Study On Drug Resistance And Drug Resistance Elimination Of Pathogenic ETEC From Pigs In Jiangxi

Enterotoxigenic Escherichia coli(ETEC)is the main infectious pathogen causing diarrhea in piglets,which has a major impact on the healthy development of my country's pig industry.The application of antibiotics has effectively controlled ETEC infectious diseases,but with the abuse of antibiotics,the problem of drug resistance has become increasingly serious.In this experiment,105 samples from 3 pig farms in Jiangxi area were isolated and cultured.After PCR identification and sequencing analysis,90 strains of E.coli were finally isolated.Designed and synthesized specific primers for ST b,LT,K88 and K99 according to the ETEC gene sequence in Gen Bank,successfully established a double PCR detection method,and detected 40 strains of ETEC,with the highest detection rate of K88(34.44%),indicates that the main virulence factor of ETEC in Jiangxi region is K88;the strains carrying different virulence genes are selected for pathogenicity test,the results showed that ETEC isolates were all pathogenic and closely related to virulence factors.18 antibiotics were selected to analyze the drug resistance of ETEC,and 14 drug resistance genes such as bla TEM,Sul1,TetA and qnr A were detected by PCR.The results showed that the ETEC resistance of the three pig farms was serious,and the resistance rate to tetracycline and doxycycline was as high as 100%.The resistance to ampicillin,amoxicillin,cefotaxime,co-trimoxazole,enrofloxacin The drug resistance rate is over 80%;and all strains are multi-resistant strains,the drug resistance spectrum is between 9 and 18 resistance,of which 14 resistance accounts for the largest proportion.Among 14 kinds of resistance genes,11 kinds of resistance genes were detected,among which bla TEM,TetA and Tet C genes had the highest detection rate(100%),Flo R,Sul2,aac(3')-?,ant(3')-?,qnr A,qnr B,qnr S,and bla CTX-M genes,but bla SHV,Tet B,and Sull genes were not detected.This showed that bla TEM,Tet A and Tet C genes are the major epidemic resistance factors in Jiangxi.10 kinds of traditional Chinese medicines were used to conduct an in vitro antibacterial test on 6 strains of ETEC resistant bacteria.The results showed that Schisandra,ebony and gallnut had better antibacterial effects on ETEC.The drug resistance elimination test was carried out on the ETEC by photocopying culture method,and the effect of drug resistance elimination was Schisandra>Galla Chinensis>Wumei.Comparing the changes before and after the elimination of the resistance of the strains,it was found that the ETEC plasmid bands were lost after the action of traditional Chinese medicine;the elimination of the three kinds of traditional Chinese medicine restored the sensitivity to different antibiotics;The Tet A gene of the strain was eliminated by the effect of Galla Chinensis and Wumei,partially eliminated by the action of Schisandra chinensis,but the Tet C gene was not eliminated,indicating that the three Chinese medicines have different effects on the elimination of drug resistance genes.This experiment obtained the basic epidemic situation of pig-derived ETEC virulence factors and drug resistance in Jiangxi,and studied the elimination effect of Chinese medicine on tetracycline-resistant pathogenic ETEC.The medicinal solution provides an effective basis.