Epithelial cell invasion: an overlooked property of enteropathogenic Escherichia coli (EPEC) associated with the EPEC adherence factor

J Infect Dis. 1989 Sep;160(3):452-9. doi: 10.1093/infdis/160.3.452.


In order to investigate the ability of enteropathogenic Escherichia coli (EPEC) to invade epithelial cells, 24 strains of diarrhea-causing E. coli were studied with a HEp-2 cell-gentamicin invasion assay. Invasive ability was expressed as the percentage of the inoculum surviving gentamicin after incubation of bacteria with HEp-2 cells. Geometric mean survival of EPEC strains possessing the EPEC adherence factor (EAF+ EPEC) was 5.177%, which was significantly greater than survival of enteroinvasive E. coli (EIEC) strains (1.871%). EPEC strains lacking EAF (EAF-EPEC), enterotoxigenic E. coli (ETEC), and enterohemorrhagic E. coli (EHEC) were significantly less invasive (geometric mean survival, 0.032%, 0.013%, and 0.009%, respectively). The variation in bacterial recovery was not due to differences in the number of HEp-2 cells remaining attached to the plates, as measured by the retention of crystal violet stain in parallel assays. Transmission electron microscopy confirmed the presence of many intracellular EAF+ EPEC and EIEC, whereas EAF- EPEC, EHEC, and ETEC were found primarily outside the cells. Epithelial cell invasion is an overlooked property of EAF+ EPEC of potential relevance in disease pathogenesis.

Publication types

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

MeSH terms

  • Bacterial Adhesion*
  • Bacterial Proteins / analysis*
  • Cell Line
  • Cells, Cultured
  • Epithelium / microbiology
  • Epithelium / ultrastructure
  • Escherichia coli / pathogenicity*
  • Escherichia coli / physiology
  • Escherichia coli / ultrastructure
  • Humans
  • Microscopy, Electron


  • Bacterial Proteins