| Escherichia coli(E.coli)is a common zoonotic opportunistic pathogen,which can cause a variety of diseases,such as septicemia,diarrhea,mastitis,endometritis and other diseases,which has an adverse impact on the health of human and animal.However,in recent years,with the widespread use of antibiotics,especially non-standard and incorrect use,the resistance rate of E.coli has been increasing,and the problem of multi-drug resistance has become increasingly serious,making the effectiveness of some drugs commonly used in clinical(such as: β-lactams,aminoglycosides)less effective or even ineffective.With the research and development of new antibiotic drugs entering the bottleneck period,finding effective methods to eliminate bacterial resistance has become crucial.Traditional Chinese medicine has been preliminarily confirmed as the elimination agent of bacterial drug resistance,its mechanism mainly includes inhibiting the expression of drug-resistant genes,inhibiting the active efflux pump system,inhibiting the formation of bacterial biofilm,inhibiting the activity and expression of enzymes,eliminating drug-resistant genes and drug-resistant plasmids,etc.In this paper,50 strains of E coli were tested for ESBL production and their drug resistance genes.The strains with high detection rate and variety of drug resistance genes were selected as test bacteria.10 kinds of antibiotics and 12 kinds of traditional Chinese medicine were used for antibacterial experiment in vitro.The bacteria were cultured with traditional Chinese medicine with good antimicrobial effect for 72 h.The elimination rate of drug resistance and drug resistance genes was detected every 24 h.the differences of elimination of 4 drug resistance genes and the changes of drug resistance phenotypes before and after elimination were detected,the results as follows:1.The 50 strains of E.coli were all ESBL-positive bacteria;According to the test results of drug-resistant genes,three strains(which have drug-resistant)were selected as the test bacteria: E1(CTX-M-55),E2(CTX-M-55,TEM-1)and E3(CTX-M-55,TEM-1,qnr S,rmt B);test bacteria were multi-drug resistant bacteria,strains E1,E2 and E3 showed resistance to 7,4 and 9 antibiotics,respectively;Among the 12 traditional Chinese medicines,Chinese gall and black plum 1:1 had the best bacteriostatic effect on the test strains in vitro,with the diameter of bacteriostatic zone of 18.5～21.83 mm,followed by Chinese nutgall,black plum and Scutellaria baicalensis,with the diameter of bacteriostatic zone of 10～18 mm.There was no significant difference in the in vitro antimicrobial test results between the tested strain and the quality control strain E.coli ATCC 25922,strains E1,E2 and E3 had no resistance to traditional Chinese medicine.2.In the drug resistance elimination test,four traditional Chinese medicines of Chinese gall and black plum 1:1,Chinese gallnut,black plum and Scutellaria baicalensis showed higher drug resistance elimination effect on E.coli than the natural elimination rate.Among in these,black plum had the best drug resistance elimination effect on E.coli strains E1 and E2,the elimination rates of 1.5%～9.5% and 10%～11.5%,respectively.Scutellaria baicalensis had the best drug resistance elimination effect on E3,The elimination rates ranged from 3% to 28.5%;Within 72 h,the elimination effect of the selected traditional Chinese medicine on the 3 strains of drug resistance increased with the extension of time;The elimination rate of CTX-M-55 was 62.5%～100%,and the elimination rate of TEM-1 was 0～41.66%;Traditional Chinese medicine(Chinese gall and black plum 1:1,Chinese nutgall,black plum,cutellaria baicalensis)had different effects on the elimination of different types of resistance to strain E3,all results showing thatβ-lactams>aminoglycosides>quinolones;and 0～1 plasmid was lost in the elimination process.After the elimination of drug resistance,the strain had significantly improved its sensitivity to antimicrobial drugs and genetic stability. |
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