Pathogenesis
http://www.biotech.ubc.ca/faculty/finlay/EPEC.HTM
The characteristic trait of EPEC infection is the ability to attach and efface the intestinal epithelia which result in the formation of the actin pedestals seen above.
Four step model:
Stage One: Expression of bundle-forming pili, intimin, and surface associated filaments
Stage Two: Adherence via Bfp and EspA; Type III secretion of Tir causes actin rearrangements; Subsequent Tir modifications and insertion into the membrane.
Stage Three: Loss of EspA, binding between intimin and Tir, accumulation of actin beneath the adherence site
Stage Four: Massive cytoskeletal accumulation/pedestal formation
Fun fact:
The actin polymerization in the actin pedestals can be used by EPEC for movement on the epethelial surface at speeds up to .07μm/second.