3起细菌性痢疾聚集性疫情实验室检测分析

Analysis of laboratory test of three clustering epidemics of bacterial dysentery

目的比较新疆伊犁哈萨克自治州(简称伊犁州)3起细菌性痢疾聚集性疫情实验室检测结果,优化检测程序,为今后及时、准确地开展现场调查和病原排查做好实验室技术储备。方法采用现场流行病学、环境卫生学调查与实验室检测相结合的方法,检测粪便、肛拭子样本、食品样本和生活饮用水样本,开展菌株分离、鉴定和卫生学评价。结果2012,2013和2018年伊犁州疾病预防控制中心实验室共接到3起突发群体性腹泻事件报告,142份人粪便样本中,检出宋内I相菌8株、福氏群7型18株,福氏群3型和4型2株;3起疫情粪便样本中均检出宋内I相菌,在SS和MAC分离鉴定培养基中占优势生长的大肠埃希菌3株;12份学校早餐样本中,检出宋内Ⅱ相菌1株;11份生活饮用水样,菌落总数、总大肠菌群和耐热大肠菌群均不同程度超标。结论3起聚集性疫情均因志贺菌污染水源或食物所致,检出优势菌宋内菌群(D群)基本与国家监测哨点结果一致;水体粪便指示菌的污染,一定程度反映了肠道致病菌的存在;造成志贺菌实验室误诊的关键因素,除经典的宋内菌迟缓发酵乳糖现象外,呈志贺样生化反应、不活泼大肠埃希菌的鉴别也很重要。

Objective To compare and analyze the laboratory test results of three clustering epidemics of bacterial dysentery in Ili Kazak autonomous prefecture,optimize the testing procedures,so as to prepare the laboratory technique reserve for timely and accurately carrying out the site investigation and identifying pathogen in the future.Methods The field epidemiology,environmental health survey and laboratory testing methods were carried out for the determination of samples of feces,anal swabs,food and drinking water,and conducted the isolation identification of bacteria strains and hygienic evaluation.Results There were 3 reports on cluster epidemics of diarrhea received by the laboratory of The Center for Disease Control and Prevention of Ili Prefecture in 2012,2013 and 2018.There were 8 strains of bacteria Sonomi phase I,18 strains of Fouli group 7,and 2 strains of Fouli group 3 and 4 were detected from the 142 feces of patients.The strains of bacteria Sonomi phase I were found in all feces among the 3 cluster epidemics,and there were 3 strains of Escherichia coli dominantly grew in the SS and MAC isolation medium.There was 1 strain of bacteria Sonomi phaseⅡdetected in 12 breakfast samples from school.The total number of bacteria colony,total coliform group and heat-resistant coliforms exceeded the standard to different degrees in 11 samples of drinking water.Conclusions The 3 cluster epidemics of bacterial dysentery are caused by Shigella contamination in food and drinking water.The detection for the dominant strains of Sonomi group(group D)are basically consistent with the results of the national monitoring point.The water contamination of feces indicator bacteria reflects the existence of intestinal pathogenic bacteria to certain degree.The key factors of misdiagnosis of Shigella at laboratory are the Shigella-like biochemical reaction and identification of inactive Escherichia coli,except the slow lactose fermentation by Sonomi bacteria.