进出口食品中单核细胞增生李斯特菌脉冲场凝胶电泳分型研究

Typing of Listeria monocytogenes in import and export foods with PFGE

目的研究进出口食品中分离的单核细胞增生李斯特菌(LMO)之间分子分型特征和遗传相关性。方法参照美国PulseNet推荐的LMO脉冲场凝胶电泳(PFGE)标准方法,用限制性内切酶AscⅠ酶切LMO染色体DNA进行PFGE试验。用BioNumerics软件对不同地区分离的LMO进行比对,分析菌株之间的相似度。结果 24株LMO分成20种PFGE型,菌株之间的相似度在44.45%～100%。来源于加拿大的LMO16、美国的LMO18、丹麦的LMO13,丹麦的LMO7和顺德的LMO22,广州的LMO21和山西的LMO8,分别有相同的PFGE型,相似度达到100%。结论进出口食品中分离的LMO在整体上表现出较大的遗传多样性,但部分菌株有一定程度的相关性。

Objective To investigate the molecular type and genetic correlation of Listeria monocytogenes （LMO） isolated from imported and exported foods.Methods Pulsed-field gel electrophoresis （ PFGE） standard method recommended by american PulseNet for typing LMO was applied.The chromosomal DNA of L.monocytogenes was digested by restriction enzyme Asc Ⅰ and analyzed by PFGE.The PFGE patterns of L.monocytogenes strains isolated from different areas were compared by using BioNumberics software to analyze the similarity between strains.Results Twenty-four L.monocytogenes strains were grouped into 20 PFGE subtypes by the similarity of PFGE pattern ranged from 44.45% to 100% .Particularly,it was identified that there were three subtype strain groups,each group sharing with the same PFGE pattern,and the similarity reaching 100% ： the first group including LMO16 from Canada,LMO18 from America and LMO13 from Denmark,the second group including LMO7 from Denmark and LMO22 from Shunde,and the third group including LMO21 from Guangzhou and LMO8 from Shanxi.Conclusion Generally,much genetic diversity was shown in Listeria monocytogenes isolated from import and export foods,but the correlations among strains are existed to some extent.