临床分离肠外致病大肠杆菌及其与肠内致病大肠杆菌相关性的分子流行病学研究  

The relevance of molecular epidemiological study between Extraintestinal pathological escherichis coli infection in the clinic and intestinal pathogenic escherichis coli

作　　者：唐志君[1] 黄文祥[1] 董一山[1] 郑行萍[1] 刘成伟[1] 余登高[1] 

机构地区：[1]重庆医科大学附属第一医院感染科、重庆市传染病寄生虫病重点实验室,重庆400016

出　　处：《重庆医科大学学报》2010年第8期1252-1255,共4页Journal of Chongqing Medical University

摘　　要：目的:分析临床分离肠外致病大肠杆菌(Extraintestinal pathogenic escherichia coli,ExPEC)的血清型、毒力基因及其与肠内致病大肠杆菌的同源性,探讨ExPEC与肠内致病大肠杆菌的相关性。方法:以我院2006～2009年临床分离的227株ExPEC为研究对象。用常见肠内30种致病大肠杆菌"OK"诊断血清,对上述227株临床分离ExPEC做血清分型,并用PCR分析相关毒力基因,通过脉冲场凝胶电泳(Pulsed field gel electrophoresis,PFGE)分析部分患者ExPEC与该患者肠内大肠杆菌的同源性。结果:在227株ExPEC中,分离出19株肠产毒性大肠杆菌(Enterotoxigenic escherichia coli,ETEC)、15株肠致病性大肠杆菌(Enteropathogenic escherichia coli,EPEC)。ETEC不耐热肠毒素基因(Heat-labile enterotoxin,ltA)表达率31.57%、耐热肠毒素基因(Heat-stable enterotoxin,stI)表达率47.36%、stI/ltA21.05%;EPEC紧密粘附素毒力基因(E.coli attachment A,eac A)表达率60.0%,束状菌毛毒力基因(Bundle-forming pilus,bfpA)66.66%,eaeA/bfpA26.66%。PFGE分型:2例患者血培养大肠杆菌与该患者粪便中分离出的大肠杆菌PFGE分型一致。结论:肠内致病大肠杆菌血清型能引起临床肠外感染,但所占比例相对较少,且主要为ETEC和EPEC血清型。ExPEC感染的败血症患者,其来源可能是其肠道致病大肠杆菌的移位所致。sObjective：To investigate the epidemiological correlation of the Extraintestinal Pathogenic Escherichia coli（ExPEC）and the intestinal Pathogenic Escherichia coli.Methods：227 ExPEC strains isolated in the Department of Infectious Diseases of the First Affiliated Hospitial of Chongqing Medical University were studied to investigate their serotype by＂OK＂diagnostic serum.The virulence gene of the bacterium was analyzed by PCR.The homology of the intestinal Escherichia coli and ExPEC in some patients were analyzed by Pulsed field gel electrophoresis.Results：34 strains were selected in 227 ExPEC strains include 20（Enterotoxigenic escherichia coli,ETEC）strains,14（Enteropathogenic escherichia coli,EPEC）strains.The positive rate of virulence gene of ETEC were the heat labile enterotoxin gene （ltA）31.57%,heat stable enterotoxin gene（stI）47.36%and stI/ltA 21.05%.The positive rate of virulence gene of EPEC were the bundle-formingpilus gene（bfpA）66.66%,eeeA gene 60.0%and eaeA/bfpA 26.67%.Two cases of E.coli septicemia was found in patients with gut the same clone.Conclusion：Intestinal pathogenic E.coli serotype caused a relatively small proportion of the clinical ExPEC,and mainly ETEC and EPEC serotypes.ExPEC in patients with septemia,especially in serious ill patients,its intestinal translocation of E.coli may be the source of ExPEC.

关 键 词：肠外感染大肠杆菌 血清型 毒力基因 脉冲场凝胶电泳 

分 类 号：R181.32[医药卫生—流行病学]