Intimin-mediated tissue specificity in enteropathogenic Escherichia coli interaction with woman intestinal organ cultures

The hallmark of enterohemorrhagic Escherichia coli (EHEC) and enteropathoge nic E. coli (EPEC) adhesion to cultured human host cells is intimate attach ment and the formation of attaching and effacing (A/E) lesions. Recently, E HEC O157:H7 was shown to induce A/E Lesions on human intestinal explants. U nlike EPEC, which colonized the small intestine, EHEC adhesion was restrict ed to follicle-associated epithelium (FAE) of ileal Peyer's patches. This s tudy tested the hypothesis that the bacterial adhesin intimin contributes t o tissue specificity. Complementing the eae gene mutation in CVD206 (derive d from EPEC strain E2348/69) with EPEC eae(alpha) (encoding intimin-alpha) restored the ability to colonize small intestinal mucosa like the parent st rain, In contrast, complementing with EHEC eae(gamma) (encoding intimin-gam ma) resulted in the strain adhering and inducing A/E lesion on Peyer's patc hes, similar to EHEC. An intimin-gamma-positive O55:H7 EPEC also targeted F AE. Thus, intimin contributes to the tissue specificity of A/E lesion-formi ng microbial pathogens.