多黏菌素耐药基因mcr-1阳性大肠埃希菌分子流行病学及耐药基因特征  

Molecular epidemiological and drug resistance characteristics in polymyxin resistance gene mcr-1-positive Escherichia coli

作　　者：侯轩[1] 张微[1] 邓明惠 王辉[1] 辜依海[1] HOU Xuan;ZHANG Wei;DENG Ming-hui;WANG Hui;GU yi-hai(3201 Hospital Affiliated to Xi'an Jiaotong University,Hanzhong,Shaanzi 723000,China)

机构地区：[1]西安交通大学医学院附属三二〇一医院微生物免疫科,陕西汉中723000

出　　处：《中华医院感染学杂志》2022年第11期1616-1621,共6页Chinese Journal of Nosocomiology

摘　　要：目的了解住院患者分离的mcr-1基因阳性大肠埃希菌分子流行病学特征以及耐药基因毒力基因携带状况,为临床诊治以及院感防控提供依据。方法回顾性分析2008年11月-2018年12月西安交通大学附属三二〇一医院各类临床标本中分离的大肠埃希菌1018株,聚合酶链反应(PCR)法检测多黏菌素耐药基因mcr-1;微量肉汤稀释法以及琼脂稀释法检测多黏菌素及其他抗菌药物对mcr-1阳性菌株的最低抑菌浓度(MIC);多重PCR对mcr-1阳性菌株进行系统发育群分类,并通过全基因组序列构建系统进化树、分析其多位点序列分型(MLST)、毒力基因以及耐药基因。结果1018株大肠埃希菌中,共检出mcr-1基因11株,检出率为1.08%;mcr-1基因阳性大肠埃希菌系统发育群分别属于A、B1和D群,系统进化树显示mcr-1阳性菌株分别属于7个不同进化枝,MLST显示mcr-1阳性菌株分别属于6种不同ST型;耐药基因以及毒力基因显示,mcr-1阳性菌株呈现出多重耐药性,均携带超广谱β-内酰胺酶,同时含有编码保护因子(iss、traT等)、黏附(lpfA、papA/papC以及yfcV),铁摄取系统(sitA、chuA、fyuA、irp2、iucC、iutA以及iroN)、毒素、侵袭等多种毒力基因。结论mcr-1基因在医院内大肠埃希菌中呈现低流行率,并介导低水平的多黏菌素耐药;mcr-1阳性大肠埃希菌呈现多药耐药性并携带多种毒力基因,且存在医院内交叉感染。OBJECTIVE To understand the molecular epidemiological characteristics of mcr-1 gene-positive Escherichia coli and the status of carrying drug-resistant genes and virulence genes in hospitalized patients,and to provide a basis for clinical diagnosis and treatment of the disease and prevention and control of nosocomial infections.METHODS Total of 1018 strains of E.coli isolated from various clinical specimens from Nov.2008 to Dec.2018 were retrospective analyzed.Polymyxin resistance gene mcr-1 was detected by PCR assay and micro broth dilution method and agar dilution method was used to detect the minimum inhibitory concentration(MIC)of mcr-1 positive strains to polymyxin and other antibiotics.Phylogenetic group classification of mcr-1 positive strains was performed by multiplex PCR,and Construct a phylogenetic tree was constructed by whole genome sequences.Multilocus sequence typing(MLST),virulence gene and drug resistance gene were analyzed.RESULTS Among 1018 strains of E.coli,11 strains were positive for mcr-1 gene with the detection rate was 1.08%;The mcr-1 gene-positive E.coli phylogenetic groups belonged to groups A,B1 and D,respectively.The phylogenetic tree showed that mcr-1 positive strains belonged to seven different clades,and MLST showed that mcr-1 positive strains belonged to 6 different ST types.The mcr-1 gene-positive E.coli exhibited multi-drug resistance and produced extended-spectrumβ-lactamase.It also contained many virulence genes such as coding protective factor(iss,traT,etc),adhesion(lpfA,papA/papC and yfcV),iroN uptake system(sitA,chuA,fyuA,irp2,iucC,iutA and iroN),toxin,invasion and so on.CONCLUSION The prevalence of mcr-1 gene in E.coli in the hospitals is low,which mediats low levels of polymyxin resistance;mcr-1 positive E.coli carries multiple virulence genes and exhibits multi-drug resistance,and there is cross infection in the hospital.

关 键 词：大肠埃希菌 多黏菌素 mcr-1基因 系统发育群 毒力基因 耐药基因 

分 类 号：R446.5[医药卫生—诊断学]