2022年北京市一起产气荚膜梭菌引起的食源性疾病暴发事件病原学分析

Etiological analysis on an outbreak of foodborne disease caused by Clostridium perfringens in Beijing,2022

目的 对一起北京市某学校由产气荚膜梭菌导致的腹泻暴发事件进行病原学分析,为类似疫情的快速精准分析与处置提供参考。方法 采用实时荧光聚合酶链式反应(PCR)方法对样本进行多重病原筛查;根据初筛结果进行常规细菌分离培养、生化鉴定和质谱分析;分离到的产气荚膜梭菌进行PCR毒力基因检测和脉冲场凝胶电泳分子分型。结果 28份病例肛拭子样本中有26份产气荚膜梭菌核酸初筛阳性,分离菌株26株;13份粪便样本有10份产气荚膜梭菌核酸初筛阳性,4份样本分离到20株产气荚膜梭菌;其他样本未检测到病原;46株菌均携带cpa基因和cpe基因,为携带肠毒素CPE基因的A型产气荚膜梭菌;46株菌中41株菌集中在2个脉冲场凝胶电泳带型。结论 本次腹泻暴发事件由产气荚膜梭菌(含肠毒素)导致,分子生物学方法可用于产气荚膜梭菌暴发事件的快速检测。

Objective To povide a reference for rapid and accurate analysis of similar epidemics through pathogenic analysis of an outbreak of diarrhea caused by Clostridium perfringens in a school in Beijing.Methods Multiplex real-time polymerase chain reaction(PCR)was used for screening of molecular pathogens.Based on the preliminary screening results,routine bacterial isolation and culture,biochemical identification and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry(MALDI-TOF MS)analysis were conducted.Virulence gene detection and pulsed field gel electrophoresis(PFGE)molecular typing were performed on the isolated C.perfringens.Results Among the 28 anal swab samples,26 samples were positive for C.perfringens in preliminary screening,and 26 strains were isolated.In 13 fecal samples,10 samples were positive for C.perfringens in preliminary screening,and 20 strains were isolated from 4 samples.No pathogens were detected in other samples.The 46 strains of C.perfringens all carried cpa and cpe genes,which were C.perfringens type A with enterotoxin CPE gene.Among the 46 strains,41 strains are concentrated in 2 PFGE bands.Conclusion This diarrhea outbreak was caused by Clostridium perfringens(with enterotoxin),and molecular biological methods can be used for rapid detection of C.perfringens outbreaks.