北京市某区产2k新亚型志贺毒素大肠埃希菌的检出及其分子特征分析  

Molecular characterization of Escherichia coli producing a novel Shiga toxin 2k subtype detected in one district of Beijing

作　　者：张爽[1] 王丽丽[2] 杨茜 付奎元 李颖[1] 王会波[1] 李辉 王园园[1] 王凤双[1] 彭涛[1] 熊衍文[3] Zhang Shuang;Wang Lili;Yang Xi;Fu Kuiyuan;Li Ying;Wang Huibo;Li Hui;Wang Yuanyuan;Wang Fengshuang;Peng Tao;Xiong Yanwen(Shunyi District Center for Disease Control and Prevention,Beijing 101300,China;Beijing Center for Diseases Prevention and Control,Beijing 100013,China;National Institute for Communicable Disease Control and Prevention,Chinese Center for Disease Control and Prevention,Beijing 102206,China;Baotou Medical College,Inner Mongolia University of Science&Technology,Baotou 014040,Inner Mongolia,China)

机构地区：[1]北京市顺义区疾病预防控制中心,北京101300 [2]北京市疾病预防控制中心,北京100013 [3]中国疾病预防控制中心传染病预防控制所,传染病预防控制国家重点实验室,北京102206 [4]内蒙古科技大学包头医学院,内蒙古包头014040

出　　处：《疾病监测》2023年第7期872-877,共6页Disease Surveillance

基　　金：国家自然科学基金(No.82072254)。

摘　　要：目的分析北京市某区2013—2021年腹泻监测中,首次自腹泻病例分离的2株非O157产志贺毒素大肠埃希菌(STEC)病原学及分子生物学特征。方法应用实时荧光定量PCR方法筛查腹泻病例标本中的肠道致病菌和病毒,对志贺毒素基因(stx)阳性的标本进行细菌分离培养,所得菌株经生化鉴定后,进行血清凝集和微量肉汤稀释法药敏实验,并进行全基因组测序。根据基因组数据分析菌株血清型、多位点序列分型(MLST)、耐药基因及stx亚型,并构建系统发生树。结果2021年腹泻监测中,2例中年女性腹泻患者样本显示stx基因阳性,未能确定可疑暴露食品。分离所得2株STEC菌株携带stx亚型分别为stx1a和stx2k。其中,Stx1a-STEC为O45:H6血清型、ST101型,药敏表型为耐氨苄西林+四环素+头孢噻肟+头孢唑林+庆大霉素+复方磺胺,携带耐药基因aac(3)-Ⅱd、tetA、lnu(F)、aadA22、aph(6)-Id、sul3、qnrS1、ant(3’’)-Ia、bla_(CTX-M-55),样本同时轮状病毒阳性;Stx2k-STEC为O150:H8血清型、ST906型,对检测的15种抗生素均敏感,未检测出耐药基因。全基因组系统进化分析显示2株分离株与STEC参考株存在较大遗传差异。结论北京市某区存在STEC引起的感染,并检出了志贺毒素2k新亚型,应加强对STEC的监测。Objective To understand the etiological and molecular characteristics of two strains of non-O157 Escherichia coli producing Shiga toxin(STEC),which were isolated for the first time in the surveillance for diarrhea in one district of Beijing from 2013 to 2021.Methods The stool samples from diarrhea patients were screened for enteropathogenic bacteria and viruses by using real-time PCR.The stx-positive samples were selected for isolation.After biochemical identification,the STEC strains were investigate by serum agglutination,micro-broth dilution assays and whole genome sequencing.Based on whole genomic sequences,serotypes,multi-locus sequence types,drug resistance genes,and stx subtypes were predicted,and the phylogenetic tree were constructed.Results In 2021,the stool samples from two middle-aged women with diarrhea were detected to be positive for stx gene,however,the suspected exposed food could not be identified.Two STEC strains carrying stx1a and stx2k were isolated respectively.The Stx1a-STEC was identified as serotype O45:H6,ST101,with a drug-sensitive phenotype of ampicillin+tetracycline+cefotaxime sodium+cefazolin+gentamicin+compound sulfamethoxazole,which carried resistance genes aac(3)-Ⅱd,tetA,lnu(F),aadA22,aph(6)-Id,sul3,qnrS1,ant(3'')-Ia,bla_(CTX-M-55).The specimen was also rotavirus positive.The Stx2k-STEC was identified as serotype O150:H8,ST906,it was sensitive to all the tested 15 antibiotics,no resistance gene was detected.Phylogenetic analysis revealed high genetic diversity between the two isolates and STEC reference strains.Conclusion Infections caused by STEC existed in this district of Beijing,and the novel Shiga toxin 2k was detected.The surveillance for STEC should be enhanced.

关 键 词：志贺毒素 大肠埃希菌 肠道病原菌 病原学 全基因组测序 

分 类 号：R211[医药卫生—中医学] R181