Spread of Streptococcus suis Sequence Type 7, China
Figure 2. Horizontal transfer events of virulence genes and conjugative transposon Tn916 with tetM in Streptococcus suis sequence types. The rooted maximum-parsimony tree was based on the concatenated sequences of 7 housekeeping genes used for multilocus sequence typing analysis of S. suis by using S. pneumoniae R6 as the outgroup. Virulence genes acquired by strains of various sequence types were from this study and other published papers. The colored labels indicate positive detection; uncolored labels indicate negative results for the virulence gene; no label indicates that the strain was not available for testing. The scale bar indicates a branch length corresponding to 100 character-state changes.