2019—2021年辽宁省食源性致泻大肠埃希菌分子分型与耐药表型分析

Molecular typing and antimicrobial resistance phenotype analysis of food-borne diarrheagenic Escherichia coli in Liaoning province,2019—2021

目的了解2019—2021年辽宁省食品中致泻大肠埃希菌的污染状况,对分离出的致泻大肠埃希菌进行分子特征研究及耐药分析,为食源性疾病溯源和临床用药提供科学依据。方法辽宁省内采集包括水果及其制品、肉及其制品、水产品、餐饮食品等1000份样品进行致泻大肠埃希菌分离,对分离出的阳性菌采用脉冲场凝胶电泳(pulsed field gel electrophoresis,PFGE)进行分子特征分析,应用BioNumeries 7.6软件对菌株间的相似度聚类分析;采用微量肉汤稀释法进行药物敏感性检测。结果从1000份食品中分离出38株致泻大肠埃希菌,检出率为3.8%,其中从肉及肉制品中分离出20株,占52.6%。PFGE聚类结果显示36株肠集聚性大肠埃希菌(enteroaggre-gative Escherichia coli,EAEC)菌被分为35种带型,同源性为60%~100%。药物敏感性结果显示,38株致泻大肠埃希菌呈现30株耐药株,耐药率为78.9%,其中耐药率最高的为四环素,为71.1%(27/38);其次是氨苄西林55.3%(21/38),共发现12种多重耐药谱,多重耐药率为60.5%(23/38)。结论辽宁省致泻大肠埃希菌污染情况较为严重,且来源于肉及肉制品食品的致泻大肠埃希菌耐药情况比较严重,应引起相关部门的注意。

Objective To understand the status of food contamination by diarrheagenic Escherichia coli in Liaoning province from 2019 to 2021,and to analyze the molecular characteristics and drug resistance of the isolated diarrheagenic E.coli stains,so as to provide scientific basis for the source tracing of food-borne diseases and medication in clinical practice.Methods One thousand samples,including fruits and their products,meat and its products,aquatic products and food in restaurants were collected in Liaoning province for isolation of diarrheagenic E.coli.The molecular characteristics of the isolated strains were analyzed by pulsed field gel electrophoresis(PFGE).The clustering analysis by BioNumeries 7.6 software was used to analyze the similarity of the strains.The micro broth dilution method was used in drug susceptibility test.Results From 1000 food samples,38 strains of diarrheagenic E.coli were isolated and the detection rate was 3.8%.Among the stains,20 strains were from meat and meat products,accounting for 52.6%.The result of PFGE clustering showed that the 36 strains(EAEC)had 35 banding patterns with 60%-100% similarity.The result of drug susceptibility test showed that 30 of 38 diarrheagenic E.coli strains were drug-resistant and the drug-resistant rate was 78.9%.The resistant rate of tetracycline was the highest(71.1%,27/38),followed by that of ampicillin(55.3%,21/38).There were 12 multi-drug resistance patterns with a rate of multi-drug resistance of 60.5%(23/38).Conclusions The contamination of food by diarrheagenic E.coli in Liaoning province is rather serious,and the drug resistance of diarrheagenic E.coli from meat and meat products is also serious.This should be paid attention to by relevant government agencies.