某杂技班食堂1起食物中毒流行病学分析

Epidemiological Investigation on Food Poisoning Occurred in Refectory for Acrobatic Training Class

目的查明中毒事件发生原因和环节,提出针对性防控措施和建议。方法采用回顾性队列研究、进行食品卫生学调查和实验室检测分析危险食物。结果本次事件共有18例病例,罹患率为82%。主要临床症状为呕吐(100%),恶心(94%),腹痛(44%)和腹泻(17%)。流行曲线形态表现为快速上升,快速下降,高峰持续时间短,提示为点源暴露。未发现有统计学意义的暴露食物。蛋炒饭为所有调查对象的共同食物,比较不同的蛋炒饭进食量(按体重调整)引起的呕吐次数,发现≥2碗/100 kg.bw组平均呕吐次数3.7次明显高于1碗/100 kg.bw组(平均呕吐次数1.0次),差异有统计学意义(t=2.3,P<0.05)。同时对蛋炒饭进食量(按体重调整)与引起的呕吐次数作spearman相关分析,相关系数r s=0.472(P<0.05),提示进食炒饭的量与呕吐次数存在剂量反应关系。蛋炒饭所使用的米饭有1/3来自上一餐次的剩饭(该剩饭在22℃下放置了4 h)。剩余蛋炒饭和患者呕吐物的蜡样芽孢杆菌和金黄色葡萄球菌检测为阴性。结论这起事件很可能由剩余米饭不当存放所致,其致病因子可能是腊样芽孢杆菌呕吐毒素。

Objective To identify the cause of the food poisoning incident in a refectory for acrobatic training class and its risk factors for further pertinent prevention measures. Methods The food-specific attack rates（ AR） were compared in a retrospective cohort study and leftover fried rice and vomitus specimen were collected for staphylococcus aureus and bacillus cereus test. Results The AR was 82%（ 18 /22）; the main clinical symptoms were vomiting（ 100%）,nausea（ 94%）,abdominal pain（ 44%） and diarrhea（ 17%）. The mean vomiting times among students who ate one bowl of fried rice was 3. 7 compared to 1 among students who ate ≧ 2 bowls（ t = 2. 3,P0. 05）. There was a dose-response relationship between the numbers of bowls of fried rice consumed per 100kg weight and vomiting times（ Spearman correlation coefficient = 0. 47,P 0. 05）. The leftover rice in lunch was kept at room temperature（ 22℃） for 4 hours. Then it was fried with egg and served for dinner. The staphylococcus aureus and bacillus cereus test were negative. Conclusion The outbreak is caused probably by the fried rice. Vomitoxin of bacillus cereus is likely a contributing causative agent.