Analysis Of Drug Resistance And Detection Of PMQR Genes In Pathogenic Escherichia Coli Isolated From Swines In Heilongjiang Province

In a period of time,Escherichia coli was regarded as part of the intestinal flora in normal human and animal,but later some researcher has found that some serotypes of E.coli are pathogenic to human and animal,in pigs which has often been shown as yellow scour and white scour of piglets,which bring huge damage to the economy of pig industry,which has been accompanied by a wide range of antibacterial drugs or even irregular use,leading to the increase of Escherichia coli resistance,especially the phenomenon that multiple drug resistance is becoming increasingly serious,and the movable element has played an important role in the horizontal transmission mechanism of drug resistance,as a result,which brings phenomenon that the bacteria obtains acquired resistance more continuously.Therefore,the analysis of bacterial drug resistance and study of horizontal transmission mechanism have been a hotspot of scientific research.In recent years,Fluoroquinolones have been widely used in pig industry,followed by the increase of drug resistance,although research indicated luoroquinolone resistance gene mediated low level of resistance at usual time,but multidrug resistance gene in combination with each other or with other antimicrobial drug resistance gene interactions can lead to high levels of resistance even to the clinical drug resistance.This experiment was carried out to analyze the drug resistance of Escherichia coli isolated from large-scale farms in Heilongjiang Province,and to lay emphasis on the detection of plasmid mediated quinolone resistance of Escherichia coli gene,and to study the possibility of horizontal transmission of drug resistance through conjugation test,which bring the more rational use of drug in this regions,and provide certain theoretical basis of drug resistance elimination.According to the CLSI standard,this experiment has determined the minimum inhibitory concentration(MIC) of 106 strains of clinical pathogenic isolated strains to 8 kinds of common drugs by micro broth dilution method,in order to investigate the drug resistance rate of Escherichia coli in Heilongjiang area to 8 kinds of common drugs and to study the detection rate of multidrug resistant Escherichia coli,test results showed that the resistance rate of 106 strains of pathogenic Escherichia coli to 8 kinds of veterinary antibiotic was high,at over 30%,including the highest drug resistance rate of florfenicol(72.64%);and the higher drug resistance rate of ceftriaxone(70.75%),ceftiofur(70.75%),gentamicin(66.04%),amikacin(64.15%);and the high drug resistance rate of enrofloxacin(56.60%),ciprofloxacin(48.11%)and doxycycline(32.08%),and thedetection rate of multiple drug resistance phenotypes(including three drug resistance phenotypes and above) was up to 73.58%.This experiment also used the disk diffusion method to ensure consistency with the test results obtained by using broth microdilution method,so as to confirm the accuracy of the data of drug resistance.The prevalence of plasmid mediated quinolone resistance genes of 106 strains of pathogenic Escherichia coli isolated from swine has been detected,in which the detection rate of oqx AB,qnr S,aac(6’)-Ib-cr,qnr B,qepA was respectively 44.34%,40.57%,14.15%,8.49% and 7.55%,and there was no qnr A,qnr C,qnr D gene being detected,which suggests that PMQR genes exists in a very high detection rate in E.coli isolated from pigs in Heilongjiang province,which is bound to exacerbate the difficulties of clinical medicine,and also bring the possibility for the horizontal transmission of drug resistance genes.This experiment was carried out to investigate the possibility of transmission of antibiotic resistance through the conjugation experiment,and at the same time to explore the function of mobile plasmid in the process that drug resistance genes transferred horizontally by comparing the changes of resistant phenotype and genotype before and after conjugation experiments,the results are as follows: 16 strains of bacteria were jointed successfully within 41 strains of fluoroquinolone resistance and PMQR gene positive donors,and the joint success rate was as high as 39%,according to the test data,what can be realized was that on one hand the intensity of monitoring the resistance genes should be increased;on the other hand the horizontal propagation mechanism of resistance genes must also be studied,so as to provide a theoretical basis for the new veterinary medicine research and the elimination of drug resistance.