2020年广西壮族自治区玉林市一起学校肠炎沙门菌感染事件暴发调查

Investigation of an outbreak of Salmonella enteritidis infection in a school in Yulin,Guangxi Zhuang Autonomous Region,2020

目的调查2020年广西壮族自治区玉林市一起学校不明原因引起的腹泻暴发事件,明确致病因子和感染来源,为预防类似事件的发生提供防控措施和建议。方法制定病例定义,开展病例搜索,对病例进行个案调查,开展食品卫生学调查,采集样本进行实验室检测,通过病原菌分离鉴定、分离菌株的脉冲场凝胶电泳(PFGE)和基因组测序技术,进行菌株同源性分析,并开展回顾性队列研究验证危险因素,采用SPSS 19.0软件进行统计分析。结果共搜索到病例28例(学生26例,学生家属2例),临床症状主要为发热(96.43%)、腹泻(78.57%)、腹痛(60.71%)、呕吐(35.71%)等,平均潜伏期15 h,食品卫生学调查发现2名无健康证的工作人员从事蛋清分离后临时参与了成品三明治的包装。回顾性队列研究结果显示进食三明治和未进食三明治者,感染病例罹患率差异具有统计学意义(相对危险度=32.27,95%置信区间:4.34~239.94)。采集病例生物标本中的14份肛拭子标本、2份血液标本以及1份食品标本均检出肠炎沙门菌,合计检出17株;PFGE和基因组测序的分析结果均显示17株菌株高度同源。结论该事件是由制作三明治过程中交叉污染,而引起的学校肠炎沙门菌食源性疾病暴发,建议监管部门加强对学校、食品生产企业的监督管理,防范此类事件发生。

Objective To understand the pathogenic factors and sources of infection of an outbreak of unexplained diarrhea in a school in Yulin,Guangxi Zhuang Autonomous Region in 2020,and provide suggestions for the prevention and control of such epidemic.Methods Based on the case definition developed,case finding,case investigation and food hygiene investigation were carried out,and samples were collected for laboratory testing,pathogen isolation and identification.Pulse field gel electrophoresis(PFGE)and genome sequencing technology were used for strain homology analysis,and a retrospective cohort study was conducted to identify risk factors.Software SPSS19.0 was used for statistical analysis.Results A total of 28 diarrhea cases were found,in whom 26 were students and 2 were family members of the students.The main clinical symptoms were fever(96.43%),diarrhea(78.57%),abdominal pain(60.71%),vomiting(35.71%).The average incubation period was 15 hours.Food hygiene investigation found that 2 workers without health certificates joined in the packaging of finished sandwiches after finishing egg white separation.The retrospective cohort study showed a significant difference in attack rate between sandwich eaters and non-sandwich eaters(RR=32.27,95%CI:4.34–239.94).14 anal swab specimens,2 blood specimens,and 1 food specimen were collected from the biological specimens of the case,and a total of 17 strains of Salmonella enteritis were detected;The results of PFGE and genome sequencing showed that the 17 strains were highly homologous.Conclusion This foodborne diarrhea outbreak was caused by cross contamination of S.enteritis in the sandwich preparation process.It is suggested to strengthen the food hygiene supervision and management in schools and food production enterprises to prevent foodborne diseases.