同一肇事地不同餐次食物中毒现场流行病学调查及肠毒素基因鉴定

目的查明本次食物中毒发生的原因,确认致病危害因素及其来源,控制暴发的扩散和蔓延。方法采用现场流行病学调查方法,开展病例搜索和个案调查,并采集相关样本进行实验室检测及肠毒素基因鉴定。运用流行病学曲线推算潜伏期范围,确定中毒餐次和中毒食品。结果共搜索确诊中毒病例27例,主要临床特征为恶心、呕吐、腹泻,部分病例伴腹痛、头痛、头晕等。中毒餐次为2014年12月10日的午餐和晚餐,中毒食品为烤肉拌饭,致病因子为金黄色葡萄球菌A型肠毒素。烤肉中分离的金黄色葡萄球菌菌株间PFGE图谱相似度100%,具有同源性;RT-PCR鉴定毒素基因为A型肠毒素。结论发生在同一肇事地不同餐次由金黄色葡萄球菌A型肠毒素引起的食物中毒,交叉污染是金黄色葡萄球菌污染来源最重要的传播方式,应加强餐饮行业监管和关键环节控制,防止类似事件的再次发生。

Field epidemiological investigation and enterotoxin gene identification of food poisoning caused by different meal times from the same accident unit

To find out the cause of a food poisoning event, identify the source of infection and risk factors and to control the spread of outbreak.Methods Case research and investigation were carried out adopting the method of field epidemiological investigation. Samples were collected for laboratory test and enterotoxin gene identification. Incubation period was calculated by epidemiological curves to identify the poisoning meal time and food. Results Nausea, vomiting and diarrhea occurred predominantly in 27 confirmed poisoning cases, accompanied by abdominal pain, headache and dizziness in some cases. The poisoning meal time was lunch and supper in December 10^th, and the poisoning food was barbecue rice. The cause of the disease was Staphylococcus aureus enterotoxin A. The similarity of PFGE pattern between strains of Staphylococcus aureus was 100%, sharing high homology. Toxin genes were confirmed as enterotoxin A by RT-PCR.Conclusion The food poisoning occurring in the same place at different meal times was caused by Staphylococcus aureus enterotoxin A. Cross contamination was the most important factor of transmission of Staphylococcus aureus. Supervision should be strengthened in critical control point for restaurants to avoid recurrence of similar incidents.