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ARS Home » Southeast Area » Mississippi State, Mississippi » Poultry Research » Research » Research Project #434880

Research Project: Systems Approach to Understanding and Mitigating Avian Escherichia coli Infections and Antimicrobial Resistance in the Poultry Environment

Location: Poultry Research

2020 Annual Report

1. Use proteomics, genomics, and systems biology approaches to identify molecular determinants of pathogenesis, strain variation, and tissue tropism of different Escherichia (E.) coli strains. 2. Identify immunological targets that will confer cross-protection against prevalent E. coli strains in poultry production and develop vaccine platforms that are effective in very young birds, provide cross-protection, and can be easily administered. 3. Develop systems-level capabilities to evaluate the effects of commercial-scale, poultry management practices on animal health and production; microbial ecology, development of antimicrobial resistance and bacterial pathogen transmission to develop mitigation strategies.

Escherichia (E.) coli is a bacterium that commonly inhabits the gastro-intestinal tract of most animals including poultry. While most strains are nonpathogenic, virulent E. coli strains are often associated with disease in poultry (e.g. colibacillosis) and result in significant economic losses to the poultry industry. To combat E. coli-associated disease in poultry, genotypic and phenotypic traits of virulent E. coli isolates associated with previous colibacillosis outbreaks in chickens will be characterized. The knowledge derived from isolate comparisons will be applied to characterization of E. coli-associated disease as well as to the development of a novel and effective vaccine. Further, vaccination platforms will be developed to maximize the delivery of commercially-available and research derived-vaccines. Application techniques to be investigated will include the traditional means of vaccine delivery including spray, drinking water, and eye-drop. However, novel delivery techniques such as in ovo injections will also be assessed for efficient vaccine delivery. In addition, investigations will be performed to determine the impact of poultry management practices on mitigation of E. coli-related disease. Areas of mitigation interest will include practices to limit E. coli transmission rates and the survivability/maintenance of the pathogen within the poultry environment. The impact of dietary additives including prebiotics, probiotics and bacteriophage will also be considered as means to limit the occurrence of E. coli-related disease in poultry.

Progress Report
To date, approximately 140 Escherichia coli (E. coli) strains derived from infected poultry species have been isolated and stocked in the laboratory for genetic analyses. To develop and test DNA analytic protocols, the nucleic acid sequences of 10 individual E. coli strains were determined and analyses were initiated. Sequence comparisons showed that although the 10 strains shared significant sequence homology, each was a unique isolate. Differentiating areas of sequence included those encoding for genes previously identified as related to the pathogenic nature of the E. coli strains also termed virulence factors. Comparative analyses also identified distinction in the number and size of extrachromosomal sequences associated with each strain. Further, each individual strain was shown to contain between 50 and 65 antibiotic resistance genes with no consistency between the strains as to which genes are present. Due to COVID-19 concerns, all research involving live animals and multiple personnel has been delayed. However, through cooperation with a large animal health company, equipment from them has been installed at our facility for facilitate research upon reopening of the research facilities.