温州市食品中小肠结肠炎耶尔森氏菌分布及分子分型研究

Distribution and molecular typing analysis of Yersinia enterocolitica in food in Wenzhou

目的 了解温州市食品中小肠结肠炎耶尔森氏菌的分子分型及分布特征。方法 4℃增菌后用选择性培养基对食品中的小肠结肠炎耶尔森氏菌进行分离鉴定,分析阳性菌株的生物型、血清型、毒力基因型、耐药性和脉冲场凝胶电泳(PFGE)分子型别。结果 采集6类食品,共676份样品,其中68份样品检出69株小肠结肠炎耶尔森氏菌,检出率为10.1%(68/676)。调理肉制品检出率最高(20.5%,9/44),其次为速冻食品(17.2%,11/64)。95.7%(66/69)的分离株为生物1A型,生物血清型以1A/O∶5(29.0%)为主,其次为1A/O∶8(14.5%);88.4%(61/69)的菌株仅携带ystB基因,检出1株4/O∶3型菌株携带毒力基因ail、ystA、yadA、virF。分离株对14种抗菌药物的敏感率达到94%以上。32株血清已分型菌株,分为29种PFGE带型。结论 温州市食品中存在一定程度的小肠结肠炎耶尔森氏菌污染,且检出致病性小肠结肠炎耶尔森菌,菌株耐药率处于较低水平,分子分型提示菌株呈高度遗传多态性。

Objective To investigate the distribution and molecular typing characters of Yersinia enterocolitica in food in Wenzhou.Methods After pre-enrichment of samples at 4 ℃,the selective media was used for the isolation and identification of Yersinia enterocolitica from food. The biotype,serotype,virulence genotype,drug resistance and pulsed field gel electrophoresis,(PFGE) molecular typing of the isolated strains were analyzed.Results Among 676 samples in 6categories,69 Yersinia enterocolitica strains were isolated from 68 samples,with a positive rate of 10. 1%(68/676). The detection rate of prepared meat products was the highest(20. 5%,9/44),followed by quick-frozen food(17. 2%,11/64).Biotype 1A accounted for 95. 7%(66/69) of the isolates,and the predominant bioserotype was 1A/O∶5(29. 0%),followed by 1A/O∶8(14. 5%). 88. 4%(61/69) of the strains only harbored ystB gene. Particularly,there was a bioserotype 4/O∶3 strain carried the virulence gene of ail,ystA,yadA and virF. The sensitivity rates of the isolates to 14 kinds of antibiotics were over 94%. Thirty two serotyped strains were divided into 29 PFGE patterns.Conclusion Food was contaminated by Yersinia enterocolitica to some degree in Wenzhou,and the pathogenic strain was detected. The antibiotic resistance rate of Yersinia enterocolitica was at a low level,and PFGE suggested highly genetic polymorphism.