一起多型别副溶血性弧菌引起农村喜宴食物中毒的溯源分析

Traceability analysis on a case of food poisoning caused by multiple serotypes of Vibrio parahaemolyticus

目的通过对腹泻患者肛拭子标本和外环境样品的病原菌检测,利用脉冲场凝胶电泳(PFGE)分子分型技术对一起多型别副溶血性弧菌引起农村喜宴食物中毒原因开展溯源分析。方法对采集的共20份肛拭子标本和外环境样品进行病原学检测,并对检出的副溶血性弧菌进行血清分型、PFGE分型及tdh、trh、tlh、toxR基因检测。结果 20份样品/标本中15份检出副溶血性弧菌,11株为tdh+trh-tlh+toxR+基因型,4株为tdh-trh-tlh+toxR+基因型。其中12份患者肛拭子标本中有9份检出副溶血性弧菌,7份为O3∶K6血清型,2份为O2群;3份墩板涂抹样品中有2份检出O3∶K6血清型,1份为O1群;3份剩余食物样品中有2份检出副溶血性弧菌,分别为O1群和O10群;厨师肛拭子标本检出O11群副溶血性弧菌;PFGE聚类分析显示7份患者肛拭子标本和2份墩板涂抹样品中的O3∶K6型副溶血性弧菌带型高度同源,剩余食物来源的副溶血性弧菌核酸降解未能显示PFGE条带。结论本次事件是可疑食物交叉污染切菜墩板引起的以O3∶K6血清型为主的多种血清型别副溶血性弧菌的食物中毒。

Objective To investigate the source of a food poisoning case in a rural wedding banquet based on the PFGE analysis of the pathogenic bacterium isolated from the patient anal swabs and polluted external environment samples.Methods Etiological examinations of 20 specimens were performed. Serological typing,pulsed-field gel electrophoresis（ PFGE） analysis and tdh,trh,tlh,toxR genes test were carried out on the Vibrio parahaemolyticus（ VP） detected.Results Fifteen strains of VP were isolated from 20 samples. Gene tests showed that 11 specimens were tdh,tlh,toxR genes positive,while 4 were tlh,toxR genes positive. Nine out of 12 patient anal swab samples were VP positive,of which7 were O3 ∶ K6 serotype,while the remaining were O2 group; All 3 chopping block daub samples were VP positive,of which 2 were O3 ∶ K6 serotype,the third one was O1 group; 2 out of 3 remaining foods were VP positive,which were O1,O10 group respectively. The anal swab sample of the chef was O11 group positive. PFGE analysis revealed that the O3 ∶ K6 of the patient anal swabs and chopping block daub samples were highly homologous. Conclusion This was a food poisoning outbreak caused by multiple serotypes of VP mainly by O3 ∶ K6,which might be contaminated through chopping block.