一起由金黄色葡萄球菌所致学校食物中毒调查分析

目的 查明一起学校食物中毒发生的原因和可疑危险因素,提出有效控制措施防止事态蔓延,为类似食源性疾病的调查和预防提供参考。方法 利用现场流行病学、食品卫生学和实验室检测等方法,开展病例主动搜索、个案调查和现场卫生学调查,采集食品、外环境和病例的标本进行实验室检测,以判断本次事件的可疑餐次和食物。结果 通过开展主动搜索,共搜索到21例病例(疑似19例,确诊2例),学生罹患率为12.96%(21/162)。临床症状主要是呕吐(95.24%, 20/21)、腹痛(66.67%, 14/21)、恶心(66.67%, 14/21)、腹泻(57.14%, 12/21)。病例对照研究显示,可疑食物为10月16日晚餐的剩米饭(OR=18.18,95%CI: 2.05～161.38)。在1例病例的肛拭子和另外1例病例的呕吐物中分离出金黄色葡萄球菌和B型肠毒素。结论 本次食物中毒事件是由金黄色葡萄球菌产生B型肠毒素所致,可疑食物为10月16日晚餐中食堂提供的剩米饭。米饭在常温下放置5 h左右且食用前未彻底加热是本次事件发生的危险因素。学校食堂存在食品卫生安全隐患,应进一步加强对学校食堂的食品安全监管和从业人员的食品安全教育,提高食品安全意识,预防类似事件的发生。

Investigation and analysis of a Staphylococcus aureus food poisoning incident in a school

Objective To identify the causes and suspected risk factors of the food poisoning incident, provide evidence for control measures, and provide reference for the investigation and prevention of similar food poisoning. Methods The case investigations and on-site hygiene surveys were carried out by actively searching for cases through epidemiological and laboratory testing techniques. Then, the relevant food, external environment and case samples were collected for laboratory testing to determine the suspicious meals and food of this event. Results A total of 21 cases(including 2 confirmed cases) were screened out. The attack rate of this event was 12.96%(21/162), and the main clinical symptoms were vomiting (95.24%,20/21), abdominal pain (66.67%,14/21), nausea (66.67%,14/21) and diarrhea (57.14%,12/21). Data from the case control studies result showed that the suspected food was the rice left over from the dinner on October 16th (OR=18.18,95%CI: 2.05-161.38). Two cases were detected Staphylococcus aureus and enterotoxin type B in an anal swab and vomit. Conclusion The cause of this food poisoning outbreak was the leftover rice from the canteen on the 16th dinner, which was contaminated by Staphylococcus aureus and enterotoxin type B. Rice was placed at room temperature for about 5 hours and was not heated thoroughly before eating, which was a risk factor for this event. Food safety supervision and food safety education for canteen employees should be further strengthened to improve food safety awareness and prevent similar incidents.