山东省滨州市某社区来源产ESBLs大肠埃希菌及mcr-1阳性菌株耐药基因分析

目的 分析城市社区居民肠道来源产超广谱β-内酰胺酶（ESBL）大肠埃希菌和多黏菌素耐药基因mcr-1阳性菌株的分子流行病学特征。方法 本研究对山东省滨州市某城市社区居民粪便样本中分离的16株产ESBL大肠埃希菌进行药物敏感性试验、全基因组测序（WGS）分析和单核苷酸多态性分析（SNPS）。对多黏菌素耐药的产ESBL大肠埃希菌进行S1-PFGE和Southern杂交确定耐药基因的位置，并用接合试验判断基因的可转移性。结果 某城市社区居民肠道来源产ESBL大肠埃希菌的检出率为40.00%，多重耐药菌占75.00%。WGS分析显示，16株ESBL大肠埃希菌携带多种耐药基因、毒力基因。SNPS分析显示16株产ESBL大肠埃希菌聚集成4个簇。mcr-1阳性产ESBL大肠埃希菌携带的耐药基因mcr-1和blaCTX-M均位于质粒上，且均可随质粒发生水平转移。结论 城市社区居民中可检出多黏菌素耐药ESBL大肠埃希菌，基因mcr-1存在水平传播的可能性。

Analysis on drug resistance genes of ESBLs-producing Escherichia coli and mcr-1 positive strains from a community in Binzhou,Shandong

  Objective  To analyze the molecular epidemiological characteristics of extended-spectrum β-lactamases-producing Escherichia coli (ESBL-EC) and polymyxin resistance gene mcr-1 positive strains from the intestinal tract samples of urban community residents.   Methods  In this study, drug susceptibility test, whole genome sequencing (WGS)s and single nucleotide polymorphisms (SNPs) analysis were performed for 16 ESBL-EC strains isolated from the stool samples of residents in an urban community of Binzhou, Shandong province. S1-PFGE and Southern hybridization were performed for ESBL-EC which were resistant to polymyxin to identify the locus of the drug resistance gene. In addition, the conjugation experiment was conducted to determine the gene transferability.   Results  The detection rate of ESBL-EC from the intestinal tract samples of the community residents was 40.00%, and the multidrug-resistance rate was 75.00%. WGS showed that 16 strains of ESBL-EC carried multiple drug resistance genes and virulence genes. SNPs analysis showed that 16 strains of ESBL-EC were divided into 4 clusters. The drug resistance genes, mcr-1 and bla_CTX-M carried by mcr-1 positive ESBL-EC were all in the plasmids and could transfer horizontally with the plasmids.   Conclusion  Polymyxin resistant ESBL-EC and its resistance genes could be detected in urban community residents. Gene mcr-1 has the possibility of horizontal transmission.