1. Phylogenetic tree of intestinal pathogenic E. coli.
Phylogenetic tree of intestinal pathogenic E. coli. E. coli strains can be grouped into 5 main phylogenetic groups: A (blue), B1 (green), B2 (brown), D (pink), and E (red). Shigella/EIEC also form additional phylogroups (black). Pathotypes do not always group together in the same phylogroup. The hybrid EAEC and STEC strains are denoted with both an open square and open circle. Unmarked strains are either commensal, extraintestinal pathogenic E. coli (ExPEC), or avian-pathogenic E. coli (APEC). ETEC strains are isolated from both humans and animals, while DAEC is not represented in the phylogenetic tree. (Adapted from reference 19, which was published under a Creative Commons license.)‏
Matthew A. Croxen et al. Clin. Microbiol. Rev. 2013; doi: /CMR