PREVENTION AND CHARACTERIZATION OF PERSISTENT COLONIZATION BY E. COLI O157:H7 AND OTHER SHIGA TOXIN-PRODUCING E. COLI (STEC) IN CATTLE

1) Determine and characterize molecular mechanisms promoting colonization, effective adherence, and persistence of Escherichia coli (E. coli) O157:H7 and other Shiga toxin-producing E. coli (STEC) in cattle. Evaluate the role of specific virulence factors in adherence of important non-O157:H7 STEC to tissue cultured cells and bovine intestinal tissues. 2) Understand the impact of bovine intestinal environment and immune responses on growth, adherence, and persistence of E. coli O157:H7 and other STECs in cattle. Determine the effects of signaling molecules produced in the bovine intestinal environment on selected virulence attributes of non-O157 STEC. 3) Conduct comparative analysis of bovine E. coli O157:H7 and STEC isolates of public health significance to identify components for use in developing rapid diagnostic tools and effective interventions; and 4) Develop and test efficacy of chemical, biological, subunit proteins, and whole cell vaccines to prevent or reduce colonization of cattle intestines by E. coli O157:H7 and STECs.