IDENTIFYING BACTERIAL FACTORS INVOLVED IN BOVINE COLONIZATION: A COMPARATIVE GENOMICS APPROACH TO ADHERENCE IN SHIGA TOXIN-PRODUCING E. COLI

The major long-term goal of this project is to ensure a safe and healthy food supply by eradicating or reducing carriage of Shiga toxin-producing E. coli (STEC) in thebovine reservoir. The molecular mechanisms that allowE. colito adhere to the bovine recto-anal junction(RAJ) are not fully understood, in part because studies of STEC adherencehave historically focused on human cell culture models. This discrepancy must be addressed in order to properly target STEC at the site of colonization in its animal reservoir. We therefore propose to identify aset of bovine-specificE. coliadherence factors using coculture and comparative genomics.Our objectives are to (1) quantify the adherence of bovineE. coliisolates to RAJ squamous epithelial (RSE) cells isolated directly from cattle; (2) determine the pangenome of these isolates and identify genes associated with adherence; and (3) evaluate the differential expression of adherence genes in coculture with RSE cells.