志贺菌痢暴发菌株的分子流行病学分析

目的 探讨4种基因分型方法在一起F2a志贺菌痢暴发的流行病学研究中的意义。方法 对43株从患粪便和食物中分离菌株进行质粒图谱分析、质粒DNA酶切图谱分析、随机PCR分析、setl／set2毒力基因PCR分析。结果 随机PCR将43株F2a志贺菌分为2个不同的谱型，质粒图谱、setl／set2毒力基因PCR分为3个不同的谱型。而质粒：DNA酶切图谱分为4个不同的谱型。其中基因型完全相同的菌株35株，为引起本次菌痢暴发的流行株。7株基因型不同的菌株是本次暴发期间同时存在的散发病例。从食物中分离的菌株基因型与流行株相同，证明此次暴发是通过污染的食物而引起传播的。食堂炊事员粪便中虽然分离出了F2a志贺菌，但基因型与流行株不同，不是本次暴发的传染源。结论 DNA水平上的分型方法能更为准确、深入地揭示菌痢暴发过程中各分离株之间的流行病学联系。

Molecular epidemiological analysis on shigellosis outbreak isolates

Objective To investigate the significance of four genety pe methods which were implicated in the molecular epidemiology study of a Shigel losis outbreak.Methods Plasmid profile analysis,Plasmid DNA restriction endonuclease analysis,RAPD-PCR,Set1/set2-PCR.Results The 43 isolates were subtyped to two genetypes wi th RAPD-PCR.They were subtyped to three genetypes with plasmid profile analysis and set1/set2-PCR,and subtyped to four genetypes with plasmid DNA restriction en donuclease analysis.35 of all isolates had same genetype.They were the epidemic strain in this outbreak.7 of all isolates had different genetypes.They were the sporadic strains which were isolated in the same time of the outbreak.The strain isolated from food had same genetype as epidemic strain.It proved that the rout e of transmission was contaminated food.The cook wasn't the infection source bec ause the strain isolated from it had different genetype from epidemic strain. Conclusion Genetype methods could explore the epidemiolog ic relationship of isolates in a Shigellosis outbreak more accurately and more p rofoudly.