一株ST477型单增李斯特菌的全基因组测序及inlA基因遗传多样性

Whole-genome sequencing of a Listeria monocytogenes ST477 and genetic diversity of inlA gene

摘要:

【背景】单增李斯特菌是一种重要的条件致病菌，不同型别菌株在宿主范围和毒力等方面存在差异。内化素基因inlA在入侵宿主上皮细胞中具有重要作用。【目的】研究单增李斯特菌序列型(Sequence type，ST)为477菌株的基因组特征及内化素基因inlA的遗传多样性。【方法】使用相关软件对测序数据进行多位点序列分型(Mutilocus sequence typing，MLST)、单核苷酸多态性(Single nucleotide polymorphism，SNP)及基因inlA遗传多样性分析。【结果】MLST进化分析结果显示，分离自不同国家的菌株具有较近亲缘关系。以分离自中国食品的ST477型菌株为参考菌株，通过SNP分析表明，加拿大食品中的ST9型菌株发生的突变位点最少(91?93个)。7株复合克隆系(Clonal complex，CC)为9的菌株其inlA基因序列间核苷酸相似性为29.8%?100%。【结论】初步分析了ST477型别菌株的进化及基因组特征，同时研究了部分CC9克隆系菌株inlA基因突变情况，为研究ST477型别菌株的进化及单增李斯特菌的毒力提供基础数据。

Abstract:

[Background] Listeria monocytogenes is an important opportunistic pathogen. There are some differences in host range and virulence among different strains. Internalin gene inlA play an important role in host epithelial cells invasion. [Objective] Analyze the genomic characteristics of the Listeria monocytogenes STS477 isolate and investigate the genetic diversity of gene inlA. [Methods] Mutilocus sequence typing (MLST), single nucleotide polymorphism (SNP) and inlA genetic diversity were analyzed based on the sequencing data with software. [Results] MLST analysis showed that isolates from different countries have close relationship. Based on the SNP analysis, ST9 strains isolated from Canadian food owned the fewest mutation sites (91?93) by aligning six CC9 isolates against the chromosome of the ST477. The nucleotide homology of seven inlA gene sequences was 29.8%?100%. [Conclusion] We preliminarily analyzed the evolution of ST477 isolate and investigate the mutation type of inlA gene belonging to CC9. This study provides basic data for analysis of the evolution of ST477 strains and the virulence of L. monocytogenes.