title: Clonal relations of atypical enteropathogenic Escherichia coli O157:H16 strains isolated from various sources from several countries.
abstract: Atypical enteropathogenic Escherichia coli (aEPEC) is comprised of a large heterogeneous group of strains and serotypes that carry the intimin gene (eae) but no other EPEC virulence factors. In a previous study, we examined a few aEPEC strains of O157:H16 serotype from the U.S. and France and found these to be nearly homologous, and speculated that the same strain had been disseminated or perhaps they are part of a large clonal group that exists worldwide. To test that hypothesis, we examined additional 45 strains isolated from various sources from 4 other countries and determined that although there are a few eae-negative O157:H16 strains, most are aEPEC that carried eae and specifically, the ε-eae allele. Analysis by pulsed field gel electrophoresis (PFGE) and multilocus sequence typing showed that as a whole, O157:H16 strains are phylogenetically diverse and have different sequence types and PFGE profiles. But the aEPEC strains within the O157:H16 serotype, regardless of the eae allele carried, are a highly conserved and homologous group of sequence type (ST)-171 strains that shared similar PFGE profiles. These aEPEC strains of O157:H16 serotype are not closely related to any of the major EPEC and enterohemorrhagic E. coli clonal lineages and appear to be part of a large clonal group that are prevalent worldwide.
authors.affiliation: Division of Microbiology, FDA, College Park, MD 20740, USA. peter.feng@fda.hhs.gov
authors.forename: Peter C H
authors.initials: PC
authors.lastname: Feng
authors.forename: Christine
authors.initials: C
authors.lastname: Keys
authors.forename: David W
authors.initials: DW
authors.lastname: Lacher
authors.forename: Lothar
authors.initials: L
authors.lastname: Beutin
authors.forename: Adriana
authors.initials: A
authors.lastname: Bentancor
authors.forename: Annet
authors.initials: A
authors.lastname: Heuvelink
authors.forename: Jan E
authors.initials: JE
authors.lastname: Afset
authors.forename: Valeria
authors.initials: V
authors.lastname: Rumi
authors.forename: Steven
authors.initials: S
authors.lastname: Monday
mesh_terms: D018829:Adhesins, Bacterial / Q000235:genetics; D000569:Americas; D000818:Animals; D016000:Cluster Analysis; D016521:Electrophoresis, Gel, Pulsed-Field; D004927:Escherichia coli Infections / Q000382:microbiology*; D019453:Escherichia coli O157 / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification*; D029968:Escherichia coli Proteins / Q000235:genetics; D005060:Europe; D014644:Genetic Variation; D005838:Genotype; D006801:Humans; D008460:Meat / Q000382:microbiology; D058885:Multilocus Sequence Typing; D037521:Virulence Factors / Q000235:genetics; D014871:Water Microbiology
chemical_list: D018829:Adhesins, Bacterial; D029968:Escherichia coli Proteins; D037521:Virulence Factors; C073819:eaeA protein, E coli