Depending on the selective advantages introduced in the recipient variety by the acquired GIs, the elements may undergo insertions, mutations or deletions (Kulasekara et al., 2006) , and the 89K PAI is no exception. We previously reported that three re-emerging S. suis 2 strains in China in 2007 all share the 89K PAI, and two of them had undergone gene losses/deletions . Further, using Roche NimbleGen microarray technology and PCR analysis, we found that several virulent (e.g. 606, 1941 and 8011) and avirulent (e.g. T15 and 2f) S. suis 2 strains carry only a portion of this island (unpublished data). The 89K element was also found to be partially included in strain 7996, one of the recipient strains used in our transfer experiments, albeit at a different location. Recently, published work suggests that S. suis strain BM407, which was isolated from a human meningitis case in Vietnam in 2004, contains two regions with extended similarity to 89K (Holden et al., 2009) . Structural and compositional analysis strongly suggests that both of these regions have the potential to undergo excision and transfer, just as 89K does.