| With the widespread and unreasonable use of antibacterial drugs in livestock breeding,bacterial resistance has become increasingly serious and complicated.Not only does it cause huge losses to the livestock and poultry industry,but also increases the difficulty of disease prevention and control,it threatens the safety of human life and global public health.Studies have shown that the acquisition of antibiotic-resistance plasmids is a common mechanism for bacteria to develop antibiotic resistance,and the antibiotic resistance mediated by plasmids reverses with the elimination of antibiotic-resistance plasmids.In this study,a strain of E.coli isolated from quail disease material was used as the target bacteria,and the antibiotic resistance plasmid was eliminated through the established Chinese medicine compound.The main contents and results of the research are as follows:Suspected strains were isolated from diseased/dead quails with clinical symptoms of E.coli from multiple quail farms in Sichuan and Chongqing.Screening plates（Mac Conkey plates）,Gram stain microscopy,and 16S rRNA expansion were used In addition,a total of44 strains of quail-derived E.coli were obtained.Screened 10 strains of E.coli;the K-B method was used to conduct the drug susceptibility test on the 10 strains,The strain D17is used as the target bacteria for the subsequent antibiotic resistance elimination test that the antibiotic resistance spectrum was selected as 12 and was resistant to tetracycline and ampicillin.16 active ingredients of single Chinese herbs were extracted by decoction,and the in vitro antibacterial effect of 16 Chinese herbs on D17was determined by the double dilution method of broth.In the pairwise joint bacteriostasis test,Coptis chinensis,Scutellaria baicalensis,and Forsythia suspensa with a combined bacteriostatic index（FICI）≤1were selected as the components of the compound traditional Chinese medicine,and the MIC result was 31.25 mg/mL.The photocopy culture method was used to study the elimination effect of compound Chinese medicine on E.coli resistance plasmid in vitro.The test was divided into Chinese medicine sub-MIC group,SDS group and blank control group.A total of 5 eliminateers were selected in compound Chinese medicine group.K-B method was used to determine the resistance phenotypes of 5 Chinese herbal medicine groups,and the XD1strain with the most changes was selected to detect the plasmid electrophoresis pattern and TET+AMP resistance gene changes.XD1was used to challenge the quail and combined with TET+AMP The treatment of quails showed that after the elimination of antibiotic resistance,a plasmid band of about 1 600 bp disappeared,and the antibiotic resistance genes also disappeared,proving that the antibiotic resistance genes will disappear with the elimination of the drug resistant plasmid;TET+AMP The cure rate of challenged quail is 100%,combined with the results of drug susceptibility tests,it is proved that the drug-resistant phenotype will disappear with the elimination of antibiotic resistance. |
