The locus of enterocyte effacement pathogenicity island of Shiga toxin-producing Escherichia coli O157:H7 and other attaching and effacing E. coli.

INTRODUCTION Shiga toxin-producing E. coil (STEC) O157:H7 and enteropathogenic E. coil (EPEC) produce a characteristic histopathology on intestinal epithelial cells known as attaching and effacing (AlE). The characteristics of this pattern includes effacement of epithelial cell microvilli and intimate adherence between the bacterium and the epithelial cell membrane. Marked cytoskeletal changes are seen directly beneath the adherent bacterium, including accumulation of polymerized actin, and the development of pedestal-like structures upon which the bacteria sit. Tzipori et al. (20) first reported the attaching and effacing histopathology in gnotobiotic piglets infected with STEC O157: H7 and it has since been reported in variety of animal species as well as with cultured epithelial cells infected with O157: H7 (reviewed in (14)). This pattern was first described for EPEC and it has been best characterized in this pathogen.