title: Epithelial cell invasion: an overlooked property of enteropathogenic Escherichia coli (EPEC) associated with the EPEC adherence factor.
abstract: 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.
authors.affiliation: Division of Geographic Medicine and Infectious Diseases, New England Medical Center-Tufts University School of Medicine, Boston, Massachusetts 02111.
authors.forename: M S
authors.initials: MS
authors.lastname: Donnenberg
authors.forename: A
authors.initials: A
authors.lastname: Donohue-Rolfe
authors.forename: G T
authors.initials: GT
authors.lastname: Keusch
mesh_terms: D001422:Bacterial Adhesion; D001426:Bacterial Proteins / Q000032:analysis*; D002460:Cell Line; D002478:Cells, Cultured; D004848:Epithelium / Q000382:microbiology / Q000648:ultrastructure; D004926:Escherichia coli / Q000472:pathogenicity* / Q000502:physiology / Q000648:ultrastructure; D006801:Humans; D008854:Microscopy, Electron
chemical_list: D001426:Bacterial Proteins