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ARS Home » Midwest Area » Ames, Iowa » National Animal Disease Center » Food Safety and Enteric Pathogens Research » Research » Research Project #438679

Research Project: Intestinal Microbial Ecology and Non-Antibiotic Strategies to Limit Shiga Toxin-Producing Escherichia coli (STEC) and Antimicrobial Resistance Transmission in Food Animals

Location: Food Safety and Enteric Pathogens Research

Project Number: 5030-32000-225-000-D
Project Type: In-House Appropriated

Start Date: Dec 29, 2020
End Date: Dec 28, 2025

Objective 1: Identify host and bacterial factors contributing to attachment and colonization of outbreak-associated Shiga toxin-producing Escherichia coli at gastrointestinal mucosa under various environmental conditions. Sub-objective 1.A: Characterize unique genetic features of outbreak-associated O157 promoting attachment and colonization in food animals. Sub-objective 1.B1: Ascertain the impact of stress conditions on O157 to identify factors impacting virulence gene expression. Sub-objective 1.B2. Ascertain impact of stress on host cells and local microbiota affecting O157 colonization at the rectoanal junction. Objective 2: Develop novel non-antibiotic intervention strategies to limit Shiga toxin-producing E. coli colonization, persistence and/or shedding from food animals. Sub-objective 2.A: Identify novel E. coli with encoded bacteriocins, or competitive nutritional networks that interfere with O157 viability, growth, or attachment to food animal intestinal mucosa. Sub-objective 2.B: Evaluate efficacy of host and/or bacterial proteins to limit O157 mucosal attachment or colonization. Objective 3: Identify intervention strategies to mitigate stress-induced dysbiosis, improve mucosal immunity, and minimize antimicrobial resistance gene transfer from food animal commensals to human pathogens. Sub-objective 3.A: Define changes in host intestinal immune status, intestinal bacterial membership and function, and AMR mobile elements associated with weaning stress. Sub-objective 3.B: Identify non-antibiotic intervention strategies to minimize negative impact on gut dysbiosis and antimicrobial resistance gene transmission to human pathogens.

The goal of this project is to research practical solutions for food safety problems important to food production and public health sectors in the United States and globally. The research addresses food safety at the first link in the food production chain, namely the food animals on the farm. The research investigates the bacterial communities and the animal’s physiological response in the intestinal tract, as well as the interactions between microbiota and intestinal cells that lead to colonization with foodborne organisms and mobility of antimicrobial resistance genes into foodborne pathogens. Some microbiota members confer benefits to the host. Still others are benign to the animal but are harmful foodborne pathogens. The gut microbial consortium comprises a reservoir of antibiotic resistance genes of undefined composition and risk potential. Environmental factors, particularly stress, can modulate both host and bacteria, impacting the symbiotic relationship. Experiments are planned to: 1) examine the environmental, bacterial, and immunological factors affecting Shiga toxin-producing Escherichia coli (STEC) colonization of cattle; 2) identify unique genetic features of STEC impacting colonization and attachment; 3) define the impact of stress on bacterial and immunological events impacting bacterial colonization and antibiotic resistance gene transfer; and 4) examine novel, intervention strategies to reduce foodborne pathogen carriage and antibiotic resistance gene transfer in food animals. The combination of basic and applied research will supply knowledge and tools, as well as applicable strategies to control foodborne pathogens and antibiotic resistance gene mobility.