A bacteriophage JD007 synergistic antibacterial composition with teicoplanin and screening method and application thereof

Abstract

The application discloses a bacteriophage JD007 and teicoplanin synergistic antibacterial composition, a screening method and application thereof, and the synergistic antibacterial composition comprises staphylococcus aureus bacteriophage JD007 and teicoplanin; the preservation number of the staphylococcus aureus bacteriophage JD007 is CGMCC No. 47048. The synergistic antibacterial composition not only has a strong killing effect on planktonic bacteria, but also can effectively destroy and remove bacterial biofilm, and the synergistic antibacterial composition is used for preparing a medicine for treating staphylococcus aureus infection, can significantly reduce the use dosage of teicoplanin, reduce antibiotic selective pressure, and thereby reduce the risk of generation of drug-resistant strains.

Description

Technical Field

[0001] This invention relates to the field of biotechnology, specifically to a synergistic antibacterial composition of bacteriophage JD007 and teicoplanin, its screening method, and its application. Background Technology

[0002] Staphylococcus aureus (S. aureus) is a common colonizing bacterium of human skin and nasal cavity, and also a common pathogen causing clinical infections. Severe infections can lead to bone and joint infections, skin and soft tissue infections, infective endocarditis, pneumonia, keratitis, and sepsis. With the global prevalence of methicillin-resistant Staphylococcus aureus (MRSA), S. aureus has become one of the leading pathogens causing hospital-acquired and community-acquired infections. MRSA strains are resistant to almost all β-lactam antibiotics and also exhibit high resistance to many other antibiotics, resulting in extremely limited clinical treatment options.

[0003] Teicoplanin is a glycopeptide antibiotic that exerts its bactericidal effect by inhibiting the synthesis of peptidoglycan in bacterial cell walls, exhibiting strong antibacterial activity against Gram-positive bacteria, including MRSA. However, with the widespread clinical use of teicoplanin, strains showing decreased sensitivity or even resistance to it have emerged. Therefore, there is an urgent need to develop novel treatment strategies that can enhance the efficacy of teicoplanin against Staphylococcus aureus. Summary of the Invention

[0004] The purpose of this invention is to overcome the limitations of single teicoplanin or single bacteriophage in the application of anti-Staphylococcus aureus and the easy development of drug resistance, and to provide a pharmaceutical composition to enhance the antibacterial effect against Staphylococcus aureus (especially MRSA).

[0005] To achieve the above objectives, the present invention provides a synergistic antibacterial composition of bacteriophage JD007 and teicoplanin, wherein the synergistic antibacterial composition comprises Staphylococcus aureus bacteriophage JD007 and teicoplanin; wherein the accession number of Staphylococcus aureus bacteriophage JD007 is CGMCC No. 47048.

[0006] This invention also provides a method for screening synergistic antibacterial compositions of bacterial cell JD007 and teicoplanin, comprising the following steps: Step S1, Sensitivity test: Several clinical strains of Staphylococcus aureus to be tested are subjected to a phage sensitivity test with Staphylococcus aureus phage JD007 to screen out strains sensitive to the Staphylococcus aureus phage JD007. Step S2, KB method preliminary screening: The sensitive strains obtained in step S1 are mixed with the Staphylococcus aureus phage JD007 and poured onto MH plates. Different antibiotic susceptibility test strips are attached. By comparing the size of the phage plaques around the inhibition zone, teicoplanin, an antibiotic that has a synergistic effect with the Staphylococcus aureus phage JD007, is preliminarily screened. Step S3, checkerboard method verification: Take the antibiotic teicoplanin and perform a combined drug sensitivity test according to the checkerboard method to calculate the FIC index.

[0007] Optionally, the sensitivity test includes adjusting the concentration of the clinical Staphylococcus aureus strain to 10. 8 CFU / mL, mixed with 0.7% agar, was poured onto MH plates; a concentration of 10... 9 Staphylococcus aureus phage JD007 was diluted at pfu / mL and dropped onto MH plates. Plaques were counted the next day, and strains sensitive to Staphylococcus aureus phage JD007 were screened.

[0008] Optionally, the initial screening using the KB method includes: mixing the sensitive strains obtained in step S1 with the Staphylococcus aureus phage JD007, then pouring the mixture onto MH plates with 0.7% agar, and attaching different antibiotic susceptibility test strips after cooling; observing the results the following day to obtain teicoplanin, an antibiotic whose phage plaques around the inhibition zone are significantly larger than those in the control group.

[0009] Optionally, the checkerboard method verification includes: constructing a combined action matrix of teicoplanin with different concentration gradients and Staphylococcus aureus phage JD007 with different concentration gradients in a 96-well plate, adding a quantitative Staphylococcus aureus suspension to each well, measuring the OD value after incubation, plotting a thermogram, and calculating the FIC index.

[0010] Optionally, the MH plate comprises: 22 g / L beef extract powder, 17.5 g / L hydrolyzed casein, 1.5 g / L soluble starch, 21 g / L lower agar, and 15 g / L upper agar.

[0011] The present invention also provides a medicament for the prevention or treatment of Staphylococcus aureus infection, the medicament comprising the synergistic antimicrobial composition as described above and a pharmaceutically acceptable carrier.

[0012] Optionally, the dosage form of the drug includes any one of the following: solution, powder, tablet, capsule, suspension, emulsion, or biogel.

[0013] The present invention also provides an application of the synergistic antimicrobial composition as described above, wherein the synergistic antimicrobial composition is used to prepare bactericidal / bacteriostatic products.

[0014] Optionally, the synergistic antimicrobial composition may be used in the preparation of medicaments for the treatment and / or prevention of Staphylococcus aureus infections.

[0015] Compared to the prior art, the beneficial effects of the present invention include at least the following: This invention is the first to discover that the combined use of Staphylococcus aureus phage JD007 and teicoplanin can significantly reduce the minimum inhibitory concentration (MIC) against Staphylococcus aureus (including MRSA), exhibiting a synergistic bactericidal effect. It not only has a strong killing effect on planktonic bacteria but also effectively destroys and removes bacterial biofilms, solving the problem of single-treatment regimens being unable to clear biofilm infections. The synergistic antibacterial composition of this invention can significantly reduce the dosage of teicoplanin, reducing antibiotic selectivity pressure and thus reducing the risk of developing drug-resistant strains, and may even restore the sensitivity of already resistant strains. Furthermore, this invention, through combined transcriptomics and metabolomics analysis, shows that the combined drug significantly perturbs bacterial energy metabolism, nitrogen metabolism, and signal transduction networks, cross-validating the synergistic antibacterial mechanism from a multi-omics perspective. Even further, electron microscopy experiments confirm that the combined use of Staphylococcus aureus phage JD007 and teicoplanin increases the contact area and infection efficiency between Staphylococcus aureus phage JD007 and bacteria, forming a dual synergistic antibacterial effect of physical and chemical means. Attached Figure Description

[0016] Figure 1 Images showing the size of plaques generated by the clinical MRSA strain sau127 selected in this invention against Staphylococcus aureus phage JD007.

[0017] Figure 2 Images showing the plaque size of 30 clinical Staphylococcus aureus strains screened for this invention in the kb assay using a combination of teicoplanin and Staphylococcus aureus phage JD007.

[0018] Figure 3 This is a diagram illustrating the checkerboard growth curve of the synergistic effect of teicoplanin and Staphylococcus aureus phage JD007 according to the present invention.

[0019] Figure 4-7 The heatmap of the synergistic effect of Staphylococcus aureus phage JD007 and teicoplanin on the four clinical strains selected in this invention is shown in the checkerboard method.

[0020] Figure 8-10 The growth curves of the three clinical strains of this invention at the maximum FIC index of Staphylococcus aureus phage JD007 and teicoplanin are compared with those of the single Staphylococcus aureus group, the single Staphylococcus aureus phage JD007 group, and the single teicoplanin group.

[0021] Figure 11Electron micrographs of Staphylococcus aureus phage JD007 and teicoplanin synergistically administered (TEC_JD007) according to the present invention, compared with control group (control), JD007 group (JD007), and teicoplanin group (TEC).

[0022] Figure 12 This is a diagram showing the transcriptomic results of the Staphylococcus aureus phage JD007 used in combination with teicoplanin and the teicoplanin monotherapy group, as presented in this invention.

[0023] Figure 13 This is a graph showing the metabolomics results of the synergistic use of Staphylococcus aureus phage JD007 with teicoplanin and the teicoplanin-only group, as presented in this invention.

[0024] Figure 14 This figure shows the transcriptomic and metabolomics pathway enrichment results of the Staphylococcus aureus phage JD007 synergistically with teicoplanin and teicoplanin alone. Detailed Implementation

[0025] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments. Unless otherwise specified, all experimental methods in this invention are conventional experimental methods, and all experimental materials and reagents not specifically described in this invention are commercially available.

[0026] The FIC index (Final Inhibition Concentration Index) is a classic core indicator for in vitro quantitative evaluation of the combined effects of two drugs. It is widely used in studies of combined drug use in antibacterial, antitumor, and antiviral applications. It is generally used in conjunction with the checkerboard assay. Its core function is to distinguish between four types of interactions: synergistic, additive, unrelated, and antagonistic.

[0027] The Staphylococcus aureus phage of the present invention Staphylococcus aureus phage JD007 was obtained from chicken manure samples from a vegetable market and can lyse 95% of Staphylococcus aureus strains clinically isolated from multiple hospitals in Shanghai. It was deposited on May 9, 2026, at the China General Microbiological Culture Collection Center (CGMCC, address: No. 3, Courtyard 1, Beichen West Road, Chaoyang District, Beijing, Institute of Microbiology, Chinese Academy of Sciences, 100101, China), with accession number CGMCC No. 47048.

[0028] Experimental reagents: Columbia blood agar plate: 18-23g special peptone, 0.5-1g starch, 3-5g sodium chloride, 7-10g agar, 50-70mL defibrinated sheep blood, 800-1000mL distilled water. Adjust pH to 7.3±0.2.

[0029] MH plate: Beef extract powder 22 g / L, hydrolyzed casein 17.5 g / L, soluble starch 1.5 g / L, lower agar 21 g / L, upper agar concentration 15 g / L. Adjust pH to 7.4 ± 0.2.

[0030] MH liquid culture medium: beef extract powder 22 g / L, hydrolyzed casein 17.5 g / L, soluble starch 1.5 g / L. Adjust pH to 7.4 ± 0.2.

[0031] PBS solution: Sodium chloride 8.0~8.5g / L, potassium chloride 0.2~0.3g / L, disodium hydrogen phosphate 1.44~1.5g / L, potassium dihydrogen phosphate 0.24~0.3g / L. Adjust the pH to 7.2~7.4.

[0032] Teicoplanin: Based on the stock solution concentration of teicoplanin being 10 mg / mL, dilute to the appropriate concentration with MH liquid culture medium.

[0033] I. Sensitivity test of clinical strains to Staphylococcus aureus phage JD007 Thirty clinical strains of Staphylococcus aureus were plated onto Columbia blood agar plates and streaked in four zones using a sterile inoculating loop. The plates were incubated overnight at 37°C with 5% CO2. Single Staphylococcus aureus colonies were then observed and adjusted to McFarland turbidity of 0.5 (approximately 10⁻⁶). 8 (cfu / mL). Pipette 200 μL into a 5 mL EP tube, add 4 mL of 0.7% agar (45-50°C), pour onto a square MH plate, cool, and set aside for later use. The concentration should be approximately 10... 9 Staphylococcus aureus phage JD007 at pfu / mL was serially diluted 10-fold, for a total of 6 dilutions. 3 μL of each diluted phage was then dropped onto prepared MH plates, with each bacterium being diluted 3 times.

[0034] like Figure 1 As shown, the clinical strains of Staphylococcus aureus (clinical MRSA strain sau127) sensitive to Staphylococcus aureus phage JD007 were screened for further experiments based on the size and transparency of the phage plaques the following day.

[0035] II. Initial screening of Staphylococcus aureus bacteriophage JD007 and antibiotics using the kb method Clinical strains susceptible to Staphylococcus aureus phage JD007 (sau108, 119, 136, 152, 204, 229, 258, 304, 405, 444, 445, 448, 502, 504, 624, 629, 630, 631, 633, 639, 640, 763, 779, 801, 824, 825, 828, 127, 467, 738) were adjusted to a McFarland turbidity of 0.5 (approximately 10).8 After diluting (cfu / mL), pipette 200 μL into a 5 mL EP tube. Separately dilute Staphylococcus aureus phage JD007 to an appropriate concentration (10⁻⁶ CFU / mL). 4 ~10 5 (CFU / mL), pipette 40 μL into the same EP tube, add 4 mL of 0.7% agar at 45-50°C, pour onto a square MH plate, and let cool before use. Select susceptibility testing discs for 13 commonly used clinical antibiotics (penicillin, oxacillin, ampicillin, ampicillin / sulbactam, cefuroxime, vancomycin, erythromycin, clindamycin, cefoxitin, fosfomycin, teicoplanin, levofloxacin, linezolid), affix them to the cooled plates, and perform the kb method test. Incubate overnight at 37°C in a 5% CO2 incubator. Observe and measure the size of the plaques around the inhibition zone the next day. Figure 2 The results are shown for the antibiotic teicoplanin and Staphylococcus aureus phage JD007. Teicoplanin was selected from commonly used clinical antibiotics and antibiotics targeting MRSA.

[0036] It should be noted that the kb method is only suitable for rapid screening of antibiotics; the specific synergistic effect and concentration need to be determined based on the results of the checkerboard method.

[0037] III. Synergistic effect of Staphylococcus aureus bacteriophage JD007 and teicoplanin using the checkerboard method Based on the MIC values ​​of teicoplanin obtained from previous clinical trials, taking strain Sau127 as an example, the initial concentration of teicoplanin in the experimental reaction system was set at 512 mg / L. Figure 3 Add 100 μL of the solution to column 1 of a 96-well plate. Add 50 μL of LMH liquid culture medium to columns 2-10 using a twofold dilution method. Add 2048 mg / L teicoplanin solution to column 1 of the 96-well plate. Transfer 50 μL of the solution from column 1 to column 2, mix well by pipetting, and the concentration in column 2 will be 1024 mg / L. Then transfer 50 μL from column 2 to column 3, mix well, and halve the concentration each time. Repeat the above operation until column 9, discarding the last 50 μL of liquid. The final concentration in column 9 will be 0.125 mg / L. For all dilution steps, change the pipette tip and mix thoroughly to ensure dilution accuracy. The concentration is approximately 2*10⁻⁶. 9 Staphylococcus aureus phage JD007 at pfu / mL was serially diluted 10-fold in sterile EP tubes, for a total of 7 dilutions, to obtain concentrations of 10 pfu / mL. 9 10 8 10 7 10 6 10 5 10 4 10 3Diluent of (pfu / mL). In a 96-well plate, select the first 10 columns from row 1 to row 7 (i.e., columns 1 to 10) as the sample loading area. Add 2*10 pfu / mL solution to each well in the first 10 columns of row 1. 9 Phage broth at a concentration of pfu / mL, and so on, until the first 10 columns of the 7th row are filled with 2*10 pfu / mL broth. 3 pfu / mL. 50 μL was added to each well, with three replicates per concentration. 10 8 CFU / mL Staphylococcus aureus diluted to 10 6 Add 100 μL of diluted Staphylococcus aureus to each well, for a total volume of 200 μL. In column 12, set up separate control groups for single Staphylococcus aureus, single teicoplanin, single Staphylococcus aureus phage JD007, and single MH, each with a concentration of 200 μL.

[0038] Results were observed at 20 hours of incubation, and OD values ​​were measured. The percentage of the absolute difference between the OD values ​​of each experimental group and the control group (Staphylococcus aureus alone) was plotted. For example, clinical strains sau108, 127, 738, and 825 were used. Figure 4-7 The heatmap obtained using the checkerboard method shows that the combined drug group has a more significant bactericidal effect than the teicoplanin or JD007 alone groups. Furthermore, based on the FIC index ((MIC of combined antibiotics / MIC of single antibiotics) + (MIC of combined phages / MIC of single phages)), both are less than 0.5, indicating a synergistic effect.

[0039] IV. Growth curve of synergistic effect between Staphylococcus aureus bacteriophage JD007 and teicoplanin Based on the above results, the minimum inhibitory concentrations (MICs) corresponding to teicoplanin and JD007 were selected. Taking the clinical strain sau127 as an example, the selected concentrations were 0.5 mg / L and 2*10 mg / L, respectively. 6 pfu / mL. In the same checkerboard method, 50 μL of 2 mg / L teicoplanin and 50 μL of 2*10... 6 Add pfu / mL Staphylococcus aureus phage JD007 to a 100-well plate, and then add 100 μL of the diluted solution to a concentration of 10. 6 CFU / mL of Staphylococcus aureus Sau127 was used. Simultaneously, 200 μL of single Staphylococcus aureus control, single teicoplanin control, single JD007 control, and single MH control were set up. 100-well plates were placed in a Bioscreen C fully automated microbial growth curve analyzer, and OD values ​​were continuously measured every 30 minutes for 20 hours at medium amplitude and speed. Each experiment was repeated three times.

[0040] Based on the measured 20-hour OD values, GraphPad Prism was used for analysis and growth curve plotting was generated. Figure 8-10 The bactericidal effect over time shows that the combined drug group has a more significant bactericidal effect than the single drug group.

[0041] V. Electron micrographs of the synergistic effect between Staphylococcus aureus bacteriophage JD007 and teicoplanin. Based on the above checkerboard method experimental results, taking Sau127 as an example, when the MOI (the ratio of phage number to host bacteria) is 1, the concentrations of teicoplanin and JD007 are 1 / 4 MIC (0.5 mg / L) and 10 mg / L, respectively. 8 pfu / mL, with single Sau127 and single Staphylococcus aureus phage JD007 groups also included. The phage treatment sequence was mimicked in clinical settings, with 2*10 pfu / mL phages administered. 8 In a CFU / mL bacterial suspension, an equal volume of teicoplanin (2 mg / L) was added and co-cultured at 37°C for 2 hours. Then, an equal volume of JD007 was added and co-cultured for another 30 minutes. The control group was treated with the corresponding MH liquid medium. The mixture was centrifuged at 10,000 rpm for 2 minutes, and the supernatant was discarded. The cells were then gently washed twice with PBS solution, and the supernatant was discarded again. Approximately 100 μL of bacterial suspension was retained and dropped onto poly-L-lysine cell spreaders. The suspensions were allowed to stand for approximately 30 minutes to allow for adsorption and relative drying. The adsorbed spreaders were then transferred to 24-well cell culture plates. The sample was fixed with 2.5% glutaraldehyde PBS and incubated overnight at 4°C; then washed twice with PBS buffer, 10 minutes each time; followed by fixation with 1% osmium tetroxide PBS for 2 hours; then washed twice with PBS buffer; and then dehydrated stepwise with 30%–50%–70%–80%–95%–100%–100% ethanol; finally, critical point drying was performed using a Leica EM CPD300 and ion sputtering conductivity was achieved using a Leica EMACE200. Observations were performed using a ZEISS Gemini SEM300 field emission scanning electron microscope. Figure 11 As shown, compared with the control group, the bacteria in the group treated with teicoplanin and Staphylococcus aureus phage JD007 were larger and flatter, indicating that the bacterial wall was destroyed, leading to changes in bacterial morphology.

[0042] VI. Transcriptional and Metabolomics Mechanisms Research Transcriptomic and metabolomic analyses were conducted using sau127 as an example. The experimental group consisted of teicoplanin in combination with Staphylococcus aureus phage JD007, while the control group consisted of teicoplanin alone.

[0043] Transcriptome sequencing analysis showed that, compared with teicoplanin monotherapy, the combination of teicoplanin and Staphylococcus aureus phage JD007 significantly and specifically regulated the gene expression profile of Staphylococcus aureus. Volcano plot and KEGG pathway analysis further demonstrated this effect. Figure 12 and Figure 13The combined use of teicoplanin and Staphylococcus aureus phage JD007 exhibits a multi-faceted synergistic bactericidal effect against Staphylococcus aureus, causing cell wall damage, membrane structure disruption, metabolic disturbances, and genome replication stress. To resist these dual stresses and maintain basic life activities and damage repair, the bacteria initiate compensatory defense responses. Specifically, the combined treatment group showed significant upregulation of key genes in the purine metabolism pathway, purD and purH, as well as significantly increased expression of peptidoglycan synthesis-related genes dapB and the global transcriptional regulator gntR. Simultaneously, the combined treatment group resulted in severe disruption of overall bacterial energy metabolism and suppression of carbon source utilization pathways, such as significant downregulation of glycopolysaccharide metabolism-related GAN operons (ganQ, ganP, ganS), oxidative stress defense-related genes pxpA, and membrane homeostasis-related genes. These differentially expressed genes were mainly enriched in central carbon metabolism, nucleotide synthesis, cell membrane transport, and bacterial stress defense pathways, suggesting that the combined treatment can systematically interfere with bacterial energy metabolism, substance transport, and damage repair processes at the transcriptional level.

[0044] The results of metabolomics KEGG enrichment analysis were highly consistent with and corroborated by transcriptomic changes. Figure 14 Metabolomics analysis of the KEGG pathway revealed significant enrichment of Staphylococcus aureus in the combined treatment group across pathways including the ABC transmembrane transporter pathway, purine metabolism, pyrimidine metabolism, folate-mediated one-carbon unit metabolism, glycine / serine / threonine metabolism, and glutathione metabolism. The significant enrichment of purine, pyrimidine, and one-carbon unit metabolism corresponded to the upregulation of purine synthesis genes at the transcriptional level, indicating compensatory activation in bacteria. Changes in glutathione metabolism were corroborated by the downregulation of oxidative stress-related genes. Figure 14 The combined analysis also showed significant changes in the ABC transporter pathway, which corresponded to alterations in the expression of membrane function-related genes, indicating a disorder in membrane transport function. The overall regulation of central carbon metabolism and amino acid synthesis pathways indicated the disruption of the bacterial oxidative defense system and energy supply, further confirming that the combined treatment led to the disruption of bacterial energy supply and material synthesis homeostasis.

[0045] It is evident that the transcriptomic and metabolomic results corroborate and support each other, indicating that the combined use of teicoplanin and bacteriophages can synergistically regulate key biological pathways in Staphylococcus aureus, such as central carbon metabolism, nucleotide synthesis, oxidative stress defense, and cell membrane transport, thereby achieving a synergistic antibacterial effect through interference with multiple pathways.

[0046] In summary, this invention provides a synergistic antibacterial composition of bacteriophage JD007 and teicoplanin, comprising Staphylococcus aureus bacteriophage JD007 and teicoplanin; the preservation number of Staphylococcus aureus bacteriophage JD007 is CGMCC No. 47048. This synergistic antibacterial composition can significantly reduce the minimum inhibitory concentration (MIC) against Staphylococcus aureus, achieving highly efficient bactericidal activity at lower drug concentrations. Through combined use, the dosage of teicoplanin can be significantly reduced, lowering antibiotic selectivity pressure and thus reducing the risk of developing drug-resistant strains. Furthermore, the synergistic antibacterial mechanism is verified at the molecular level.

[0047] Although the present invention has been described in detail through the preferred embodiments above, it should be understood that the above description should not be considered as a limitation of the present invention. Various modifications and substitutions to the present invention will be apparent to those skilled in the art after reading the above description. Therefore, the scope of protection of the present invention should be defined by the appended claims.

Claims

1. A synergistic antibacterial composition of bacteriophage JD007 and teicoplanin, characterized in that, The synergistic antibacterial composition comprises Staphylococcus aureus phage JD007 and teicoplanin; the accession number of Staphylococcus aureus phage JD007 is CGMCC No. 47048.

2. A method for screening synergistic antibacterial compositions as described in claim 1, characterized in that, Includes the following steps: Step S1, Sensitivity test: Several clinical strains of Staphylococcus aureus to be tested are subjected to a phage sensitivity test with Staphylococcus aureus phage JD007 to screen out strains sensitive to the Staphylococcus aureus phage JD007. Step S2, KB method preliminary screening: The sensitive strains obtained in step S1 are mixed with the Staphylococcus aureus phage JD007 and poured onto MH plates. Different antibiotic susceptibility test strips are attached. By comparing the size of the phage plaques around the inhibition zone, teicoplanin, an antibiotic that has a synergistic effect with the Staphylococcus aureus phage JD007, is preliminarily screened. Step S3, checkerboard method verification: Take the antibiotic teicoplanin and perform a combined drug sensitivity test according to the checkerboard method to calculate the FIC index.

3. The screening method as described in claim 2, characterized in that, The sensitivity test includes adjusting the concentration of the clinical strain of Staphylococcus aureus to 10. 8 CFU / mL, mixed with 0.7% agar, was poured onto MH plates; a concentration of 10... 9 Staphylococcus aureus phage JD007 at pfu / mL was serially diluted 10-fold, for a total of 6 dilutions, and 3 μL of each dilution was dropped onto MH plates. Plaques were counted every other day, and strains sensitive to Staphylococcus aureus phage JD007 were screened.

4. The screening method as described in claim 2, characterized in that, The initial screening using the KB method includes: mixing the sensitive strains obtained in step S1 with the Staphylococcus aureus phage JD007, then pouring the mixture onto MH plates with 0.7% agar, and attaching different antibiotic susceptibility test strips after cooling; observing the results the following day to find that teicoplanin was the antibiotic whose phage plaques around the inhibition zone were significantly larger than those in the control group.

5. The screening method as described in claim 2, characterized in that, The checkerboard method verification includes: constructing a combined action matrix of teicoplanin and Staphylococcus aureus phage JD007 at different concentration gradients in a 96-well plate, adding a quantitative amount of Staphylococcus aureus suspension to each well, measuring the OD value after incubation, plotting a thermogram, and calculating the FIC index.

6. The screening method as described in claim 2, characterized in that, The MH plate contains: 22 g / L beef extract powder, 17.5 g / L hydrolyzed casein, 1.5 g / L soluble starch, 21 g / L lower agar, and 15 g / L upper agar.

7. A drug for the prevention or treatment of Staphylococcus aureus infection, characterized in that, The drug comprises the synergistic antibacterial composition as described in claim 1 and a pharmaceutically acceptable carrier.

8. The drug as described in claim 7, characterized in that, The dosage form of the drug includes any one of the following: solution, powder, tablet, capsule, suspension, emulsion, or biogel.

9. The application of the synergistic antibacterial composition as described in claim 1, characterized in that, The synergistic antibacterial composition is used to prepare bactericidal / bacteriostatic products.

10. The application as described in claim 9, characterized in that, The use of the synergistic antibacterial composition in the preparation of medicaments for the treatment and / or prevention of Staphylococcus aureus infection.

Images