Characterization of Colonization of Shiga Toxin-producing Escherichia coli (STEC) in Cattle and Strategies for Effective Preharvest Control

Since antibiotics are neither recommended nor used for STEC treatment in humans or carrier-animals, strategies as described in the National Strategy for Combating Antibiotic Resistant Bacteria (CARB; 1) are needed and will be investigated for STEC control in cattle as exemplified in the following objectives: Objective 1: Understand the impact of the bovine intestinal environment, especially at the rectoanal junction, and the molecular mechanisms that promote or inhibit colonization, adherence, and persistence of STEC in cattle and develop intervention strategies to control STEC colonization. Subobjective 1A: Identify bacteria in the rectoanal junction (RAJ) microbiome that could effectively interfere with STEC colonization for possible use in probiotic applications. Subobjective 1B: Identify bacterial ligands and tissue receptors involved in STEC adherence to the RAJ. Objective 2: Formulate and assess the efficacy of vaccines for controlling STEC colonization of cattle based on whole-cell and subunit vaccines and identify proteins and epitopes conserved in STEC. Objective 3: Define potential biomarkers using systems-based approaches that will allow the development of rapid diagnostic tests to identify STEC-colonized cattle.