一起疑似产气荚膜梭菌食物中毒事件的实验室检测分析

Laboratory analysis of a suspected food poisoning incident caused by Clostridium perfringens

目的 通过一起疑似产气荚膜梭菌食物中毒事件的检测分析,为类似食物中毒事件提供诊断依据。方法 采用多重实时荧光定量PCR方法和基因芯片检验方法快速筛查识别病原菌,根据初筛结果进行常规的细菌分离培养、生化鉴定和质谱分析,对分离到的菌株采用脉冲场凝胶电泳(PFGE)技术进行分子分型,采用BioNumerics 8.0软件对菌株的PFGE指纹图谱进行聚类分析。结果 多重实时荧光定量PCR方法提示4份粪便标本中均有产气荚膜梭菌和基因芯片检验方法提示1份鸡肝食品中有产气荚膜梭菌,并通过常规的细菌分离培养、生化鉴定和质谱分析从2份剩余鸡肝和4份腹泻患者粪便中分离到产气荚膜梭菌,其中只有3份粪便标本中产气荚膜梭菌计数>1.0×10~6 CFU/g,但通过PFGE聚类分析从6份标本中检出的菌株图谱完全一致。结论 通过从食物和腹泻标本中检出PFGE图谱相似度100%的产气荚膜梭菌,说明此次食物中毒可能是由被产气荚膜梭菌污染的鸡肝导致的,今后要提高由厌氧菌引起的食物中毒的认识水平,防止漏检。

Objective To provide a diagnostic basis for similar food poisoning incident through analysis of the detection of a suspected Clostridium perfringens food poisoning event. Methods Multiplex real-time quantitative PCR and Gene microarray detection were used for rapid screening and identification of pathogenic bacteria. Based on the results of the initial screening,routine bacterial isolation and culture, biochemical identification and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry(MALDI-TOF MS) analysis were performed Molecular typing of the isolated strains was performed by pulsed field gel electrophoresis(PFGE) technique.The PFGE fingerprint profiles of these stains were clustered and analyzed by using BioNumerics 8.0 software. Results C.perfringens was detected in all 4 fecal specimens by Multiplex real-time quantitative PCR and 1 food sample of chicken liver by gene microarray.The bacteria were isolated and identified from 2 chicken liver samples and 4 feces specimens by routine bacterial culture, biochemical identification and mass spectrometry. MALDI-TOF MS. Only 3 of these 4 feces specimens had C. perfringens counts>1.0×106 CFU/g, However, the strains profiles detected from the six specimens by PFGE clustering analysis. were completely consistent Conclusion C. perfringens from food and diarrhea samples showed 100% consistent in PFGE pattern, indicating that the food poisoning may be caused by chicken liver contaminated by C. perfringens And the awareness of food poisoning caused by anaerobic bacteria should be improved to prevent missing detection in the future.