of medicine, agriculture, food and the like, has important practical application value, and effectively solves the problems that traditional antibiotics are easy to generate drug resistance, and existing antibacterial peptides are high in cytotoxicity and lack of selectivity for specific strains.

A catheter cap (100) includes a housing defining at least one cavity (104) and an opening (106) at a distal end of the housing, and an antimicrobial agent (108) within the at least one cavity. The housing is configured to couple to a catheter luer (22) at the distal end. The at least one cavity is configured to contain a catheter lock solution in contact with the catheter luer at the opening. The antimicrobial agent is present in an amount sufficient to maintain a minimum inhibitory concentration (MIC) of the antimicrobial agent in the catheter lock solution for a period of time between successive operations of the catheter luer.