关键词: 大肠埃希菌O157∶H7, 特异性基因, 毒力基因

Abstract: Objective:To detect specific genes of O157 O antigen and H7 antigen of the isolates which had been identified as E.colistrain with serum slide agglutination assay in Jiangsu province in 2000-2001.To understand the virulent gene carrying rate and the virulent gene footprint of E.coli O157 strain isolated from surveillance spots in 2000.Methods:Polymerase chain reaction was used to identify specific O157 gene and H7 gene.Multi-primer PCR was used to detect and analyze virulent genes of VT1,VT2,eaeA,hly etc.Results:134 strains were primarily identified as E.coli O157∶H7 with serum slide agglutination assay,by specific gene detection,72.4%(93/134) was confirmed as E.coliO157,only 29.1%(39/134) was E.coliO157∶H7,26.9%(36/134) was not E.coliO157∶H7 and 44.3%(58/134) O157 strain without flagellae H7 antigen.Detecting the strains isolated from host animals in 2000 with specific gene identification,the rates of those with virulent gene in non- E.coli O157,E.coli O157∶H、and E.coliO157∶H7 were 0%(0/18),10.7%(3/28) and 93.1%(27/29) respectively.The main type was VT2+eaeA+hly.Conclusion: E.coli O157∶H7 specific gene detection can reduce greatly the misdiagnosis with serum slide agglutination assay.The change of virulent gene type can be analyzed by combing with virulent gene detection.This is very important for making effective measures to control the epidemic of E.coliO157∶H7.