Streptococcus suis strains are classified into 35 serotypes on the basis of the antigenicity of their capsular polysaccharides (CPSs). CPS synthesis genes are known to be clustered on the chromosome (cps gene cluster). We sequenced and analyzed the entire cps gene clusters of all 35 serotypes. A total of 672 cps genes were identified in the 35 cps gene clusters. 197 of them were identified as serotype-specific by clustering analysis; cps gene clusters of serotypes 1, 2, 1/2 and 14 did not contain serotype-specific genes. Because of the presence of genes encoding flippase (wzx) and polymerase (wzy) in all cps gene clusters, CPSs of all serotypes were thought to be synthesized by the Wzx/Wzy pathway. Additionally, our data suggests entire or partial cps gene clusters transferring between S. suis strains, as well as the influence of spontaneous mutations in a single or a few genes on the antigenicity of some serotypes.
(Bacterial and Parasitic Disease Research Division)
References:
Okura M. et al (2013) Appl. Environ. Microbiol. 79(8):2796-2806
