The diarrheal response of humans to some classic serotypes of enteropathogenic Escherichia coli is dependent on a plasmid encoding an enteroadhesiveness factor

J Infect Dis. 1985 Sep;152(3):550-9. doi: 10.1093/infdis/152.3.550.


Isolates of the most common O serogroups of enteropathogenic Escherichia coli (EPEC) associated with infant diarrhea (designated class I) adhere to Hep-2 cells; the genes for this adhesin, termed EPEC adherence factor (EAF), are located on plasmids 50-70 MDa in size. Volunteers ingested 10(10) organisms of an O127:H6 Hep-2-adhesive class I strain (E2348/69) or its plasmid-minus, nonadhesive derivative. Diarrhea occurred in nine of 10 volunteers who ingested the parent strain (mean, 1,178 ml) but in only two of nine who took the plasmid-minus variant (mean, 433 ml; P less than .006). All volunteers ill from strain E2348/69 mounted serum IgA and IgG responses to a 94-kDa plasmid-associated outer membrane protein of E2348/69; this protein was found in other class I EPEC but not in enterotoxigenic or meningitic strains. The 50-70-MDa EAF plasmid seems necessary for full expression of pathogenicity in EPEC that exhibit Hep-2 adhesiveness. EPEC isolates of certain other, less common, O serogroups (O44, O86, and O114) are rarely Hep-2 adhesive. These EPEC, designated class II, possess distinct 50-70 MDa plasmids lacking EAF genes. Diarrhea was caused by 10(8) or 10(10) organisms of an O114:H2 class II EPEC strain (mean, 1,156 ml) in six of 11 volunteers. This result confirmed that class II EPEC are pathogenic by a mechanism not involving Hep-2 adhesiveness.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adhesins, Escherichia coli
  • Adhesiveness
  • Adolescent
  • Adult
  • Antibodies, Bacterial / analysis
  • Bacterial Outer Membrane Proteins / analysis
  • Bacterial Outer Membrane Proteins / genetics
  • Bacterial Outer Membrane Proteins / immunology
  • Bacterial Proteins / genetics*
  • Bacterial Toxins / biosynthesis
  • Diarrhea / microbiology*
  • Escherichia coli / genetics*
  • Escherichia coli / pathogenicity
  • Escherichia coli Infections / microbiology*
  • Humans
  • Immunoglobulin A / analysis
  • Immunoglobulin G / analysis
  • Plasmids*
  • Shiga Toxins


  • Adhesins, Escherichia coli
  • Antibodies, Bacterial
  • Bacterial Outer Membrane Proteins
  • Bacterial Proteins
  • Bacterial Toxins
  • Immunoglobulin A
  • Immunoglobulin G
  • Shiga Toxins