单增李斯特菌感染一例患者的病因溯源

目的对一例单增李斯特菌感染患者的致病因素进行调查和溯源分析。方法在现场流行病学调查的基础上，对患者、患者家庭食品、厨房用具等进行样本采集并进行单增李斯特菌的菌株分离鉴定。对分离菌株的6个毒力基因（prfA、plcB、hly、actA、iap、inlA）进行检测，使用脉冲场凝胶电泳（PFGE）和多位点序列分型（MLST）技术进行分子分型分析，对分离菌株进行同源性分析。结果19份样本中共分离出6株单增李斯特菌，1株来自患者，2株来自厨房环境用具样本（冰箱冷藏室内壁涂抹1份和小号菜板涂抹1份），3株来自患者家庭中食物（分别是猪肝1份、甜玉米粒罐头1份和红焖牛肉罐头1份）。除冰箱冷藏室内壁涂抹和甜玉米粒罐头2个样本检出的菌株plcB毒力基因阴性外，另外5个毒力及其他菌株的所有毒力基因全部为阳性。分离菌株均为ST121型，PFGE带型100%一致。结论患者家庭厨房食用食物和环境皆被单增李斯特菌污染，引起交叉感染，致使患者感染发病。

Etiological analysis of a patient with Listeria monocytogenes infection

ObjectiveTo investigate the etiology and traceability of an infection case caused by Listeria monocytogenes.MethodsOn the basis of Field epidemiological investigation, samples of patient, foods, kitchen environmental appliances were collected for strain isolation and identification. Six pairs of virulence genes (prfA, plcB, hly, actA, iap, inlA) of positive strains were tested. The positive strains were analyzed by pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST) techniques. The homologous analysis was finally performed on the isolated strain.ResultsSix strains of Listeria monocytogenes were isolated, one from the case, two from the kitchen environmental kit, and three from the food of patient's family. In addition to the deletion of the virulence gene of the strain plcB detected by the two samples of the refrigerator inner wall and canned sweet corn, the other five virulence and all the virulence genes of other strains were all positive.. The isolated strains were all ST121 type, and the PFGE band type was 100% consistent.ConclusionThe reason for the prevalence of this patient was due to poor hygiene in the home kitchen and contamination of both food and the environment.