上海市肠炎沙门菌流行特征和分子分型研究

Astudy on the epidemiological characteristics and molecular typing of Salmonella enterica serovar Enteritidis in Shanghai

[目的]分析上海市2006—2007年肠炎沙门菌菌株,了解上海市肠炎沙门菌分子流行病学特征。[方法]回顾2002—2007年肠炎沙门菌食品株来源并与肠炎沙门菌腹泻株作耐药性比较;对2006—2007年全球沙门菌监测(GSS)病例和食品分离的肠炎沙门菌进行表型验证、药敏试验和脉冲凝胶电泳(PFGE)分析。[结果]2006—2007年肠炎沙门菌在本市非伤寒沙门菌病例中列首位,而80%的食品株源自禽及禽肉制品,食品株的抗生素耐药性高于腹泻株。2007年肠炎沙门菌腹泻株的耐药谱和2006年有较大差异。包括13株食品株在内共76株肠炎菌株可分为21种PFGE带型,遗传同源性接近80%,优势带型依次为3型(34株)、1型(12株)、2型(5株)和5型(5株),除2型外均发现有与腹泻株同型的食源株。2006和2007年的PFGE 1/2型病例分别为4例和12例。[结论]上海市肠炎沙门菌病例与食用污染的鸡肉等禽类制品有密切关系,PFGE 3型肠炎沙门菌是目前上海市肠炎沙门菌流行株的优势菌型,2007年发现由鹅肝传播的1/2型肠炎沙门菌可能是3型的变异株并有取代之成为流行菌株的趋势。开展对腹泻病例和食物链的综合监测和以实验室为主的实时分子分型检测能快速预警肠炎沙门菌散在爆发和追溯污染源。

[ Objective ] To study the molecular epidemiological characteristics of Salmonella enterica serovar Enteritidis （ S. Enteritidis） strains in Shanghai from year 2006 to 2007. [ Methods ] A retrospective analysis from year 2002 to 2007 was performed to explore the source of food - borne S. Enteritidis strains and compare its antibiotic resistance with strains isolated from diarrheal patients. Data of S. Enteritidis strains of patient and food of Global Salm - Surv （GSS） from year 2006 to 2007 were tested, including phenotype confirmation, antibiotic resistance and pulsed - field gel electrophoresis （PFGE） analysis. [ Results ] S. Enteritidis was the topmost strain in diarrheal patients caused by non - typhi Salmonella in year 2006 to 2007, in Shanghai. 80% strains of food - borne S. Enteritidis were obtained from poultry and their products. The antibiotic resistance of food isolates was higher than those from clinical isolates. The drug resistance spectrum of diarrhea patients isolates in year 2006 was different from that in year 2007. 76 strains including 13 food - borne strains belonged to 21 PFGE pattern combinations, and their genetic similarity was higher than 80%. The major PFGE subtype was type 3 （ 34strains）, type 1 （ 12 strains）, type 2 （ 5 strains） and type 5 （ 5 strains）, Every strain from food had been matched with PFGE subtype strains in diarrhea patients except subtype 2. The number of homology case of diarrhea patients and food caused by subtype 1/2 were 4 and 12 in year 2006 and 2007. [ Conclusion ] There is close relationship between diarrhea patients of S. Enteritidis and contaminated poultry（chicken） in Shanghai. The PFGE subtype 3 is the predominant epidemic strain. The PFGE subtype 1/2 isolated from goose liver in year 2007 may be a viriety of subtype 3, and may tend to replace the predominant strain. This study suggests that rapid control and forecast the potential outbreak eases of S. Enteritidis and trace the suspected source of contamination by combining the surveillance of clinical patients and food chain, including the real - time molecular typing in laboratory.