Genetic analysis of the cps gene clusters in Streptococcus suis and development of a novel genetic typing method that contributes to serotyping

猪链球菌是一种重要的细菌，可引起猪和人的严重疾病。根据其荚膜多糖（CPs）的抗原性，猪链球菌可分为30多种血清型。在这项研究中，我们分析了猪链球菌cps基因簇的完整集合。我们的数据暗示了整个或部分cps基因簇在猪链球菌之间转移的可能性，以及单个或少数基因的自发突变对某些血清型抗原性的影响。这些基因转移的积累和小规模突变可能产生了猪链球菌CPs的抗原多样性。此外，通过针对几种血清型中保守的基因和我们分析中发现的血清型特异性基因，我们开发了基于多重pcr的cps分型方法，该方法由两个步骤组成，有助于猪链球菌的血清分型。

Streptococcus suis is an important bacterium which can cause severe disease in pigs and humans. S. suis strains are classified into more than 30 serotypes on the basis of the antigenicity of their capsular polysaccharides (CPs). In this study, we analyzed the complete set of S. suis cps gene clusters. Our data implied the possibility of the transfer of the entire or partial cps gene clusters among S. suis strains, as well as the influence of spontaneous mutations in a single or a few genes on the antigenicity of some serotypes. Accumulation of these gene transfers and small-scale mutations may have generated the antigenic diversity of S. suis CPs. In addition, by targeting the genes conserved in several serotypes and the serotype-specific genes identified in our analysis, we have developed multiplex PCR-based cps-typing method composed of 2 steps that contributes to the serotyping of S. suis.