四川省2005年霍乱分子流行病学特征

目的：分析四川省2005年霍乱弧菌分子特征,以及霍乱暴发疫情分离的菌株与菌株之间,疫情分离的菌株与海、水产品监测分离的霍乱弧菌之间的遗传相关性,查找霍乱传染来源,为预测疫情和制定防治措施提供依据.方法：利用聚合酶链反应（PCR）检测O139群霍乱弧菌特异性编码脂多糖基因（LPS）和霍乱毒力基因（ctxAB）;脉冲场凝胶电泳对菌株进行分子分型,所得结果以BioNumerics V4.0软件UPGMA方法进行聚类分析.结果：所试16株霍乱弧菌14株LPS阳性,为O139群霍乱弧菌;另2株为O1群稻叶型霍乱弧菌.2株稻叶型霍乱弧菌和1株O139群霍乱弧菌ctxAB阴性,其余13株菌均具有ctxAB,为产毒株.对16株菌以NotⅠ酶切后PFGE可分为5个型别.O139群霍乱弧菌优势流行株与从甲鱼分离的O139群霍乱弧菌PFGE型别一致,且同为产毒株.结论：甲鱼等海、水产品被O139群霍乱弧菌污染情况严重,甲鱼中分离的O139群霍乱弧菌与霍乱疫情分离菌株之间高度同源,被污染的甲鱼可能是本年度食源性霍乱暴发的主要传染来源之一,海、水产品的监测是近期霍乱防控的重点.

MOLECULAR EPIDEMIC CHARACTERISTICS OF CHOLERA OF SICHUAN PROVINCE IN 2005

Objective:To study the characteristics of molecular typing of cholera strains collected in Sichuan Province in 2005,to analysis the phylogenic relationship among the strains isolated during cholera outbreaks,the strains isolated from sea food samples and strains from outbreaks,to trace the source of cholera infection,so as to support the policy-making on cholera control.Methods:O139 specific gene and cholera toxin gene were detected by PCR.PFGE was used for subtyping isolates.Clustering of patterns was analysed with software BioNumerics.Results:In all the analysed 16 strains,14 were Vibrio cholera serogroup O139 because of positive results in LPS PCR test.The other two were O1 Inaba.Only the two O1 Inaba and one of O139 were toxigenic negative,all other 13 O139 were toxigenic.All 16 strains were clustered into 5 PFGE patterns when digested with Not I.the patterns of toxigenic O139 strains isolated from turtles in the markets were identical with the patterns of epidemic strains in the same period.Conclusion:Sea foods such as turtle are seriously contaminated by cholera.Strains from turtle are highly homology with epidemic strains,which points out turtle might be one of the major sources of outbreaks.Sea food surveillance is one of important parts of cholera control strategy.