Complete Genome Sequence and Comparative Genome Analysis of Enteropathogenic Escherichia Coli O127:H6 Strain E2348/69

J Bacteriol. 2009 Jan;191(1):347-54. doi: 10.1128/JB.01238-08. Epub 2008 Oct 24.

Abstract

Enteropathogenic Escherichia coli (EPEC) was the first pathovar of E. coli to be implicated in human disease; however, no EPEC strain has been fully sequenced until now. Strain E2348/69 (serotype O127:H6 belonging to E. coli phylogroup B2) has been used worldwide as a prototype strain to study EPEC biology, genetics, and virulence. Studies of E2348/69 led to the discovery of the locus of enterocyte effacement-encoded type III secretion system (T3SS) and its cognate effectors, which play a vital role in attaching and effacing lesion formation on gut epithelial cells. In this study, we determined the complete genomic sequence of E2348/69 and performed genomic comparisons with other important E. coli strains. We identified 424 E2348/69-specific genes, most of which are carried on mobile genetic elements, and a number of genetic traits specifically conserved in phylogroup B2 strains irrespective of their pathotypes, including the absence of the ETT2-related T3SS, which is present in E. coli strains belonging to all other phylogroups. The genome analysis revealed the entire gene repertoire related to E2348/69 virulence. Interestingly, E2348/69 contains only 21 intact T3SS effector genes, all of which are carried on prophages and integrative elements, compared to over 50 effector genes in enterohemorrhagic E. coli O157. As E2348/69 is the most-studied pathogenic E. coli strain, this study provides a genomic context for the vast amount of existing experimental data. The unexpected simplicity of the E2348/69 T3SS provides the first opportunity to fully dissect the entire virulence strategy of attaching and effacing pathogens in the genomic context.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Comparative Genomic Hybridization / methods
  • Conserved Sequence
  • DNA, Bacterial / genetics
  • DNA, Circular / genetics
  • Diarrhea / microbiology
  • Enteropathogenic Escherichia coli / genetics*
  • Enteropathogenic Escherichia coli / pathogenicity
  • Genes, Bacterial / genetics
  • Genome, Bacterial*
  • Humans
  • Infant
  • Plasmids
  • Translocation, Genetic
  • Virulence / genetics

Substances

  • DNA, Bacterial
  • DNA, Circular