产新德里金属β-内酰胺酶肠外致病性大肠埃希菌的分子分型  

Molecular typing of New Delhi metallo-β-lactamase-producing extraintestinal pathogenic Escherichia coli

作　　者：冯丽娜[1] 李从荣[1] 姜树朋 杨勇文[1] 蔡璇[1] 李娟[1] 冯锴[1] 郭静[1] Feng Lina;Li Congrong;Jiang Shupeng;Yang Yongwen;Cai Xuan;Li Juan;Feng Kai;Guo Jing(Department of Clinical Laboratory,Renmin Hospital of Wuhan University,Wuhan 430060,China)

机构地区：[1]武汉大学人民医院检验医学中心,武汉市430060

出　　处：《中华实验和临床感染病杂志（电子版）》2020年第1期24-30,共7页Chinese Journal of Experimental and Clinical Infectious Diseases(Electronic Edition)

基　　金：国家临床重点专科建设项目(No.财社[2010]305)。

摘　　要：目的对产新德里金属β-内酰胺酶(NDM)的肠外致病性大肠埃希菌(ExPEC)进行多位点序列分型(MLST)和系统发育分群研究。方法收集2016年2月至2018年2月分离自武汉大学人民医院临床送检标本中对亚胺培南和(或)美罗培南敏感性降低(MIC≥2μg/ml)的ExPEC菌株。改良Hodge试验(MHT)对碳青霉烯酶进行表型确证。PCR检测碳青霉烯酶编码基因blaNDM。Sanger测序法检测各碳青霉烯酶基因亚型。采用MLST分型和系统发育分群对PCR检测出的产NDM ExPEC菌株的分子流行病学特征进行分析。结果共收集到对碳青霉烯类抗菌药物敏感性降低的ExPEC菌株20株,其中产NDMExPEC菌株15株。MHT检测产NDMExPEC菌株的敏感度和特异度分别为93.3%(14/15)和80.0%(12/15)。15株产NDM ExPEC菌株中11株(73.3%)产NDM-5型,4株(26.7%)产NDM-1型。系统发育分群结果显示,15株产NDM ExPEC菌株中,13株属于A群,2株属于D群。MLST分型结果显示,ST410是产NDM ExPEC菌株中检出率最高的ST型(5株,33.3%)。结论本院绝大多数产NDM ExPEC菌株属于毒力较小的系统发育群,应加强院感监测,防止高危克隆ST型的暴发流行。Objective To investigate the multilocus sequence typing(MLST)and phylogenetic grouping of parenteral pathogenic Escherichia coli(ExPEC)producing New Delhi metal beta-lactamase(NDM).Methods The carbapenem-nonsusceptible ExPEC strains with decreased sensitivity to imipenem and/or meropenem(MIC≥2μg/ml)isolated from clinical samples in Renmin Hospital of Wuhan University from February 2016 and February 2018 were screened.The carbapenemase phenotype was identified by modified Hodge test(MHT).The carbapenem coding gene blaNDM were detected by PCR.The carbapenem subtypes were detected by Sanger sequencing.The molecular epidemiological characteristics of NDM ExPEC strains detected by PCR were analyzed by MLST typing and phylogenetic grouping.Results A total of 20 ExPEC strains with reduced sensitivity to carbapenems were collected,among which 15 ExPEC strains produced NDM.The sensitivity and specificity of MHT to detect NDM-producing ExPEC strains were 93.3%(14/15)and 80.0%(12/15),respectively.Fifteen NDM-producing ExPEC strains were identified,among which 11 strains(73.3%)were NDM-5-positive and 4 strains(26.7%)were NDM-1-positive.Phylogenetic grouping result showed that among the 15 NDM ExPEC strains,13 strains belonged to phylogenetic group A and 2 strains belonged to phylogenetic group D.MLST typing indicated that sequence type 410(ST410)was the highest detected type of ST in NDM ExPEC strains(5 strains,33.3%).Conclusions The vast majority of NDM ExPEC-producing strains in our hospital belong to the less virulent phylogenetic group,so the hospital sense monitoring should strengthen to prevent the outbreak of high-risk cloning ST type.

关 键 词：碳青霉烯耐药 新德里金属β-内酰胺酶 肠外致病性大肠埃希菌 系统发育分群 多位点序列分型 

分 类 号：R446.5[医药卫生—诊断学]