比较基因组学推断出泰国和越南的鱼类致病性无乳链球菌存在两个不同的种群，血清型 Ia ST7 和血清型 III ST283。

Comparative genomics inferred two distinct populations of piscine pathogenic Streptococcus agalactiae, serotype Ia ST7 and serotype III ST283, in Thailand and Vietnam.

机构信息

Department of Aquaculture, Faculty of Fisheries, Kasetsart University, Bangkok, Thailand.

出版信息

Genomics. 2019 Dec;111(6):1657-1667. doi: 10.1016/j.ygeno.2018.11.016. Epub 2018 Nov 17.

DOI:10.1016/j.ygeno.2018.11.016

Abstract

The genomes of Streptococcus agalactiae (group B streptococcus; GBS) collected from diseased fish in Thailand and Vietnam over a nine-year period (2008-2016) were sequenced and compared (n = 21). Based on capsular serotype and multilocus sequence typing (MLST), GBS isolates are divided into 2 groups comprised of i) serotype Ia; sequence type (ST)7 and ii) serotype III; ST283. Population structure inferred by core genome (cg)MLST and Bayesian clustering analysis also strongly indicated distribution of two GBS populations in both Thailand and Vietnam. Deep phylogenetic analysis implied by CRISPR array's spacer diversity was able to cluster GBS isolates according to their temporal and geographic origins, though ST7 has varying CRISPR1-spacer profiles when compared to ST283 strains. Based on overall genotypic features, Thai ST283 strains were closely related to the Singaporean ST283 strain causing foodborne illness in humans in 2015, thus, signifying zoonotic potential of this GBS population in the country.

摘要

在过去的九年（2008-2016 年）里，研究人员从泰国和越南患病鱼类身上采集了 21 株无乳链球菌（B 群链球菌；GBS）的基因组并进行了测序和比较。根据荚膜血清型和多位点序列分型（MLST），GBS 分离株分为 2 组，i）血清型 Ia；ST7 和 ii）血清型 III；ST283。核心基因组（cg）MLST 和贝叶斯聚类分析推断的种群结构也强烈表明，在泰国和越南都存在两种 GBS 种群的分布。CRISPR 数组的间隔多样性所暗示的深度系统发育分析能够根据 GBS 分离株的时间和地理来源进行聚类，尽管与 ST283 菌株相比，ST7 的 CRISPR1-间隔体图谱有所不同。基于整体基因型特征，泰国 ST283 菌株与 2015 年导致新加坡人类食源性疾病的新加坡 ST283 菌株密切相关，这表明该国该 GBS 种群存在人畜共患的潜力。