title: Presence of virulence and fitness gene modules of enterohemorrhagic Escherichia coli in atypical enteropathogenic Escherichia coli O26.
abstract: Enterohemorrhagic Escherichia coli (EHEC) strains of serogroup O26 cause hemolytic-uremic syndrome (HUS) whereas atypical enteropathogenic E. coli (aEPEC) O26 typically cause uncomplicated diarrhea but have been also isolated from HUS patients. To gain insight into the virulence of aEPEC O26, we compared the presence of O island (OI) 122, which is associated with enhanced virulence in EHEC strains, among aEPEC O26 and EHEC O26 clinical isolates. We also tested these strains for the high pathogenicity island (HPI) which is a fitness island. All 20 aEPEC O26 and 20 EHEC O26 investigated contained virulence genes located within OI-122 (efa1/lifA, nleB, nleE, ent). In both aEPEC O26 and EHEC O26, OI-122 was linked to the locus for enterocyte effacement, forming a mosaic island which was integrated in pheU. Moreover, strains of these two pathotypes shared a conserved HPI. These data support a close relatedness between aEPEC O26 and EHEC O26 and have evolutionary implications. The presence of OI-122 in aEPEC O26 might contribute to their pathogenic potential.
authors.affiliation: Institute for Hygiene, and the National Consulting Laboratory on Hemolytic Uremic Syndrome, University of Münster, Robert Koch Strasse 41, D-48149 Münster, Germany. mbiela@uni-muenster.de
authors.forename: Martina
authors.initials: M
authors.lastname: Bielaszewska
authors.forename: Anne-Katharina
authors.initials: AK
authors.lastname: Sonntag
authors.forename: M Alexander
authors.initials: MA
authors.lastname: Schmidt
authors.forename: Helge
authors.initials: H
authors.lastname: Karch
mesh_terms: D004247:DNA / Q000737:chemistry / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics* / Q000276:immunology / Q000472:pathogenicity; D004927:Escherichia coli Infections / Q000382:microbiology*; D029968:Escherichia coli Proteins / Q000737:chemistry / Q000235:genetics; D019143:Evolution, Molecular; D016680:Genome, Bacterial / Q000235:genetics*; D044404:Genomic Islands / Q000235:genetics / Q000276:immunology; D006801:Humans; D016133:Polymerase Chain Reaction; D014774:Virulence
chemical_list: D029968:Escherichia coli Proteins; D004247:DNA