脉冲场凝胶电泳在一起慕尼黑沙门菌食源性暴发中的应用研究

Application of pulsed-field gel electrophoresis in a food-borne outbreak of Salmonella serotype Muenchen infection

目的脉冲场凝胶电泳（PFGE）在食源性疾病病原菌诊断中的应用。方法采集19例患者和18名厨师的肛拭子、9份自制冷饮、2份井水以及5例患者的急性期和恢复期血清。同时采集未发病学生大便10份，血清5份，作为正常人对照。用传统的方法进行致病菌的分离和表型鉴定，对所分离的菌株参照美国疾病预防控制中心（CDC）的实验方法用PFGE进行DNA分子分型，使用BioNumerics软件进行聚类分析。结果从19份食物中毒患者肛拭子中分离出14株慕尼黑沙门菌、从9份可疑食物中分离出3株慕尼黑沙门菌、从18名厨师肛拭子中分离出7株慕尼黑沙门菌，所分离菌株生化结果一致、耐药性相同，患者恢复期血清比急性期血清对所分离的菌株抗体有4倍以上增长。23株分离株的PFGE型完全一致。结论PFGE能直观判断肠道致病菌的亲缘关系，及时确定传染源、传播途径和流行范围，是有效控制食源性疾病大面积暴发的早期预警手段。

Objective To investigate the application of pulsed-field gel electrophoresis （PFGE） in food-borne outbreak. Methods Pathogens were isolated and further characteristics identified by traditional methods. The strains isolated were carried out with molecular typing with using PFGE. PFGE was performed by Izboratory Directions for molecular subtyping of Salmonella by PFGE （ CDC, USA） and the results of PFGE were analyzed by BioNumerics soft. Results Totally 14 Salmonella serotype Muenchen strains were isolated from 19 patients,3 of 9 suspicious foods were positive for S. muenchen and 7 strains were isolated from 18 cooks . The biochemistry characterization and antimicrobial susceptibility of all the strains isolated were the same. 23S. muenchen isolates were all shown indistinguishable by PFGE. Conclusion PFGE should play a key role in identifying the outbreak-associated isolates and distinguishing them from unrelated sporadic isolates. It might also demonstrate that the genetic fingerprints of serotype Muenchen isolates derived from patients were indistinguishable from those derived from drinks. PFGE might provide precise information on bacterial food-borne pathogens, promptly identify the source of infection, and effectively prevent from spreading. It should be one of the early warning method on controlling outbreak of the food-borne disease.