一起基于国家致病菌识别网的志贺菌病暴发事件实验室分析

Laboratory analysis on a Shigellosis outbreak based on PulseNet China

目的对基于国家致病菌识别网监测体系的志贺菌病暴发事件进行实验室分析。方法对2019年北京市通州区志贺菌病暴发疫情菌株进行分离和鉴定,结合2015—2019年北京市通州区监测和暴发疫情菌株进行脉冲场凝胶电泳分子分型和药敏试验比对分析。结果28株志贺菌中27株带型相似度≥92.0%,疫情相关菌株带型相似度≥97.1%,说明本地区存在一组亲缘关系接近的志贺菌并以低流行态势存在。所有菌株均为多重耐药菌,2019年宋内志贺菌分离株对庆大霉素耐药与2015—2018年比较差异有统计学意义(χ2=49.907,P<0.001),提示庆大霉素在志贺菌病治疗中应慎重使用。全部菌株对环丙沙星、氯霉素、头孢西丁和亚胺培南均敏感,提示该类药物对志贺菌感染具有较好的治疗效果。结论近年来,通州区流行的痢疾菌株主要为宋内志贺菌,菌株同源性较高,多重耐药情况严重,应利用国家致病菌识别网监测体系加强志贺菌的日常监测和耐药监测。

Objective To conduct a laboratory analysis on a Shigellosis outbreaks in Tongzhou district of Beijing in September,2019 based on PulseNet China.Methods Isolation and identification of the Shigellosis outbreak strains were conducted in Tongzhou district of Beijing in 2019,pulsed field gel electrophoresis(PFGE)molecular typing and drug resistance test were carried out and compared based on the Shigella strains isolated from surveillance and outbreaks in Tongzhou during 2015–2019.Results Among the 28 Shigella strains,the similarity of the band patterns of 27 strains was≥92.0%,and the similarity of the band patterns of outbreak related strains was≥97.1%,indicating the existence of a group of closely related Shigella strains in this area with limited circulation.All the strains were multi-drug resistant.Compared with the Shigella sonnei isolates from 2015 to 2018,the difference in resistance to gentamicin of the isolates in 2019 was significant(χ2=49.907,P<0.001),suggesting that gentamicin should be used with caution in the treatment of Shigellosis.All the strains were sensitive to ciprofloxacin,chloramphenicol,cefoxitin and imipenem,suggesting that these antibiotics have good therapeutic effects on Shigella infection.Conclusion In recent years,Shigella sonnei is the main pathogen of dysentery in Tongzhou,the strains share high homology and have severe multi-drug resistance.Therefore,it is necessary to make use of national network surveillance system for pathogen identification to strengthen the routine and drug resistance surveillance for Shigella.