猪链球菌wzy基因与血清型别的相关性分析

Relationship between wzy genes and serotype of Streptococcus suis

目的分析wzy基因序列与血清分型相关性,评价基于wzy基因的基因组水平血清分型的可行性。方法建立了33个已知血清型(1～31,33与1/2型)及21种新型cps型别(NCL1～20与Chz型)的wzy基因的氨基酸序列数据库,用来检索公开发表的767个有传统血清分型结果的基因组序列,以确定它们的分子血清型别,并与其用传统血清分型结果进行比对。结果 767个基因组中,有765个基因组含有1种且仅含有1种数据库中的wzy基因,剩余的2个基因组携带数据库中没有的wzy基因,本研究中将其cps型别命名为NCL21。94.13%(722/767)基因组的分子血清型别与其传统血清分型结果一致。在二者结果有差异的基因组中,其cps基因簇的核苷酸序列与其传统血清分型结果相应的血清型标准菌株cps序列有明显的差异。结论基因组水平检测血清型特异性的wzy基因的分型策略,显著优于传统的血清分型方法。

Objective To study the relationship between serotype-specific wzy genes and serotype of Streptococcus suis and evaluate the feasibility of Whole-Genome Sequencing(WGS)-based serotyping strategy for the serotype-specific wzy genes.Methods Amino acid database of 54 wzy genes(1–31,33,1/2,NCL1-20 and Chz) for serotyping was established.All 767 S.suis isolates available with WGS data and conventional serotype information were subjected to WGS-based serotyping by using the database.Results Among the 767 genomes,1 of 54 wzy genes was detected in 765 genome sequences.The remaining 2 genomes carried a novel wzy gene,named as NCL21 in this study.WGS-based serotyping predicted serotype of94.13%(722/767) genomes,consistent with conventional serotyping.Discrepancy of two methods was observed in 45 genomes.The cps sequences of these genomes were obviously different from those of the serotype reference strains indicated by conventional serotyping method.Conclusion WGS-based serotyping strategy for the serotype-specific wzy genes of S.suis is superior to conventional serotyping method.