一起鼠伤寒沙门菌引起食源性暴发事件的药敏及同源性分析

Drug sensitivity test and homological analysis of a foodborne disease outbreak caused by Salmonella typhimurium

目的对一起食源性暴发事件的病原菌鼠伤寒沙门菌进行药敏实验和同源性分析,为临床治疗、事件溯源及防控提供科学依据,探讨基质辅助激光解析电离飞行时间质谱(MALDI-TOF MS)技术在沙门菌同源分析中的应用可行性。方法对该事件11株鼠伤寒沙门菌进行15种抗生素药敏实验,运用脉冲场凝胶电泳(PFGE)技术、MALDI-TOF MS技术分别在分子分型和蛋白质分型方面对菌株进行同源性分析。结果药敏结果一致,均对左氧氟沙星处于中介,对头孢呋辛酯、头孢西丁、阿米卡星、头孢呋辛钠耐药。PFGE、MALDI-TOF MS分型后的聚类相似度分别为100%、>80%,均提示属于同一亚型,来源于同一克隆。结论临床治疗应按照药敏结果,正确规范使用抗生素;同源性分析得出该事件是由被鼠伤寒沙门菌污染的鸡蛋干引起;MALDI-TOF MS技术可以便捷地应用于沙门菌快速同源性分析。

Objective To conduct drug sensitivity test and homological analysis of a foodborne disease outbreak caused by Salmonella typhimurium,so as to provide scientific basis for clinical treatment,traceability,prevention and control.Besides,this study explored the feasibility of the application of Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry technology(MALDI-TOF MS)in the homological analysis ofSalmonella.Methods Fifteen antibiotic susceptibility tests were performed on 11 strains ofSalmonella typhimurium.The homological analysis was performed by pulsed field gel electrophoresis(PFGE)and MALDI-TOF MS in molecular typing and protein typing,respectively.Results The drug sensitivity results were consistent.All of them were intermediate to Levofloxacin and resistant to Cefuroxime axil,Cefoxitin,Amikacin and Cefuroxime sodium.The clustering similarity of PFGE and MALDI-TOF MS typing was 100%and greater than 80%,respectively.It indicated that they belonged to the same subtype and came from the same clone.Conclusion In clinical treatment,antibiotics should be used correctly according to the results of drug sensitivity.Homological analysis showed that the incident was caused by dried eggs contaminated withSalmonella typhimurium.MALDI-TOF MS can be easily applied to rapid homological analysis ofSalmonella.