Fig. (4) Phylogenetic tree of the 79 Streptococcus zooepidemicus isolates obtained from Thoroughbred horses in Korea. The phylogenetic tree was constructed with InfoQuest software Ver. 4.5 (Bio-Rad). Clusters of individual unlinked patterns within the study sample are displayed as a single unrooted branch. Analysis of the genetic origins of the S. zooepidemicus strains isolated from Jeju and Jangsu showed that the isolated strains have different genetic origins.