浙江省腹泻患者致泻性大肠埃希菌血清型分布及其鉴定效率的评价

Studies on the serum types and identification efficiency on Diarrheagenic Escherichia coli isolated from diarrhea patients, in Zhejiang province

目的 了解浙江省致泻性大肠埃希菌（DEC）血清型分布并探讨其血清学鉴定分类方法的鉴定效率。方法 对2009年7月至2013年6月浙江省腹泻症候群病原谱监测网络菌株库中的696株DEC菌株（通过毒力基因鉴定）开展血清学凝集试验，比较毒力基因和血清学鉴定分类的结果。结果 696株DEC中288株（41.4%）能明确O抗原型别，分属于35种O血清群。171株（24.6%）H血清凝集，分属于21种H型。肠集聚性大肠埃希菌（EAEC）、产肠毒素性大肠埃希菌（ETEC）、肠致病性大肠埃希菌（EPEC）和肠出血性大肠埃希菌（EHEC）凝集率分别为31.9%（130/408）、70.6%（127/180）、31.5%（29/92）和14.3%（2/14），分属于30、18和15种O血清群，1株EHEC为O157∶H7。EAEC和EPEC血清群相对较多样化，而ETEC则相对集中，不同类型DEC可具有同一血清群/型。根据血清学结果可分类的75株DEC中，42株毒力基因和血清学分类结果一致，33株不一致。结论 浙江省DEC血清群/型种类多样，单纯采用血清学筛查可造成极大的漏检或误分，建议采用毒力基因鉴定分类。

Objective To investigate the serotypes of Diarrheagenic Escherichia coli （DEC） isolated from diarrheal patients in Zhejiang province and to explore the identification efficiency of serological screening methods. Methods Serological agglutination tests were carried out in 696 strains of DEC （through the identification of virulence genes） which were selected from the Infectious Diarrhea Pathogen Monitoring Network Strain Bank of Zhejiang province, from July 2009 to June 2013. Results of virulence genes, serological identification and classification were compared. Results Among the 696 isolates of DEC, O antigen type was identified in 288 （41.4%） isolates which belonging to 35 different ‘O’ serum types. H antigen was seen in 171 （24.6%） isolates and determined as having 21 types. The agglutination rates of EAEC, ETEC, EPEC and EHEC isolates were 31.9% （130/408）, 70.6% （127/180）, 31.5% （29/92） and 14.3% （2/14）, respectively and belonged to 30, 18, 15 kinds of ‘O’ sero-groups, respectively. One EHEC isolate was identified as O157：H7. Serum groups were diverse for EAEC and EPEC, while relatively concentrated on ETEC. Different types of DEC might belong to the same sero-group or type. Among the 74 strains of DEC available for classification serologically, 41 isolates were in consistent with virulence gene identification and another 33 strains were not. Conclusions The sero-group/type of DEC strains in Zhejiang were varied. Based on the serological screening method alone, DEC classification might end in getting the wrong answer, thus we would recommend the use of virulence gene for the purpose of identification.