大肠埃希菌O157∶H7特异基因检测与毒力基因分析

Detection of Specific Gene and Analysis of Virulent Gene of E. coli O157∶H7

目的 :对江苏省 2 0 0 0和 2 0 0 1年分离的经血清玻片凝集试验初筛为大肠埃希菌O15 7∶H7(E .coliO15 7∶H7)的菌株进行O15 7O抗原及H 7抗原特异性基因检测 ,了解 2 0 0 0年监测点宿主动物分离O15 7菌株毒力基因携带率及毒力基因图谱。方法 :用聚合酶链反应法检测O15 7特异基因、H 7特异基因 ,多重引物聚合酶链反应法检测VT1、VT2、eaeA、hly等毒力基因并进行分析。结果 :13 4株血清玻片凝集试验初筛为E .coliO15 7∶H7的菌株经特异基因检测确定为E .coliO15 7的占 72 .4% (97 13 4) ,E .coliO15 7∶H 7的仅为 2 9.1% (3 9 13 4) ;非O15 7菌株占 2 6.9% (3 6 13 4) ,有44 .3 % (5 8 13 4)的O15 7菌株鞭毛抗原不是H7。 2 0 0 0年宿主动物分离菌株 ,经特异基因检测为非O15 7的不携带毒力基因 (0 18) ;为E .coliO15 7∶H ?的菌株 ,毒力基因携带率为 10 .7% (3 2 8) ;确定为E .coliO15 7∶H 7的菌株 ,毒力基因携带率高达 93 .1% (2 7 2 9) ,且毒力基因型以VT2 +eaeA +hly为主。 结论 :特异性基因检测鉴定E .coliO15 7∶H7,可大大减少血清玻片凝集试验的误判 ,结合毒力基因检测 ,可分析E .coliO15 7∶H 7菌株毒力基因型的变化 ,对制定切实有效的防制对策控制E .coliO15

Objective: To detect specific genes of O157 O antigen and H7 antigen of the isolates which had been identified as E.coli strain 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.coli O157,only 29.1%(39/134) was E.coli O157∶H7,26.9%(36/134) was not E.coli O157∶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.coli O157∶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.coli O157∶H7.