The other S. suis strains, including 2 representative strains, 1 human isolate, and 132 porcine isolates, were positive for this assay; however, 16 porcine isolates of serotypes 20, 22, and 33 were negative ( Table 1). The other bacterial species listed in Table 2 did not generate any amplicons. On the other hand, when the DNAs of several taxonomically close relatives based on the recN gene sequence were examined by gdh PCR, S. gallinaceus and S. ovis showed amplicons of 688 bp, which was similar to the positive control ( Fig. 2).