我国2012－2015年门诊腹泻患者中致泻性大肠埃希菌流行特征分析

目的 了解我国门诊腹泻患者中致泻性大肠埃希菌（DEC）流行特征。方法 2012－2015年在27省（直辖市、自治区）170家医院门、急诊中开展腹泻病监测，收集腹泻病例的临床和流行病学资料，同时采集粪便标本，送往92家网络实验室开展DEC检测。结果 在46 721例腹泻监测病例中，DEC的总检出率为7.7%，且各地区检出率存在较大差异。在2 982例（6.4%）报告了PCR菌型鉴定分类信息的DEC阳性病例中，肠集聚性黏附大肠埃希菌（EAEC）是最主要的类型（1 205例，40.4%），其次是肠致病性大肠埃希菌（EPEC）（815例，27.3%）和肠产毒性大肠埃希菌（ETEC）（653例，21.9%）。整体分析，25～34岁青壮年、暖温带地区和黏液便的DEC检出率较高，检出率分别为10.1%、11.1%和9.4%。DEC的季节性发病特征明显，各菌型的流行高峰均在夏季。结论 DEC是我国腹泻病门诊重要病原体之一，流行菌型以EAEC、EPEC和ETEC为主，不同地区、不同年龄人群、不同季节的流行特征存在差异。

Epidemiological characteristics of diarrheagenic Escherichia coli among diarrhea outpatients in China, 2012-2015

Objective To understand the epidemiological characteristics of diarrheagenic Escherichia (E.) coli (DEC) among diarrhea outpatients in China. Methods Diarrhea surveillance program was conducted in outpatient and emergency departments from 170 hospitals that under the sentinel programs in 27 provinces, from 2012-2015. Clinical and epidemiological data regarding diarrhea patients were collected, with fecal specimens sampled and tested for DEC in 92 network-connected laboratories. Results Among all the 46 721 diarrhea cases, 7.7% of them appeared DEC positive in those with geographic heterogeneity. In 2 982 cases (6.4%) with available data on PCR subtypes of DEC, enteroaggregative E. coli (EAEC, 1 205 cases, 40.4%) appeared the most commonly seen pathogens, followed by enteropathogenic E. coli (EPEC, 815 cases, 27.3%), and enterotoxigenic E.coli (ETEC, 653 cases, 21.9%). The highest positive rate of DEC was observed in outpatients of 25-34 years old (10.1%), living in the warm temperate zones (11.1%), and with mucous-like stool (9.4%). The positive rate of DEC showed a strong seasonal pattern, with peaks in summer, for all the subtypes. Conclusions DEC seemed easy to be detected among diarrhea outpatients in China, with EAEC, EPEC and ETEC the most commonly identified subtypes. Epidemiological characteristics regarding the heterogeneities of DEC appeared different, in regions, age groups and seasons. Long-term surveillance programs should be strengthened to better understand the epidemiology of DEC, in China.