Antimicrobial Resistance and Ecology of Zoonotic Foodborne Pathogens in Dairy Cattle

<p>Objective 1: Examine the relationship between gut bacteria and the bovine host to determine factors that contribute to observed age-related differences in colonization by AMR bacteria. 1A: Determine the capacity of resistant E. coli strains to bind or attach to intestinal epithelial cells. 1B: Evaluate and compare the growth rates of resistant E. coli strains in media that is supplemented with bovine colostrum or milk replacer. 1C: Examine the developing microbial community structure in the young calf intestine and the ability of resistant E. coli strains to outcompete other strains/species in these communities. Objective 2: Examine and determine if resistance determinants in bacteria are linked to specific genomic characteristics that influence bacterial colonization capacity in the young dairy calf. 2A: Identify non-resistance conferring genomic features in calf-associated MDR E. coli that facilitate the colonization of the gut of newborn calves. 2B: Examine the ability of generic, susceptible E. coli strains to outcompete MDR E. coli strains in the gut of newborn calves. Objective 3: Compare and contrast interactions between bovine host cells and Salmonella enterica to identify factors that contribute to differences between Salmonella serotypes that behave as commensal inhabitants of the dairy cow gut and serotypes that are transient in the cow or cause systemic infections.</p>