Compound having broad-spectrum antibacterial activity and antibacterial composition thereof

Abstract

The present invention relates to a compound having broad-spectrum antibacterial activity and an antibacterial composition thereof. The compound having the broad-spectrum antibacterial activity has a general formula as represented by formula (I). The compound provided by the present invention is a novel antibacterial drug-source compound having a broad antibacterial spectrum, good antibacterial activity, suitable in vivo pharmacokinetics, and a remarkable in vivo therapeutic effect. Preferred compound BAB159 has good antibacterial activity on Staphylococcus, Clostridium perfringens, Enterococcus, Bacillus, Streptococcus, Haemophilus, Candida krusei, Aspergillus niger, and Trichophyton, is comparable or superior to drugs on the market, can enrich a molecular library of antibacterial drug sources, alleviates the severe situation of drug resistance, and will provide a new therapeutic choice for infections caused by clinically drug-resistant pathogenic bacteria. Preferred compound BAB159 used in combination with polymyxin E has significantly enhanced synergistic antibacterial activity, particularly antibacterial activity on multidrug-resistant strains.

Description

A compound with broad-spectrum antibacterial activity and antibacterial composition thereof Technical Field

[0001] The present invention belongs to the technical field of antibacterial compounds, and in particular relates to a compound with broad-spectrum antibacterial activity and an antibacterial composition thereof. Background Art

[0002] With the widespread use of antibiotics, drug resistance of pathogens has become more serious, and bacterial infections, especially multidrug-resistant infections, are increasingly facing a situation where no drugs are available. As shown in Example 3 of the present invention, Clostridium perfringens has shown a high resistance rate to many antibiotics, such as lincomycin (76.9%), doxycycline (69.2%), tilmicosin (65.4%), and tiamulin (50.0%), and some MIC values ​​can reach 128 μg / mL or even higher. According to studies, if it is not controlled, the number of deaths caused by drug resistance is expected to reach 10 million by 2050. In order to cope with the serious public health threat brought by bacterial resistance, the World Health Organization (WHO) and the U.S. Food and Drug Administration (FDA) have successively released lists of bacteria that are in urgent need of new antibiotics (WHO, 2017; FDA, 2017), which shows the urgency of developing new antibiotics.

[0003] The development of "super antibiotics" that can combat drug-resistant bacteria has become a rigid demand for medical development. However, due to the limited variety of natural product structures and the increasingly low frequency of discovery, the development of new antibiotics from natural sources has become increasingly difficult. At the same time, because the treatment cycle of antibiotics is shorter than that of drugs for hypertension, diabetes, leukemia, etc., and R&D investment and revenue are relatively low, pharmaceutical companies lack the motivation to develop new antibiotics. In the past 50 years, only daptomycin, a new antibacterial drug from natural sources, has been put into clinical use. Currently, artificially designing and modifying compounds that may have antibacterial potential is an important means of discovering new antibacterial compounds and has received widespread attention in recent years.

[0004] Benzanilide derivatives are a class of widely used compounds. This backbone, based on salicylic acid, is bound to aromatic aniline derivatives via amide bonds, exhibiting diverse biological activities, including herbicidal, insecticidal, antibacterial, and anticancer activities. Previous studies have examined the modification of substituents in benzoylanilide compounds, yielding several compounds with antibacterial activity against Gram-positive bacteria (Bakker et al., J Am Chem Soc, 2023, 145, 1136). Comparison revealed that the compounds reported by Bakker et al. (2023) were mostly heterocyclic structures, and the lowest MIC for MRSA among the 12 compounds reported by Bakker et al. (2023) was 6.25 μg / mL, which is insufficient to meet current practical needs. A search revealed that as of January 2023, there were two patents for applications based on a benzoylanilide core structure. CN1958565A proposes a novel snail-killing drug; CN102697760A proposes the use of niclosamide or its salts in the preparation of a drug for the prevention and treatment of pulmonary fibrosis. However, there are no reports of such compounds as broad-spectrum antibacterial drugs, particularly those for antibacterial purposes, and their compositions.

[0005] Summary of the Invention

[0006] To fill the gap in the antibacterial application of compounds containing benzanilide as the core structure, and to propose a fully synthesized benzanilide compound with independent intellectual property rights for antibacterial applications, the present invention proposes a compound with broad-spectrum antibacterial activity. This compound can be modified with various groups to obtain compounds containing benzanilide as the core structure with varying activity and applications. The most effective compound, BAB159, was screened and identified. The compound provided by the present invention exhibits a broad antibacterial spectrum, good antibacterial activity, suitable in vivo pharmacokinetics, and significant in vivo therapeutic efficacy.

[0007] The present invention also discovered that BAB159 and colistin E have a synergistic effect. When used in appropriate proportions, they exhibit superior antibacterial activity, particularly against multidrug-resistant bacteria. This is of great practical significance and clinical research interest in an environment where various bacteria are increasingly developing resistance to common antibiotics. To address the aforementioned technical issues, the present invention provides the following technical solutions:

[0008] A compound with broad-spectrum antibacterial activity has the general formula (I):

[0009] Among them, R1, R2, R3, R4, and R5 are selected from at least one of H, C1-4 alkyl, C1-4 alkoxy, halogen, hydroxyl, and nitro; the H atoms on the C1-4 alkyl and C1-4 alkoxy groups are optionally substituted by halogen atoms; provided that at least 2 of R1, R2, R3, R4, and R5 are halogen, but not more than 4.

[0010] Preferably, at least one of R1, R2, R3, R4, and R5 is CF3, but no more than two.

[0011] In a preferred technical solution of the present invention, the compound having broad-spectrum antibacterial activity is the following specific compound:

[0012] After extensive screening, the inventors selected the above-mentioned specific compounds as representative benzanilide derivatives with broad-spectrum antibacterial activity of the present invention. Preferably, compound BAB159 exhibits the strongest antibacterial activity and a broad spectrum of antibacterial activity, outperforming most known commercial antibiotics.

[0013] The present invention also provides an antibacterial composition comprising the following active ingredients: the compound represented by the above formula (I) and polymyxin.

[0014] Furthermore, in the antibacterial composition, the concentration ratio of the compound represented by formula (I) to polymyxin is 1-3:1-3. The concentration ratio is a mass concentration ratio. For different bacteria, the mass concentration of the compound represented by formula (I) varies, generally 0.01-16 μg / mL, preferably 0.1-1 μg / mL, such as 0.5 μg / mL.

[0015] Furthermore, the polymyxin is selected from at least one of polymyxin A, polymyxin B, polymyxin C, polymyxin D, and polymyxin E, preferably polymyxin E.

[0016] In a preferred technical solution of the present invention, the active ingredients of the antibacterial composition are BAB159 and polymyxin E.

[0017] More preferably, the concentration ratio of BAB159 to colistin is 1-3:1-3.

[0018] The inventors unexpectedly discovered that the combination of the present compound BAB159 and polymyxins, particularly polymyxin B, exhibits significant synergistic antibacterial activity against multidrug-resistant Escherichia coli B2 (FIC < 0.078), with particular antibacterial activity against multidrug-resistant strains. This strong synergistic effect has not been observed with BAB159 and other antibacterial compounds, such as ciprofloxacin, kanamycin, and polymyxin B.

[0019] The present invention also provides the compound with broad-spectrum antibacterial activity or the use of the antibacterial composition in the preparation of antibacterial drugs.

[0020] Furthermore, the antibacterial drug has an inhibitory / killing effect on fungi and bacteria, and the bacteria include at least one of Staphylococcus, Clostridium perfringens, Enterococcus, Bacillus, Streptococcus, Haemophilus, and Mycobacterium smegmatis; the fungi include at least one of Candida, Aspergillus niger, Aspergillus flavus, and Trichophyton.

[0021] The excellent effects of the present invention are:

[0022] 1. The present invention provides a novel antibacterial drug source compound with a broad antibacterial spectrum, good antibacterial activity, suitable in vivo pharmacokinetics, and significant in vivo therapeutic effect. Among them, the preferred compound BAB159 has a minimum inhibitory concentration (MIC) of 1.1% against Staphylococcus aureus (including MRSA), Clostridium perfringens, Enterococcus, Bacillus, Streptococcus, and Haemophilus influenzae. 50 ) were 0.01 μg / mL, 0.25 μg / mL, 0.25 μg / mL, 0.01 μg / mL, 0.125 μg / mL, and 16 μg / mL, respectively. The MIC values ​​for Candida krusei ATCC 6258, Aspergillus niger, Aspergillus flavus, and Trichophyton were 1 μg / mL, 0.25 μg / mL, 1 μg / mL, and 0.125 μg / mL, respectively. The antibacterial activity of BAB159 provided by the present invention against common clinical pathogens is comparable to or better than that of marketed drugs linezolid, ceftiofur, penicillin, vancomycin, lincomycin, doxycycline, tilmicosin, tylosin, quinocetone, and amphotericin B. The compounds provided by the present invention enrich the molecular library of antibacterial drug sources, alleviate the severe situation of drug resistance, and will provide a new treatment option for infections caused by clinical drug-resistant pathogens. In the current reality that more and more bacteria are becoming resistant to antibiotics, it has extremely important scientific research value and clinical practical significance.

[0023] Second, the present invention also unexpectedly discovered that the combination of BAB159 and colistin exhibits significantly enhanced synergistic antibacterial activity, particularly against multidrug-resistant strains. Therefore, antibacterial compositions containing BAB159 and colistin as active ingredients have the potential to be highly effective. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is a hydrogen nuclear magnetic resonance spectrum of compound BAB159 (solvent DMSO);

[0025] FIG2 is a carbon NMR spectrum of compound BAB159;

[0026] FIG3 is a high-resolution mass spectrum of compound BAB159 in positive ion mode;

[0027] FIG4 is a high-resolution mass spectrum of compound BAB159 in negative ion mode;

[0028] Figure 5 shows the synergistic antibacterial activity of compound BAB159 and polymyxin E against multidrug-resistant E. coli B2;

[0029] FIG6 is a growth curve of Staphylococcus aureus ATCC 29213, MRSA T144, and vancomycin-resistant Enterococcus faecium CAU369 under the action of BAB159;

[0030] FIG7 is a time-kill curve of BAB159 against Staphylococcus aureus ATCC 25923;

[0031] FIG8 shows the protective efficacy of BAB159 against infection with greater wax moth;

[0032] FIG9 shows the survival rate of infected mice under the action of BAB159. DETAILED DESCRIPTION

[0033] To make the purpose, technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be described in detail below. The following examples are convenient for better understanding of the present invention, but are not intended to limit the present invention. The experimental methods in the following examples are all conventional methods unless otherwise specified.

[0034] The standard strains used in this invention, such as Staphylococcus aureus ATCC 29213 and Candida krusei ATCC 6258, were purchased from the National Standard Material Network. Clinical strains A57-1, B58-2, A3-2, B4, and B5 were isolated from animal tissues, excreta, and animal feed. All of these strains were maintained at the National Key Laboratory of Veterinary Public Health Safety as required.

[0035] Preparation Example

[0036] Preparation Example The synthetic strategy for preparing the compound of formula (I) of the present invention is illustrated using compound BAB159 as an example. When preparing other compounds, only the raw materials with different substituents need to be replaced, and the same synthetic strategy as that for preparing BAB159 can be used.

[0037] The synthetic route of compound BAB159 is as follows:

[0038] The specific steps include:

[0039] (S1) Tetrahydrofuran was added to a three-necked flask with stirring to displace nitrogen. The mixture was cooled to -75°C, and 29.8 g of butyl lithium (1 eq) was added dropwise under temperature control. Then, 47.1 g of diisopropylamine (1 eq) was added dropwise under temperature control, and the mixture was stirred for 10 min. Then, 100 g of 1,2-dichloro-3-(trifluoromethyl)benzene (1 eq) was added dropwise. After addition, the mixture was incubated for two hours. The reaction solution was poured into dry ice, naturally warmed to room temperature, and stirred overnight. The reaction solution was concentrated to remove tetrahydrofuran, and 100 mL of water and 200 mL of ethyl acetate were added. The pH was adjusted to 3, and the mixture was separated. The organic phase was concentrated to obtain the crude product, slurried with n-hexane, and filtered to obtain 72 g of the intermediate product Cpd1, with a yield of 60%.

[0040] (S2) 72 g (1 eq) of Cpd1 was added to a single-necked flask and dissolved in 720 mL of dioxane. 350 mL of tert-butyl alcohol, 112 g (4 eq) of triethylamine, and 115 g of diphenylphosphoryl azide (1.5 eq) were then added sequentially. The atmosphere was flushed with nitrogen three times and the reaction was allowed to proceed overnight. The reaction solution was poured into ice and extracted with concentrated ethyl acetate. The organic phase was stirred (petroleum ether:ethyl acetate = 20:1) to obtain 72 g of the intermediate product, Cpd2, in a yield of 78.4%.

[0041] (S3) 72 g of Cpd2 was added to a single-necked flask and dissolved in 720 mL of ethyl acetate. 720 mL of saturated hydrochloric acid and ethyl acetate was then added and stirred overnight. A white solid gradually precipitated, which was the product. The resulting solid was filtered to obtain 57 g of the intermediate product, Cpd3, with a yield of 98%.

[0042] (S4) Dissolve 100 g of salicylic acid in 1 L of dichloromethane, add 8 ml of N,N-dimethylformamide, add 1.2 eq of oxalyl chloride under ice bath conditions, and react at room temperature for 2 hours until the reaction becomes clear. After the control is complete, the acyl chloride compound is dried by spin drying and set aside.

[0043] (S5) 50 g (1 eq) of Cpd3 and acetonitrile were added to a single-necked flask and stirred uniformly. Potassium iodide (62 g (2 eq)) was then added, followed by the slow addition of 43 g (1.2 eq) of the acyl chloride prepared in step (S4) (dissolved in acetonitrile). The reaction was continued at 80°C for 16 h. The mixture was allowed to stand overnight until solid precipitated. After filtration, the filter cake was dissolved in ethyl acetate and washed twice with water. The organic phase was dried and the resulting product was spin-dried to dryness. The product was slurried with dichloromethane and filtered to obtain BAB159 in a yield of 38.4%.

[0044] Figure 1 is a hydrogen nuclear magnetic resonance spectrum (solvent DMSO) of compound BAB159. Figure 2 is a carbon nuclear magnetic resonance spectrum of compound BAB159. Figure 3 is a high-resolution mass spectrum of compound BAB159 in positive ion mode. Figure 4 is a high-resolution mass spectrum of compound BAB159 in negative ion mode. Based on Figures 1 to 4, the structure of compound BAB159 obtained in Example 5 can be determined as follows:

[0045] Example 1 Antibacterial activity of BAB159 against common clinical pathogenic bacteria and fungi

[0046] Accurately weigh the compound BAB159 obtained in the preparation example, dissolve an appropriate amount in dimethyl sulfoxide (DMSO), add 100 μL of MHB broth medium to a 96-well U-shaped plate, take 100 μL of a certain concentration of compound and add it to the first column of the 96-well U-shaped plate, and dilute it to the 10th column in a multiple ratio. Pick a single colony of the test strain in BHI broth and culture it on a shaker at 37°C until the bacterial logarithmic growth phase. Use a McFarland turbidimeter to adjust the bacterial turbidity to a McFarland turbidity of 0.5 and dilute it 100 times (about 10 6 CFU / mL), 100 μL of the above bacterial solution was added to a 96-well U-shaped plate. Columns 11 and 12 contained only MHB broth and the test bacteria, respectively, serving as negative and positive controls. The 96-well U-shaped plate was incubated in a 37°C incubator for 16-18 hours. The experimental results were recorded, and the lowest drug concentration that inhibited bacterial growth was defined as the minimum inhibitory concentration (MIC) of the compound. The results are shown in Tables 1 and 2 below.

[0047] Compound BAB159 was tested against a wider range of bacterial species and strains. The results, shown in Table 1, show that compound BAB159 exhibited strong antibacterial activity against pathogenic bacteria, including Staphylococci (50 strains), Enterococci (27 strains), Bacillus (21 strains), Clostridium perfringens (35 strains), Streptococci (30 strains), and Mycobacterium smegmatis (1 strain). The MICs were 0.01 μg / mL, 0.25 μg / mL, 0.01 μg / mL, 0.25 μg / mL, 0.125 μg / mL, and 2 μg / mL, respectively. BAB159 exhibited comparable or superior antibacterial activity to vancomycin and linezolid.

[0048] Table 1 Antibacterial efficacy of BAB159 against common clinical pathogens (MIC, μg / mL)

[0049] Note: The positive control for enterococci is linezolid, while the positive controls for other strains are vancomycin.

[0050] At the same time, the compound BAB159 also has strong antibacterial activity against common clinical pathogenic fungi such as Candida krusei, Aspergillus flavus, Aspergillus niger, and Trichophyton, with an MIC of 0.5-1 μg / mL. In addition, BAB159 also has certain antibacterial activity against Gram-negative bacteria such as Haemophilus influenzae, with an MIC of 8-32 μg / mL. Based on the above research results, the BAB159 provided by the present invention has better or equivalent antibacterial activity against different genera such as Gram-positive bacteria, some Gram-negative bacteria, and fungi than listed drugs. Its further application will undoubtedly be beneficial to the prevention and control of related clinical diseases.

[0051] Table 2 Inhibitory efficacy of BAB159 against common clinical pathogenic fungi (MIC, μg / mL)

[0052] Example 2

[0053] The antibacterial activity of BAB159, BAB142, BAB151, BAB160, and BAB166 against Clostridium perfringens was tested (n=26). The results are shown in Table 3 below.

[0054] Table 3 Antibacterial activity of compounds with different structures against Clostridium perfringens (MIC 50 , unit μg / mL)

[0055] It can be seen that among the compounds of formula (I), BAB159 has the best antibacterial activity, with MIC 50 The concentration of the active ingredient in the raw material was 0.25 μg / mL. Other similar compounds, such as BAB142, BAB151, BAB160, and BAB166, also have certain antibacterial activity and can meet the antibacterial applications of bacteria / fungi with different drug resistance.

[0056] Example 3 Comparison of antibacterial activity of BAB159 and some marketed antibiotics against Clostridium perfringens

[0057] Clostridium perfringens type A standard strain A57-1 (CVCC 2030), type B standard strain B58-2 (CVCC 60081), type C standard strains C59-1 and C59-2 (CVCC 60101 and CVCC 60102), type D standard strain 60-2D (CVCC 60201), and type E strain E4, purchased from the National Standard Material Network, were removed from a -80°C freezer, thawed at room temperature, and then streaked onto BHA blood agar plates for resuscitation. Twenty-six farm-acquired clinical isolates, including A57-1, B58-2, A3-2, B4, and B5, were removed from a -80°C freezer, thawed at room temperature, and then streaked onto BHA blood agar plates for resuscitation. The isolates were incubated at 37°C under anaerobism for 20–24 hours. Three to five individual colonies were picked with an inoculation loop and inoculated into FTG medium. The culture was then incubated at 37°C under anaerobism for 12 hours. After the culture was completed, the drug sensitivity test was performed, and the bacterial turbidity was adjusted to 0.5 McFarland turbidity using a McFarland turbidimeter and diluted 100 times with FTG medium (the bacterial concentration was about 1×10 6 CFU / mL) for later use. Use FTG culture medium to dilute the drug to be tested into 10 concentration gradients, take 100 μL and add it to a 96-well U-shaped plate, then add 100 μL of the spare bacterial solution to each well, and the 11th and 12th columns are used as negative controls containing only FTG culture medium and positive controls containing only bacterial solution, respectively. The 96-well plate with the completed bacterial solution inoculation is placed at 37°C for anaerobic culture for 12 to 16 hours, and the drug sensitivity results are read. In this experiment, Bacteroides fragilis (ATCC 25285) is used as a quality control bacterium. The results are shown in Table 4 below. Most of the antibiotics tested have a high MIC against Clostridium perfringens, and the MIC of lincomycin against Clostridium perfringens is 50 8 μg / mL, MIC 90 Greater than 128 μg / mL; MIC of doxycycline 50 8 μg / mL, MIC 90 The MIC of tilmicosin is 16 μg / mL. 50 128 μg / mL, MIC 90 Greater than 128 μg / mL; MIC of tiamulin 50 0.5 μg / mL, MIC 90 The compound BAB159 provided by the present invention has excellent antibacterial effect on Clostridium perfringens, and its MIC 50 and MIC 90 The MIC values ​​of BAB159 against 26 strains of Clostridium perfringens tested were 0.25 μg / mL and 0.5 μg / mL, respectively. Compared to commonly used antibiotics in clinical practice, the highest MIC value of BAB159 against the 26 tested strains of Clostridium perfringens was only 0.5 μg / mL, which is comparable to the antibacterial activity of ceftiofur, penicillin, and vancomycin. This indicates that the compound is as effective as or even superior to commonly used antibiotics on the market and has promising application prospects in the treatment of drug-resistant anaerobic Clostridium infections.

[0058] Table 4 Activity of BAB159 and Some Marketed Antibiotics against Clostridium perfringens

[0059] Note: CEF: Cefotaxime, PEN: Penicillin, VAN: Vancomycin, LIN: Lincomycin, DOX: Doxycycline, TMS: Tilmicosin, TIA: Tiamulin, QCT: Quinocetone.

[0060] Example 4 Synergistic Antibacterial Efficacy of BAB159 and Polymyxin E

[0061] The checkerboard broth dilution method was used to determine the synergistic efficacy (FIC) of the combination of BAB159 and polymyxin E against multidrug-resistant Escherichia coli E. coli B2 (NDM-5 + MCR-1). A single colony of E. coli B2 was picked and cultured in BHI broth at 37 °C in a shaker until the logarithmic growth phase. The turbidity of the bacteria was adjusted to a McFarland turbidity of 0.5 using a McFarland turbidimeter and diluted 100-fold (~1.0×10 6 CFU / mL) with MHB medium for later use. 100 μL of polymyxin E at a concentration of 32 μg / mL was added to each well in the first column. Using a multichannel pipette, 100 μL of the solution was serially diluted 2-fold from the first column to the seventh column, and the excess liquid was discarded; 100 μL of BAB159 at a concentration of 2 μg / mL was added to each well in the eighth row. Using a multichannel pipette, 100 μL of the solution was serially diluted 2-fold from the eighth row to the second row, and the excess liquid was discarded. Subsequently, 100 μL of the diluted test bacterial solution was added to each well from the first column to the eighth column. The eleventh and twelfth columns were the negative and positive controls containing only MHB medium and the test bacterial solution, respectively. The results are shown in Figure 5. [[ID=十六]] [[ID=十七]]

[0062] [[ID=十八]]Result interpretation: After incubation at 37 °C for 16 - 十八 h, the FIC value was read. Among them, FIC = MIC (polymyxin E in combination) / MIC (polymyxin E alone) + MIC (BAB159 in combination) / MIC (BAB159 alone). Among them, FIC > 2 indicates antagonism, 1 < FIC ≤ 2 indicates no relevance, 0.5 < FIC ≤ 1 indicates additive effect, and FIC ≤ 0.5 indicates synergistic effect. [[ID=十九]] [[ID=二十]]

[0063] Results showed that when used alone, polymyxin E and BAB159 had MICs of 8 μg / mL and >32 μg / mL against multidrug-resistant E. coli B2, respectively. When used in combination, polymyxin E and BAB159 exhibited significant synergy at a concentration ratio of 1-3:1-3. The optimal synergy was achieved when polymyxin E and BAB159 were used in a 1:1 ratio, with both polymyxin E and BAB159 achieving MICs of 0.5 μg / mL against E. coli B2. At this ratio, BAB159 increased the MIC of polymyxin E by 16-fold, with an FIC index of less than 0.078. BAB159 also exhibited synergy when used in combination with polymyxin B (FIC = 0.5), but the effect was not as strong as that of polymyxin E. No synergy was observed when used in combination with ciprofloxacin or kanamycin (FIC = 2).

[0064] The results demonstrate that BAB159, provided by the present invention, can be used in combination with polymyxin E to exert a synergistic antibacterial effect against multidrug-resistant E. coli B2. These results demonstrate that BAB159 not only possesses superior antibacterial activity on its own but can also be used in combination with polymyxin E to enhance its activity against pathogens, particularly multidrug-resistant bacteria. The present invention's BAB159 has promising clinical application prospects.

[0065] Table 5 The synergistic effect of BAB159 on polymyxin E (MIC in μg / mL)

[0066] Example 5 Growth curves of common pathogens under the action of BAB159

[0067] Strains of Staphylococcus aureus ATCC 25923, MRSA T144, and vancomycin-resistant Enterococcus faecium CAU369 were selected and monocloned into BHI broth medium. The culture was shaken at 37°C and 200 rpm until the logarithmic growth phase. The bacterial turbidity was adjusted to a McFarland turbidity of 0.5 using a McFarland turbidimeter and diluted 100-fold (~1.0 × 10 6CFU / mL) and then standby. BAB159 was diluted to the required concentration with MH broth culture medium, 100 μL was taken and added to a 96-well flat-bottom plate, and 100 μL of diluted bacterial solution to be tested was added to each well. Negative and positive controls containing only MH broth culture medium and bacterial solution to be tested were set. The microplate reader system temperature was set to 37 ° C, and the absorbance at OD 600nm was detected. The detection was performed once every hour for a total of 24 hours. Three biological replicates were set for each treatment, and the results are shown in Figure 6. In Figure 6, PBS is the buffer group, 159 is the compound BAB159 group, and van is the vancomycin group. The dynamic curve of bacterial growth can be more intuitively observed that compound BAB159 can significantly inhibit the growth of Staphylococcus aureus ATCC 25923, MRSA and vancomycin-resistant Enterococcus faecium CAU369 at its MIC concentration, wherein the growth inhibition effect on vancomycin-resistant Enterococcus faecium CAU369 is comparable to that of vancomycin.

[0068] Example 6 BAB159 sterilization curve

[0069] A single colony of Staphylococcus aureus ATCC 25923 was picked and placed in 1 mL of BHI broth medium. The bacteria were cultured at 37°C and 200 rpm until the logarithmic growth phase was reached. Subsequently, the concentration of Staphylococcus aureus ATCC 25923 was adjusted to a McFarland turbidity of 0.5 and diluted 100-fold into 5 mL of prepared MH broth to obtain a bacterial concentration of approximately 10 6 CFU / mL of bacterial liquid. Different concentrations of 159 (4×MIC, 10×MIC and 25×MIC) were added to the infected broth, and 10×MIC of vancomycin (Van) and PBS buffer (0×MIC) were added to the infected broth as positive and negative control groups, respectively. Three replicates were set for each treatment and cultured in a shaker at 37°C and 200rpm. 100μL of culture medium was taken out at specific time points after adding the antibacterial compound, diluted in PBS in multiple ratios, plated and counted, and the number of colonies was calculated after inverted culture at 37°C for 24h. The results are shown in Figure 7. As the concentration of BAB159 increased, its antibacterial efficacy did not increase significantly, but as time went on, the antibacterial effect at each concentration became more significant. It proves that BAB159 is a time-dependent bactericidal agent. For time-dependent antibiotics, the pharmacokinetic / pharmacodynamic (PK / PD) parameter that should be selected when formulating the dose is the ratio of the area under the drug-time curve (AUC) to the MIC. Therefore, the ratio of AUC to MIC was selected when subsequently formulating the dosage of BAB159.

[0070] Example 7 Pharmacokinetic Characteristics of BAB159

[0071] To investigate the metabolic residues of BAB159 in animal models, rabbits were used as an animal model to quantitatively analyze BAB159 levels in rabbit plasma. Male Chinese white rabbits weighing approximately 2 kg were used. After one week of adaptive feeding, 2 mL of a BAB159 suspension at a dose of 20 mg / kg bw was injected intramuscularly into the left thigh. Blood was collected from the ear vein at eight time points: 0.5, 1, 2, 4, 6, 8, 12, and 24 hours after administration. Plasma samples were pre-treated and analyzed by UPLC-MS / MS.

[0072] The results showed that after intramuscular injection, the plasma C max 、T max The MIC of BAB159 against Staphylococcus spp. was obtained from the antibacterial spectrum of BAB159. 50 The pharmacokinetic parameters showed that the area under the drug-time curve (AUC) after intramuscular injection was 1708 μg / L·h, and the AUIC was 109. Studies have shown that when the AUIC of a time-dependent antibiotic is greater than 100, the compound is considered to have a superior therapeutic effect (Pharmaceutics, 2021, 13(5): 602). The above results indicate that the compound BAB159 of the present invention has great application potential in the treatment of clinically relevant pathogenic infections.

[0073] Table 6 Pharmacokinetic parameters of BAB159 in rabbits

[0074] Note: T max : peak time; C max : maximum plasma concentration; Vd: apparent volume of distribution; AUC: area under the concentration-time curve; T 1 / 2 : half-life; CL: elimination constant.

[0075] Example 8 Efficacy of Compound BAB159 in Animal Infection Models

[0076] In vivo infection model of G. mellonella: 300 mg G. mellonella larvae were randomly divided into 8 groups. Each G. mellonella was injected with 10 μL of MRSA T144 suspension (final concentration 5.5×10 6CFU / mouse). One hour after bacterial infection, the right ventral pedicles of the Greater Glyptospira moth were injected with 10 μL of BAB159 solution at a dose of 2 mg / kg bw. The positive control was vancomycin at the same concentration of 2 mg / kg bw. The survival rate of the Glyptospira moths in each group was recorded daily for 5 days. Figure 8 shows the protective efficacy of the compound BAB159 against Glyptospira moth infection. In this Glyptospira moth infection model, BAB159 demonstrated a 70% protective rate against Glyptospira moths within 5 days of infection, surpassing the 40% protection achieved by vancomycin.

[0077] Mouse bacteremia model: C57BL / 6J female mice weighing between 18-20g were used. After one week of adaptive feeding, the mice were randomly divided into 5 groups, with 7 mice in each group. Each mouse was intraperitoneally injected with 200μL of MRSA T144 bacterial suspension (final concentration of 1.5×108CFU / mouse). One hour after bacterial infection, the mice were given the corresponding compounds and the positive control vancomycin at a dose of 10mg / kg bw. The survival rate of mice was recorded within 72 hours. Figure 9 shows the survival rate of infected mice under the action of BAB159. In the mouse infection model, the protection rate of BAB159 against mice was 100% within 3 days, which is comparable to the efficacy of vancomycin, and the efficacy is significantly stronger than that of the PBS group.

[0078] These results demonstrate that BAB159, developed by the present invention, exhibits excellent antibacterial activity against common clinical pathogens and fungi, outperforming some marketed antibiotics. Furthermore, BAB159 exhibits favorable pharmacokinetic parameters and demonstrates promising therapeutic effects in both the greater wax moth and rabbit infection models, suggesting that BAB159 could be used to treat infections caused by these pathogens and holds promising clinical promise.

Claims

1. A compound having broad-spectrum antibacterial activity, characterized in that: The structure of the compound BAB159 is shown below:

2. An antibacterial composition, characterized in that The invention comprises the following active ingredients: the compound with broad-spectrum antibacterial activity as claimed in claim 1, and polymyxin.

3. The antibacterial composition according to claim 2, characterized in that In the antibacterial composition, the concentration ratio of the compound with broad-spectrum antibacterial activity according to claim 1 to polymyxin is 1-3:1-3.

4. The antibacterial composition according to claim 2, characterized in that The polymyxin is selected from at least one of polymyxin A, polymyxin B, polymyxin C, polymyxin D and polymyxin E.

5. The antibacterial composition according to claim 2, characterized in that: The active ingredients of the antibacterial composition are BAB159 and polymyxin E; The concentration ratio of BAB159 and colistin was 1-3:1-3.

6. Use of the compound having broad-spectrum antibacterial activity according to claim 1 or the antibacterial composition according to any one of claims 2 to 5 in the preparation of antibacterial drugs.

7. The use according to claim 6, wherein the antibacterial drug has an inhibitory / killing effect on fungi and bacteria, wherein the bacteria include at least one of Staphylococcus aureus, Clostridium perfringens, Enterococcus, Bacillus, Streptococcus, Haemophilus, and Mycobacterium smegmatis; and the fungi include at least one of Candida albicans, Aspergillus niger, Aspergillus flavus, and Trichophyton.

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