非O157产志贺毒素大肠埃希菌分离株血清型鉴定及主要毒力基因分析

目的 了解中国不同来源非O157产志贺毒素大肠埃希菌分离株血清型及主要毒力基因的流行情况。方法 采用O抗原基因簇特异性聚合酶链反应（PCR）结合全套O抗血清凝聚法确定O血清群，以PCR扩增和测序fliC基因确定H型；采用PCR方法对所有菌株进行stx1、stx2、eae及ehxA基因检测。结果 434株非O157 STEC分离株中，除不可分型菌株外，共检测出82种O血清群和28种H型，其中O20:H30、O2:H32和O2:H45为优势血清型。stx1、stx2和stx1+stx2 3种志贺毒素基因型的检出率分别为25.35%、64.98%和9.68%，而eae和ehxA基因的阳性率分别为3.92%和32.95%。仅15株菌同时携带3种毒力基因，且主要为血清型O26:H11的腹泻患者分离株。结论 我国非O157 STEC分离株血清型复杂多样，同时检测eae和ehxA基因对于发现高致病潜力的菌株具有重要参考价值。

Serotype and virulent gene profiles of non-O157 Shiga toxin-producing Escherichia coil isolates

Objective To understand the main virulent genes and serotypes of non-O157 Shiga toxin-producing Escherichia coli isolates collected in China.Methods The O serogroups were determined by O-antigen biosynthesis gene cluster PCR system combined with the complete O antisera agglutination test.H-antigen types were detected with PCR and sequencing of fliC.stx1,stx2,eae and ehxA genes were screened with PCR.Results Among 434 non-O157 STEC isolates,82 O serogroups and 28 H types were detected.O20∶ H30,O2∶H32 and O2∶H45 were the predominant serotypes.The positive rates of stx1,stx2,stx1 + stx2,eae and ehxA genes were 25.35％,64.98％,9.68％,3.92％ and 32.95％ respectively.Only 15 isolates harbored stx,eae and ehxA genes,which mainly derived from diarrheal patients.Conclusion The serotypes of nonO157 STEC isolates in China are diverse.Detection of eae and ehxA genes could be important for the detection of highly pathogenic strains.