To conduct outbreak identification and transmission factor analysis of typhoid epidemic occurred in Xinqiao town, Jiangyin city from June to September 2016. A total of 14 strains of Salmonella typhi isolated from confirmed cases were collected, and 65 external environment samples and 13 food samples related to the outbreak were taken. Real-time PCR was used to detect specific gene of Salmonella typhi in the samples. Conventional method was used to isolate strains. The strains isolated from both the samples and patients in the epidemic were subjected to antimicrobial susceptibility testing and PFGE molecular characteristics. Salmonella typhi strain was isolated from one external sample (well water of a deli processing plant). The results of drug susceptibility showed that 15 strains were resistant to nalidixic acid. A total of 15 strains of Salmonella typhi were divided into 2 molecular patterns by pulsed field gel electrophoresis. The fingerprints of PFGE from the 13 patients and the environmental isolate were completely consistent, and there was one band difference from the other patient isolate. Combined with the epidemiological investigation and laboratory test results, it was determined that the outbreak was caused by genetic clone of the same Salmonella typhi. Food processing plant should be one of the key links.
针对一起于2016年6—9月发生在江阴市新桥镇的伤寒疫情开展暴发确认和传播因素分析。首先收集分离自确诊病例的14株伤寒沙门菌；再采集与疫情相关的外环境样本65份和食品样本13份，运用实时荧光PCR法检测样本中伤寒沙门菌特异基因，采用常规分离培养法分离伤寒沙门菌。对所有伤寒沙门菌分离株进行药敏试验及脉冲场凝胶电泳（PFGE）分析。从外环境样本（K熟食店加工厂井水）中分离得到1株伤寒沙门菌。15株伤寒沙门菌均对萘啶酸耐药，经脉冲场凝胶电泳后共获得2种带型，其中13株病例分离株和环境分离株的PFGE指纹图谱完全一致，另外1株病例分离株的PFGE带型存在1个条带的差异。结合流行病学调查和实验室检测结果，判定本次暴发疫情是由同一伤寒沙门菌遗传克隆的传播而导致，食品加工厂应属于是传播环节之一。.
Keywords: Electrophoresis,gel,pulsed-field; Salmonella typhi; Tracing; Typhoid fever.