FIG 1.

Phylogeography of human and animal Clostridium difficile RT078 strains. Maximum likelihood, midpoint-rooted phylogenetic tree of 248 genomes represents strains isolated from human (dark blue), animal (red), food (orange), and environmental (light blue) sources and collected from Europe (dark green), North America (purple), Asia (pink), and Australia (light green). Branches with bootstrap confidence values above 0.7 are shown as solid lines. The phylogeny demonstrates clear mixing of European and North American strains, indicating multiple transmission events between continents, and mixing of human and animal strains, indicating multiple transmissions events between these hosts. Closely related clusters (see Table 1) containing both human and animal isolates are labeled 1 through 6 and highlighted in yellow.