Recent analyses of Streptococcus suis isolates using multilocus sequence typing (MLST) suggested the importance of sequence type (ST) 1 and ST27 complexes for animal hygiene and public health. In this study, to develop a novel polymerase chain reaction (PCR)-based screening method for identification of the important clonal groups, we examined the correlation between STs and distribution of four putative pilus gene clusters (srtBCD, srtE, srtF, and srtG clusters) among S. suis isolates from various origins. PCR analysis of putative pilus-associated genes in the clusters revealed that the srtBCD and srtG clusters were preferentially distributed to members of the ST1 and ST27 complex, respectively. In addition, profiling of three selected pilus-associated genes (sbp2, sep1, and sgp1) showed that all sbp2 +/sep1 -/sgp1 - and 96.2% of sbp2 -/sep1 -/sgp1 + isolates tested belonged to ST1 and ST27 complexes, respectively. On the other hand, 93.3% of isolates showing other sbp2/sep1/sgp1 profiles belonged to neither the ST1 nor ST27 complex. These results suggest that profiling of the three selected pilus-associated genes can be used as an easy screening method to monitor isolates important for S. suis infection.
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Takamatsu, D. et al. (2009) Vet. Microbiol. 138(1-2):132-139.