Clonal relations of atypical enteropathogenic Escherichia coli O157:H16 strains isolated from various sources from several countries

FEMS Microbiol Lett. 2012 Dec;337(2):126-31. doi: 10.1111/1574-6968.12017. Epub 2012 Oct 19.

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.

MeSH terms

  • Adhesins, Bacterial / genetics
  • Americas
  • Animals
  • Cluster Analysis
  • Electrophoresis, Gel, Pulsed-Field
  • Escherichia coli Infections / microbiology*
  • Escherichia coli O157 / classification*
  • Escherichia coli O157 / genetics
  • Escherichia coli O157 / isolation & purification*
  • Escherichia coli Proteins / genetics
  • Europe
  • Genetic Variation*
  • Genotype
  • Humans
  • Meat / microbiology
  • Multilocus Sequence Typing
  • Virulence Factors / genetics
  • Water Microbiology

Substances

  • Adhesins, Bacterial
  • Escherichia coli Proteins
  • Virulence Factors
  • eaeA protein, E coli