2010-2015年深圳市龙岗区肠产毒性大肠埃希菌感染的流行特征及脉冲场凝胶电泳分子分型

目的 了解广东省深圳市龙岗区腹泻患者中产毒性大肠埃希菌（ETEC）的流行状况及菌株的分子特征。方法 对2010-2015年来自深圳市龙岗区散发腹泻病例的1204份粪便标本进行ETEC分离培养、生化、血清分群及PCR毒力基因（estIa、estIb、elt）鉴定，并采用脉冲场凝胶电泳（PFGE）技术对阳性菌株进行分子分型。结果 腹泻人群中ETEC的阳性率为5.8%；年龄分布上检出率差异有统计学意义，以19~25岁成年人感染多见；季节分布上检出率差异无统计学意义。70株ETEC共检出14种血清型，以O159和O148多见，分别占25.7%和18.6%；携带毒力基因以estIb为主，占65.7%。PFGE共分为60个型别，共存在10个克隆群组，C、G为地区内的优势克隆株。结论 2010-2015年深圳市龙岗区腹泻患者中ETEC的检出率较稳定，流行具有年龄分布特征，感染呈高度散发状态，但存在优势克隆菌株的感染流行。

Epidemiological characteristics and PFGE molecular typing of Enterotoxigenic E.coli in Longgang district,Shenzhen,2010-2015

Objective To study the epidemiological and molecular characteristic of Enterotoxigenic E.coli in diarrhea patients. Methods A total of 1204 stool samples were collected from patients with infectious diarrhea at Longgang district from 2010 to 2015. Enterotoxigenic E.coli strains were isolated and identified by biochemical identification and serotyping. Then detection of virulence genes was conducted with polymerase chain reaction(PCR). The molecular typing of the positive isolates was determined by using Pulsed-field gel electrophoresis. Results The positive rate of Enterotoxigenic E.coli in diarrhea patients was 5.8%. There were significant differences in the detection rate among different age groups, and the patients were mainly adults aged 19-25 years.There were no significant season specific differences in the detection rate. The fourteen serotypes were detected in all the isolates, and the serotype of O159 and O148 were predominant, accounting for 25.7% and 18.6% respectively. The estIb was the predominant virulence genes, accounting for 65.7%. Sixty XbaⅠ-pulsed field gel electrophoresis patterns (PTs)were identified.Ten main clone groups were identified at a 90% similarity. Among them, C and G were predominant. Conclusion The detection rate of Enterotoxigenic E.coli in diarrhea patients was stable from 2010 to 2015. The age distributionof Enterotoxigenic E.coli infection was obvious and the infection mainly occurred sporadically, but some predominant clone strains existed.