T4SS-mediated transfer of 89K PAI in S. suis 2 1671 7996 strain, both isolated from the Netherlands (Table 1) . However, conjugation experiments using other serotypes of S. suis (serotypes 7 and 9) and other streptococcal species (S. sanguinis and S. agalactiae) as recipients were performed but without success, suggesting that the 89K transfer may be species-and serotype-specific.