Figure. Maximum-likelihood phylogeny of STEC OX18 from a patient in Japan and other Escherichia coli strains. Isolate identifications of STEC OX18 are shown in bold. Colored boxes indicate collection countries, stx profiles, and symptoms of human carrier or source of the STEC OX18 isolates, as shown in the keys. Serotype and pathotype information of non-OX18 E. coli strains are shown in parentheses. The tree was rooted by E. fergusonii ATCC35469. AC, asymptomatic carrier; BD, bloody diarrhea; D, diarrhea; HUS, hemolytic uremic syndrome; STEC, Shiga toxin–producing E. coli; Stx, Shiga toxin. APEC, avian pathogenic E. coli; AIEC, adherent/invasive E. coli; EAEC, enteroaggregative E. coli; EPEC, enteropathogenic E.coli; ExPEC, extraintestinal pathogenic E. coli; UPEC, uropathogenic E. coli. Scale bar indicates number of substitutions per site.