Whole genome sequencing of enterohemorrhagic Escherichia coli O157 to demonstrate the phylogeny and evolutionary groups

Fourty-two strains of enterohemorrhagic Escherichia coli O157 (O157) were analyzed by whole genome sequencing to demonstrate the phylogeny and evolutionary groups of the organism. Those strais had been already divided into clades defined by Manning et al. (PNAS 105:4868) and reivesed by Hirai et al. (Infect. Genet. Evol. 13:94). Among the 42 strains, three strains were ancestral O157 and remained 39 strains were Subgroup C (Feng et al., Emer. Infect. Dis. 13:1701; Leopold et al., PNAS 106:87113). Two of which showed positive reactions for beta-glucronidase and sorbitol fermentation, and the remained one showed positive reactions for beta-glucronidase. Re-sequencing analysis was done by mapping read data of those strains to reference genome (Sakai strain NC_002695.)