副溶血性弧菌引起的食物中毒调查及病原学研究

目的查明一起升学宴食物中毒的原因,确定致病菌,为食物中毒处置提供依据。方法开展现场流行病学调查,搜索病例,查找可疑中毒餐次及食物,采集病例及食物样本开展实验室检测,确定致病病原和毒力基因,并使用脉冲场凝胶电泳(PFGE)对分离株进行同源性鉴定。结果共搜索中毒病例92例,罹患率为46.94%,主要临床表现为腹泻(93.48%)、腹痛(86.96%)、恶心(39.13%)、呕吐(34.78%)和发热(17.39%),发病潜伏期中位数为17h。从3例患者样本(2份粪便、1份肛拭子)检出副溶血性弧菌,毒力基因trh阳性且PFGE图谱带型相似性系数为97.4%。10份食品样本中未能检测出致病菌。病例对照研究结果表明6种食物为可疑食物(OR值分别为15.75、10.14、8.44、5.93、5.56、4.71,P均<0.05且OR值95%CI>1),其中夫妻肺片、加州鲈鱼暴露的危险度极高(OR值>10)。结论升学宴就餐引起的食物中毒由trh阳性副溶血性弧菌引起,未能确定可疑食品(夫妻肺片和加州鲈鱼污染的可能性较大),建议加强对餐饮单位的监督管理及食品安全宣传教育工作,从源头上减少食源性疾病事件的发生。

Investigation on a food poisoning caused by Vibrio parahaemolyticus and its etiology

Objective To find out the causes of food poisoning in a school banquet and identify the pathogenic bacteria,so as to provide evidence for the treatment of food poisoning.Methods A field epidemiological survey was conducted to search for cases,find suspicious poisoning meals and food,and collect cases and food samples for laboratory testing,to determine pathogenic pathogens and virulence genes.The pulsed field gel electrophoresis(PFGE)was applied to identify the homology of the pathogens.Results A total of 92 poisoning cases were found,and the incidence rate was 46.94%.The main clinical manifestations were diarrhea(93.48%),abdominal pain(86.96%),nausea(39.13%),vomiting(34.78%)and fever(17.39%).The median of onset latency was 17 hours.Vibrio parahaemolyticus was detected in samples from 3 patients(2 stools and 1 anal swab).The virulence gene trh was positive and the similarity coefficient of PFGE banding was 97.4%.Pathogenic bacteria were not detected in 10 food samples.The results of the case-control study showed that six types of food were suspicious(OR values were 15.75,10.14,8.44,5.93,5.56 and 4.71 respectively,P<0.05 and OR 95%CI>1),including couple lung slices and California bass with extremely high risk of exposure(OR values>10).Conclusion The food poisoning resulted from this enrollment banquet was caused by trh-positive Vibrio parahaemolyticus and no suspicious food was identified(the possibility of contamination by couples'lung slices and California sea bass was high).It is suggested that the supervision and management of catering units and food safety publicity and education should be strengthened to reduce the occurrence of food-borne diseases from the source.