COMPOUND WITH BROAD-SPECTRUM ANTIBACTERIAL ACTIVITY AND ITS ANTIBACTERIAL COMPOSITION

Abstract

A compound with broad-spectrum antibacterial activity and its antibacterial composition are provided. The compound with broad-spectrum antibacterial activity has formula (I), which are antibacterial drug source compounds with a broad antibacterial spectrum, good antibacterial activity, suitable in vivo pharmacokinetics, and significant in vivo therapeutic effects. Preferred compound BAB159 has good antibacterial activity against Staphylococcus, Clostridium perfringens, Enterococcus, Bacillus, Streptococcus, Haemophilus, Candida krusei, Aspergillus niger, and Trichophyton, which is comparable or better than the listed drugs. The combination of preferred compound BAB159 and polymyxin E exhibits significantly enhanced synergistic antibacterial activity, especially against multidrug-resistant strains.

Claims

1. A compound with broad-spectrum antibacterial activity, having a structure as shown in the following compound BAB159: ##STR00005##

2. An antibacterial composition, comprising the following active ingredients: the compound with broad-spectrum antibacterial activity according to claim 1, and polymyxin.

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

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

5-7. (canceled)

8. An antibacterial drug, comprising the compound with broad-spectrum antibacterial activity according to claim 1, wherein the antibacterial drug has inhibitory/bactericidal effects on fungi and bacteria, the bacteria is selected from at least one of Staphylococcus, Clostridium perfringens, Enterococcus, Bacillus, Streptococcus, Haemophilus, and Mycobacterium smegmatis, and the fungi is selected from at least one of Candida, Aspergillus niger, Aspergillus flavus, and Trichophyton.

9. An antibacterial drug, comprising the composition according to claim 2, wherein the antibacterial drug has inhibitory/bactericidal effects on fungi and bacteria, wherein the bacteria is selected from at least one of Staphylococcus, Clostridium perfringens, Enterococcus, Bacillus, Streptococcus, Haemophilus, and Mycobacterium smegmatis, and the fungi is selected from at least one of Candida, Aspergillus niger, Aspergillus flavus, and Trichophyton.

10. An antibacterial drug, comprising the composition according to claim 3, wherein the antibacterial drug has inhibitory/bactericidal effects on fungi and bacteria, wherein the bacteria is selected from at least one of Staphylococcus, Clostridium perfringens, Enterococcus, Bacillus, Streptococcus, Haemophilus, and Mycobacterium smegmatis, and the fungi is selected from at least one of Candida, Aspergillus niger, Aspergillus flavus, and Trichophyton.

11. An antibacterial drug, comprising the composition according to claim 4, wherein the antibacterial drug has inhibitory/bactericidal effects on fungi and bacteria, wherein the bacteria is selected from at least one of Staphylococcus, Clostridium perfringens, Enterococcus, Bacillus, Streptococcus, Haemophilus, and Mycobacterium smegmatis, and the fungi is selected from at least one of Candida, Aspergillus niger, Aspergillus flavus, and Trichophyton.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0023] FIG. 1 shows the 1H NMR of compound BAB159 in DMSO solvent;

[0024] FIG. 2 shows the 13C NMR of compound BAB159;

[0025] FIG. 3 shows the high-resolution mass spectrum of compound BAB159 in positive ion mode;

[0026] FIG. 4 shows the high-resolution mass spectrum of compound BAB159 in negative ion mode;

[0027] FIG. 5 shows the synergistic antibacterial activity of compound BAB159 in combination with polymyxin E on multidrug-resistant bacteria E. coli B2;

[0028] FIG. 6 shows the growth curves of Staphylococcus aureus ATCC 29213, MRSA T144, and vancomycin resistant Enterococcus faecium CAU369 under the action of BAB159;

[0029] FIG. 7 shows the time-Kill curve of BAB159 against Staphylococcus aureus ATCC 25923;

[0030] FIG. 8 shows the protective efficacy of BAB159 against infection by the Galleria mellonella;

[0031] FIG. 9 shows the survival rate of infected mice under the action of BAB159.

DETAILED DESCRIPTION OF THE INVENTION

[0032] In order to clarify the purpose, technical solution, and advantages of the present invention, a detailed description of the technical solution of the present invention will be provided below. The following embodiments facilitate a better understanding of the present invention, but do not limit the present invention. The experimental methods in the following embodiments, unless otherwise specified, are all conventional methods.

[0033] The standard strains used in the present invention, such as Staphylococcus aureus ATCC 29213 and Candida krusei ATCC 6258, were purchased from the National Standard Material Network. Clinical strains, such as A57-1, B58-2, A3-2, B4 and B5, were isolated from animal tissues, excreta, and feeding environments. The above strains are stored in the National Key Laboratory of Veterinary Public Health and Safety as required.

Preparation Example

[0034] Taking compound BAB159 as an example, the synthesis strategy for preparing compound (I) of the present invention is illustrated. When preparing other compounds, it is only necessary to replace the raw materials with different substituents to obtain the other compounds through the same synthesis strategy for preparing BAB159.

[0035] The synthesis route of compound BAB159 is as follows:

##STR00003##

[0036] Specifically, it includes the following steps: [0037] (S1) Add tetrahydrofuran to a there-necked flask and stir to replace nitrogen. Cool down to 75 C. Add 29.8 g butyl lithium (1 eq) and 47.1 g diisopropylamine (1 eq) dropwise at controlled temperature and stir for 10 minutes. Then add 100 g of 1,2-dichloro-3-(trifluoromethyl)benzene (1 eq) dropwise and incubate for two hours after the addition. The reaction solution was poured into dry ice, naturally heated 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 acid was adjusted to pH 3, and the liquid was separated. The organic phase was concentrated to obtain the crude product, which was then slurried with n-hexane and filtered to obtain 72 g of intermediate product Cpd1 with a yield of 60%. [0038] (S2) Add 72 g (1 eq) of Cpd1 and 720 mL of dioxane to a single-necked flask to dissolve evenly. Then, add 350 mL of tert-butanol, 112 g (4 eq) of triethylamine, and 115 g of diphenylphosphoryl azide (1.5 eq) in sequence. After nitrogen replacement three times, react overnight. Pour the reaction solution into ice, concentrate with ethyl acetate for extraction, and stir the organic phase (petroleum ether:ethyl acetate=20:1) to obtain 72 g of intermediate product Cpd2 with a yield of 78.4%. [0039] (S3) Add 72 g of Cpd2 to a single-necked flask, dissolve in 720 mL of ethyl acetate, and then add 720 mL of saturated hydrochloric acid ethyl acetate and stir overnight. The white solid that gradually precipitates is the product. The solid obtained by filtration is 57 g of intermediate product Cpd3 with a yield of 98%. [0040] (S4) Dissolve 100 g of salicylic acid in 1 L of dichloromethane, add 8 mL of N, N-dimethylformamide, and add 1.2 eq of oxalyl chloride under ice bath conditions. React at room temperature for 2 hours until the reaction becomes clarified. After the central control is completed, spin-dry to obtain the acyl chloride compound, which is ready for use. [0041] (S5) Add 50 g (1 eq) of Cpd3 and acetonitrile to a single-necked flask and stir evenly, add potassium iodide (62 g (2 eq)), and slowly add 43 g (dissolved in acetonitrile) of the acyl chloride compound (1.2 eq) prepared in step (S4), and react at 80 C. for 16 hours. Let it stand overnight until a solid precipitate is formed. After filtration, dissolve the filter cake in ethyl acetate and wash it twice with water. Dry the organic phase and spin-dry the resulting product, which was then slurried with dichloromethane and filter the solid to obtain product BAB159 with a yield of 38.4%.

[0042] FIG. 1 shows the 1H NMR of compound BAB159 in DMSO solvent. FIG. 2 shows the 13C NMR of compound BAB159. FIG. 3 shows the high-resolution mass spectrum of compound BAB159 in positive ion mode. FIG. 4 shows the high-resolution mass spectrum of compound BAB159 in negative ion mode. From FIG. 1 to FIG. 4, it can be determined that the structure of compound BAB159 obtained in S5 is as follows:

##STR00004##

Embodiment 1 Antibacterial Activity of BAB159 Against Common Clinical Pathogenic Bacteria and Fungi

[0043] Accurately weigh the compound BAB159 prepared in the preparation example, dissolve it appropriately in dimethyl sulfoxide (DMSO), add 100 L of MHB broth culture medium to a 96 well U-shaped plate, take 100 L of a certain concentration of the compound and add it to the first column of the 96-well U-shaped plate, and dilute it to the 10th column by multiple ratio. Select single colonies of the test strain and culture them in BHI broth on a shaker at 37 C. until the bacterial logarithmic growth stage. Adjust the bacterial turbidity to 0.5 McF using a Maxwell turbidimeter and dilute 100-fold (approximately 10.sup.6 CFU/mL) with MHB broth culture medium. Take 100 L of the above bacterial solution and add it to a 96 well U-shaped plate. The 11th and 12th columns only contain MHB broth culture medium and the test bacterial solution, respectively, as negative and positive controls. Place the 96-well U-shaped plate in a 37 C. constant temperature incubator for 16-18 hours, read the experimental results, and determine the minimum inhibitory concentration (MIC) of the compound as the visible lowest drug concentration that inhibits bacterial growth. The results are shown in Tables 1 and 2 below.

[0044] The number of more types of bacteria and strains were determined by compound BAB159, the results are shown in Table 1. Compound BAB159 has good antibacterial activity against pathogenic bacteria including Staphylococcus (50 strains), Enterococcus (27 strains), Bacillus (21 strains), Clostridium perfringens (35 strains), Streptococcus (30 strains), and Mycobacterium smegmatis (1 strain), with MIC values of 0.01 g/mL, 0.25 g/mL, 0.01 g/mL, 0.25 g/mL, 0.125 g/mL, and 2 g/mL, respectively. BAB159 has better or equivalent antibacterial activity than vancomycin and linezolid.

TABLE-US-00001 TABLE 1 Antibacterial efficacy of BAB159 against common clinical pathogenic bacteria (MICs, unit: g/mL) Clostridium Mycobacterium Staphylococcus Enterococcus Bacillus perfringens Streptococcus smegmatis Project (n = 50) (n = 27) (n = 21) (n = 35) (n = 30) (n = 1) BAB159 0.01 0.25 0.01 0.25 0.125 2 Positive 1 1 0.5 0.5 0.25 16 control

[0045] Note: Except the positive control for Enterococcus, which is linezolid, the positive control for all other strains is vancomycin.

[0046] Meanwhile, compound BAB159 also exhibits strong antibacterial activity against common clinical pathogenic fungi such as Candida albicans, Aspergillus flavus, Aspergillus niger, and Trichophyton, with a MIC of 0.5-1 g/mL. In addition, BAB159 also has certain antibacterial activity against gram-negative bacteria such as Haemophilus, with a MIC of 8-32 g/mL. Based on the above research results, BAB159 provided by the present invention has better or equivalent antibacterial activity against different bacterial genera such as Gram-positive bacteria, some Gram-negative bacteria, and fungi than listed drugs. Its further application will undoubtedly be beneficial for the prevention and control of related diseases in clinical practice.

TABLE-US-00002 TABLE 2 Antibacterial efficacy of BAB159 against common clinical pathogenic fungi (MICs, unit: g/mL) MICs (g/mL) Strains BAB159 Amphotericin B Candida albicans ATCC 6258 1 0.5 Aspergillus flavus ATCC 11492 1 0.25 Aspergillus niger ATCC 96918 0.5 0.125 Trichophyton ATCC MTA-4439 0.125 0.25

Embodiment 2

[0047] 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.

TABLE-US-00003 TABLE 3 Antibacterial activity of compounds with different structures against Clostridium perfringens (MIC.sub.50, unit: g/mL) BAB159 BAB142 BAB151 BAB160 BAB166 0.25 16 8 8 32

[0048] It can be seen that among the compounds of formula (I), BAB159 has the best antibacterial activity with a MIC.sub.50 of 0.25 g/mL. Other similar compounds, such as BAB142, BAB151, BAB160, and BAB 166, also have certain antibacterial activity and can meet the antibacterial applications of different drug-resistant bacteria/fungi.

Embodiment 3 Comparison of Antibacterial Activity of BAB159 and Some Listed Antibiotics Against Clostridium perfringens

[0049] Take out the A-type standard strain A57-1 (CVCC 2030), B-type standard strain B58-2 (CVCC 60081), C-type standard strains C59-1 and C59-2 (CVCC 60101, CVCC 60102), D-type standard strain 60-2D (CVCC 60201), and E-type strain E4 of Clostridium perfringens purchased from the National Standard Material Network in an 80 C. freezer, thaw at room temperature, and apply them to BHA blood plates for streaking and recovery. Take out 26 clinical isolates from farms, such as A57-1, B58-2, A3-2, B4 and B5, in a 80 C. freezer, thaw at room temperature, and apply them to BHA blood plates for streaking and recovery. Culture at 37 C. in anaerobic environment for 20-24 hours, pick 3-5 single colonies with an inoculation ring, inoculate them in FTG culture medium, and let them stand at 37 C. in anaerobic environment for 12 hours. After the culture was completed, a drug sensitivity test was carried out. Adjust bacterial turbidity to 0.5 McF using a Maxwell turbidimeter and dilute 100-fold with FTG culture medium (at this time, the bacterial concentration is about 110.sup.6 CFU/mL) for later use. Dilute the test drug to 10 concentration gradients using FTG culture medium, take 100 L and add it to a 96 well U-shaped plate. Then add 100 L of spare bacterial solution to each well, and the 11th and 12th columns are used as negative controls containing FTG culture medium only and positive controls containing bacterial solution only, respectively. Place the 96-well U-shaped plate that has completed bacterial solution inoculation in anaerobic culture at 37 C. for 12-16 hours and read the drug sensitivity results. In this experiment, Bacteroides fragilis (ATCC 25285) was used as the quality control bacterium. As shown in Table 4, most of the tested antibiotics have high MICs against Clostridium perfringens. The MIC.sub.50 of lincomycin against Clostridium perfringens is 8 g/mL, and the MIC.sub.90 is greater than 128 g/mL. The MIC.sub.50 and MIC.sub.90 of doxycycline are 8 g/mL and 16 g/mL, respectively. The MIC.sub.50 and MIC.sub.90 of tilmicosin are 128 g/mL and greater than 128 g/mL, respectively. The MIC.sub.50 and MIC.sub.90 of tiamulin is 0.5 g/mL and 8 g/mL, respectively. The compound BAB159 provided by the present invention has excellent antibacterial effect on Clostridium perfringens, with MIC.sub.50 and MIC.sub.90 of 0.25 g/mL and 0.5 g/mL, respectively. Compared with commonly used antibiotics in clinical practice, BAB 159 has the highest MIC value of only 0.5 g/mL against 26 tested strains of Clostridium perfringens, which was comparable to the antibacterial activity of ceftiofur, penicillin, and vancomycin. This indicates that the compound has comparable or even better efficacy compared to listed commonly used antibiotics and has good application prospects in the treatment of drug-resistant anaerobic Clostridium infections.

TABLE-US-00004 TABLE 4 Activity of BAB159 and some listed antibiotics against Clostridium perfringens Strain MIC value against Clostridium perfringens (g/mL) Type number BAB159 CEF PEN VAN LIN DOX TMS TIA QCT A-type A57-1 0.25 0.25 0.25 0.25 2 0.25 4 4 0.25 A3-1 0.5 0.25 0.25 0.25 1 8 4 0.5 0.5 A3-2 0.25 0.25 0.5 0.25 0.5 8 2 0.5 0.25 B-type B4 0.5 0.25 0.5 0.25 >128 2 >128 4 0.25 B5 0.25 0.25 0.5 0.25 >128 8 >128 0.5 0.25 C-type C3 0.5 1 2 0.5 >128 16 >128 8 1 C8 0.25 0.25 0.25 0.25 128 0.25 >128 0.5 0.25 C59-1 0.25 0.25 0.125 0.25 0.5 0.25 2 0.25 0.25 D-type D14B 0.25 0.25 0.5 0.25 64 1 128 8 0.25 F-type F5-2 0.25 0.25 0.125 0.25 128 4 128 0.5 0.5 F6-1 0.25 0.25 0.25 0.5 32 32 128 0.5 4 F6-2 0.5 0.25 0.125 0.25 32 16 128 0.5 0.5 F6-2-1 0.5 0.25 0.25 0.25 128 16 >128 0.5 1 F6-2-2 0.25 0.25 0.25 0.25 128 16 128 0.5 0.25 F7-1 0.5 0.25 0.5 0.5 >128 8 64 4 0.25 F8-1 0.5 0.25 0.25 0.5 >128 16 128 4 0.5 H-type H12-1 0.25 0.25 0.25 0.25 0.5 4 4 0.5 0.25 H12-2 0.25 0.25 0.125 0.25 0.25 4 4 0.25 0.25 H13-1 0.5 0.25 0.0625 0.25 4 8 4 4 0.25 H14-1 0.5 0.25 0.25 0.5 8 8 128 8 0.25 H14-2 0.5 0.25 1 0.25 8 8 128 8 0.5 H14-4 0.5 0.25 0.125 0.25 4 4 128 4 0.25 H15-1 0.25 0.25 0.25 0.5 0.25 16 4 0.25 0.25 H15-2 0.5 0.25 0.25 0.25 4 16 128 4 0.25 H15-3 0.25 0.25 0.25 0.25 4 8 4 4 0.5 H16 0.25 0.25 0.125 0.5 4 8 128 4 0.25 Note: CEF: Ceftiofur, PEN: Penicillin, VAN: Vancomycin, LIN: Lincomycin, DOX: Doxycycline, TMS: Tilmicosin, TIA: Tiamulin, QCT: Quincetone.

Embodiment 4 Synergistic Antibacterial Efficacy of BAB159 and Polymyxin E

[0050] Using the chessboard broth dilution method for the combined treatment of BAB159 and polymyxin E against multidrug-resistant E. coli B2.sub.(NDM-5+MCR-1) was tested for synergistic efficacy (FIC). E. coli B2 single colony was picked and cultured in BHI broth on a shaker at 37 C. until logarithmic growth stage. Adjust the bacterial turbidity to 0.5 McF using a Maxwell turbidimeter and dilute 100-fold (1.010.sup.6 CFU/mL) with MHB culture medium for future use. Add 100 L of polymyxin E with a concentration of 32 g/mL to each well in the first column. Use a pipette to take 100 L of the solution in sequence and dilute it 2-fold from the 1st column to the 7th column. Discard the excess liquid. Add 100 L of BAB159 with a concentration of 2 g/mL to each well in the 8th row. Use a pipette to take 100 L of the solution and dilute it 2-fold from the 8th row to the 2nd row. Discard excess liquid. Subsequently, add 100 L of diluted tested bacterial solution to each well from 1st column to 8th column. 11th column and 12th column represent negative and positive controls containing only MHB culture medium and only tested bacterial solution, respectively. The result is shown in FIG. 5.

[0051] Result interpretation: after incubation at 37 C. for 16-18 hours, read the FIC value, where FIC=MIC (polymyxin E when combined)/MIC (polymyxin E when used alone)+MIC (BAB159 when combined)/MIC (BAB159 when used alone). Where FIC>2 indicates antagonistic effect, 1<FIC2 indicates irrelevant effect, 0.5<FIC1 indicates additive effect, and FIC<0.5 indicates synergistic effect.

[0052] The results shows that when polymyxin E and BAB159 are used alone, MICs of polymyxin E and BAB159 against multidrug-resistant E. coli B2 are 8 g/mL and >32 g/mL, respectively. When used in combination, polymyxin E and BAB 159 have a significant synergistic effect at a concentration ratio of 1-3:1-3. The best synergistic effect is achieved when polymyxin E and BAB159 are used in a 1:1 concentration ratio. At this time, MICs of polymyxin E and BAB159 against E. coli B2 are both 0.5 g/mL. At this ratio, BAB159 increases the MIC of polymyxin E by 16-fold and the FIC index is less than 0.078. BAB159 also shows a synergistic effect when combined with polymyxin B (FIC=0.5), but the effect is not as strong as polymyxin E, and no synergistic effect was observed when combined with ciprofloxacin and kanamycin (FIC=2).

[0053] This demonstrates that BAB159 provided by the present invention can be used in combination with polymyxin E to treat multidrug-resistant E. coli B2 exerts a synergistic antibacterial effect. The above results indicate that BAB159 not only has superior antibacterial activity on its own, but also can be combined with polymyxin to enhance its activity against pathogenic bacteria, especially multidrug-resistant bacteria. BAB159 provided by the present invention has good clinical application prospects.

TABLE-US-00005 TABLE 5 Synergistic effect of BAB159 against polymyxin E (MICs unit: g/mL) MICs MICs MICs (drug A MICs (drug A (BAB159 (BAB159 when used when used in when used when used in Synergistic Drug A alone) combination) alone) combination) index (FIC) Polymyxin E 8 g/mL 0.5 g/mL >32 g/mL 0.5 g/mL <0.078 Polymyxin B 8 g/mL 2 g/mL >32 g/mL 8 g/mL 0.5 Polymyxin C 16 g/mL 4 g/mL >32 g/mL 16 g/mL 0.75 Ciprofloxacin 32 g/mL 32 g/mL >32 g/mL >32 g/mL 2.0 Kanamycin 128 g/mL 128 g/mL >32 g/mL >32 g/mL 2.0

Embodiment 5 Growth Curves of Common Pathogenic Bacteria Under the Action of BAB159

[0054] Select strains of Staphylococcus aureus ATCC 25923, MRSA T144, and vancomycin resistant Enterococcus faecium CAU369 for monoclonal transfer to BHI broth culture medium, and culture on a shaker at 37 C. and 200 rpm until logarithmic growth stage. Adjust the bacterial turbidity to 0.5 McF using a Maxwell turbidimeter and dilute 100-fold (1.010.sup.6 CFU/mL) with MH broth culture medium for future use. Dilute BAB159 to the desired concentration using MH broth culture medium, take 100 L of BAB159 and add it to a 96-well flat plate. Add 100 L of diluted bacterial solution to each well. Set up negative and positive controls containing only MH broth culture medium and the test bacterial solution. Set the temperature of the enzyme-linked analyzer system to 37 C. and measure the absorbance at OD 600 nm once per hour for a total of 24 hours. Three biological replicates were set for each treatment, as shown in FIG. 6. In FIG. 6, PBS represents the buffer group, 159 represents the compound BAB159 group, and van represents the vancomycin group. By observing the dynamic curve of bacterial growth, it 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. The growth inhibition effect on vancomycin resistant Enterococcus faecium CAU369 is comparable to that of vancomycin.

Embodiment 6 Time-Kill Curve of BAB159

[0055] Select monoclonal Staphylococcus aureus ATCC 25923 and culture it in 1 mL BHI broth culture medium at 37 C. and 200 rpm until logarithmic growth stage. Then, adjust the concentration of Staphylococcus aureus ATCC 25923 to 0.5 McF, and dilute it 100-fold to 5 mL of prepared MH broth to obtain a bacterial solution with a bacterial concentration of about 10.sup.6 CFU/mL. Add different concentrations of 159 (4MIC, 10MIC, and 25MIC) to the bacterial broth, and add 10MIC vancomycin (Van) and PBS buffer (0MIC) to the bacterial broth as positive and negative control groups, respectively. Set 3 replicates for each treatment and incubate in a shaker at 37 C. and 200 rpm. Take out 100 L of culture medium after the specific time point of the addition of antibacterial compounds, dilute it in PBS at a multiple ratio, coat and count, and invert at 37 C. for 24 hours to calculate the number of colonies. As shown in FIG. 7, with the increase of BAB159 concentration, its antibacterial efficacy did not significantly increase, but over time, the antibacterial effect became more significant at each concentration. Prove that BAB159 is a time-dependent fungicide. For time-dependent antibiotics, the pharmacokinetic/pharmacodynamic (PK/PD) parameter to be selected for dosage formulation is the ratio of the area under the drug time curve (AUC) to the MIC. Therefore, the AUC to MIC ratio was chosen for the subsequent formulation of BAB159 dosage.

Embodiment 7 Pharmacokinetic Characteristics of BAB159

[0056] In order to investigate the metabolic residues of BAB159 in model animals, rabbits were used as animal models to quantitatively analyze the levels of BAB159 in rabbit plasma. Male Chinese white rabbits weighing around 2 kg were adaptively fed for one week. Then, 2 mL of BAB159 suspension was injected into the left hind thigh muscle of the rabbits at a dose of 20 mg/kg b.w. Blood samples were collected from the ear vein at 8 time points, including 0.5, 1, 2, 4, 6, 8, 12, and 24 hours after administration. After pre-treatment of the plasma samples, UPLC-MS/MS detection was performed.

[0057] The results shows that after intramuscular injection, the C.sub.max, T.sub.max, and AUC in the plasma of rabbits are 207 g/L, 6 h, and 1708 g/L.Math.h, respectively (Table 6). According to the antibacterial spectrum of BAB159, the MIC.sub.50 of the compound against Staphylococcus is 15.6 g/L. Pharmacokinetic parameters show that the area under the drug time curve AUC after intramuscular injection is 1708 g/L.Math.h, obtain AUIC=109. Research has shown that when the AUIC of time-dependent antibiotics is greater than 100, the compound is considered to have superior therapeutic effects (Pharmaceutics, 2021, 13 (5): 602). The above results indicate that the compound BAB159 of the present invention has great potential for application in the treatment of clinically relevant pathogenic infections.

TABLE-US-00006 TABLE 6 Pharmacokinetic parameters of BAB159 in rabbits Parameter Unit Numerical value Dose mg/kg b.w 20 T.sub.max h 6 C.sub.max g/L 148.2 13.05 Vd L 0.28 0.03 AUC.sub.0-last g/L .Math. h 1644.8 70.5 T.sub.1/2 h 16.1 3.6 CL mL/min 0.01 0.003 Note: T.sub.max: time to peak; C.sub.max: maximum blood drug concentration; Vd: apparent distribution volume; AUC: area under the drug time curve; T.sub.1/2: half-life; CL: clearance constant.

Embodiment 8 Efficacy of Compound BAB159 in an In Vivo Animal Infection Model

[0058] In vivo infection model of the Galleria mellonella: randomly divide approximately 300 mg of Galleria mellonella larvae into 8 individuals per group. Each Galleria mellonella was injected with 10 L of MRSA T144 bacterial suspension (final concentration of 5.510.sup.6 CFU/individual) from its left proleg.

[0059] After 1 hour of bacterial infection, 10 L of BAB159 solution was injected into the right proleg of the Galleria mellonella at a dose of 2 mg/kg b.w. The positive control was vancomycin with a concentration of 2 mg/kg b.w. Record the survival rate of each group of the Galleria mellonella daily for 5 days. FIG. 8 shows the protective efficacy of compound BAB159 against infection by the Galleria mellonella. In the infection model of the Galleria mellonella, the protective rate of BAB159 against the Galleria mellonella within 5 days of infection was 70%, which was better than the 40% of vancomycin.

[0060] Mouse bacteremia model: C57BL/6J female mice weighing between 18-20 g 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 200 L of MRSA T144 bacterial suspension (final concentration of 1.510.sup.8 CFU/individual). After 1 hour of bacterial infection, mice were administered corresponding compounds and positive control vancomycin at a dose of 10 mg/kg b.w. Record the survival rate of mice within 72 hours. FIG. 9 shows the survival rate of mice infected with BAB159. In the mouse infection model, the protective rate of BAB159 on mice within 3 days was 100%, which was comparable to the efficacy of vancomycin and significantly stronger than the PBS group.

[0061] The above results indicate that BAB159 provided by the present invention has excellent antibacterial activity against common clinical pathogenic bacteria and fungi, and its effect is superior to some listed antibiotics. At the same time, the pharmacokinetic parameters of BAB 159 are suitable and have shown good therapeutic effects on both the Galleria mellonella and rabbit infection models, indicating that BAB 159 can be used for the treatment of related pathogenic bacterial infections and has good clinical application prospects.