杭州地区相同分子型别的单核细胞增生李斯特菌临床和食品分离株基因组分析

Genomic analysis of Listeria monocytogenes of clinical and food isolates of same molecular type in Hangzhou,China

目的 研究杭州地区分子型别相同的临床和食品来源单核细胞增生李斯特菌在基因组水平的分子差异及进化关系。方法 利用高通量基因组测序和生物信息学分析方法对脉冲场凝胶电泳(Pulse-field gel electrophoresis,PFGE)型别一致的1株临床来源和6株食品来源的ST8型菌株进行基因组共线性、ncRNAs分布和毒力基因携带分析。联合NCBI Assembly数据库中ST8型菌株基因组,构建基于全基因组SNPs位点的进化树,进行溯源分析。结果 杭州地区临床和食品来源的菌株基因组共线性一致。菌株在毒力基因 lmo 0036和 lmo 2396的序列和 rli48, rli62和rliG 分子,质粒pLmA144的分布存在差异。基因组SNPs进化树显示ST8型菌株呈现高度同源。食品分离株中12-004与临床株12-103的进化上最接近,只有16个SNPs差异。结论 杭州市场近年肉类食品中存在遗传进化高度相似的一群ST8型单核细胞增生李斯特菌。杭州单核细胞增生李斯特菌临床分离株感染可能来自这群菌株。

We study the molecular differences and evolution relationships of clinical and food isolates of Listeria monocytogenes with same molecular types in Hangzhou. The genome block collinearity, non-coding RNAs and virulence genes distribution were analyzed by using high-throughput genome sequencing and bioinformatics analysis method for one clinical and six food-borne ST8 strains with same pulse-field gel electrophoresis (PFGE) patterns. Genomic phylogeny was applied to trace relationships by combining ST8 strains in NCBI Assembly database. Results showed that the genome of seven isolates in Hangzhou was consistently linear. These strains differed in virulence genes lmo 0036 and lmo 2396 and the distribution of ncRNAs rli48, rli62, rliG and plasmid pLmA144. The genomic SNPs phylogenetic tree showed ST8 strains a high degree of homology. The closest to the clinical strain 12-103 was the food isolate 12-004 which differed only by 16 SNPs. A large group of ST8 L. monocytogenes with high genetic similarity exists in the meat market in Hangzhou in recent years. The infection of clinical isolate is very likely from this group of strains.