2014-2019年阜阳市食品和病人分离单增李斯特菌的分子特征分析

Molecular characteristics of Listeria monocytogenes isolated from food and patients in Fuyang City,2014-2019

目的比较分析阜阳市食品和病人分离单增李斯特菌的毒力基因、分子型别,建立阜阳市单增李斯特菌分子特征信息数据库,为防控单增李斯特菌病提供科学依据。方法对阜阳市2014-2019年分离自食品和病人的55株单增李斯特菌,用聚合酶链反应(PCR)检测其毒力基因prfA、plcB、hly、actA、iap、inlA;用脉冲场凝胶电泳(PFGE)技术进行分子分型及同源性分析;用多位点序列分型(MLST)技术进行分子分型和聚类分析。结果 55株单增李斯特菌全部携带prfA、plcB、hly、actA、iap、inlA基因;PFGE将其分为21个带型,相似度60.3%~100%;MLST将其分为14个ST型,ST9型为优势型别;3株病人分离菌株的PFGE带型和ST型互不相同,其中2株病人来源菌株分别与食品分离株具有相同PFGE带型和ST型。结论阜阳市食品和病人中分离的单增李斯特菌均携带6个毒力基因,食品分离菌株的分子型别呈现出多样性,其中存在同型别单增李斯特菌持续性污染现象,病人分离菌株具有与食品来源菌株相同的PFGE带型和ST型,提示食源性感染的风险较高。

The aims of this study were to investigate the pathogenicity and molecular types of Listeria monocytogenes isolated from food and patients,to establish a database of molecular characteristics of L.monocytogenes and to provide a reference for the prevention and control of listeriosis in Fuyang City.A total of 55 L.monocytogenes strains were detected for the virulence genes prfA,plcB,hly,actA,iap and inlA by PCR,and subtyped by pulsed field gel electrophoresis(PFGE)and multi-locus sequence typing(MLST).Six virulence genes were found to be carried by all L.monocytogenes strains.The strains were divided into 21 pulsotypes(PT)and 14 sequence types(ST),among which ST9 was predominant.Three L.monocytogenes strains from clinical cases showed different pulsotypes and sequence types.Two clinical isolates showed an identical PFGE pattern and sequence type to those of some food isolates.The L.monocytogenes strains isolated from food and clinical cases in Fuyang showed genetic diversity.The strains from food and clinical cases with identical PT and ST types implied a potential link between food contamination and human infections.