Characterization of antimicrobial resistant (AMR) Salmonella enterica isolates associated with cattle at harvest in Mexico.

Antimicrobial resistance is worldwide problem, with severe implications for developing countries, where the higher burden of infectious diseases must co-occur with the rapid emergence and spread of antimicrobial resistance. Furthermore, there are an increasing number of reports of multidrug-resistant foodborne Salmonella enterica infections in both developed and developing countries. Several Salmonella cases have been linked to consumption of food products derived from animals such as beef, poultry, and pig, thus providing evidence this bacterial pathogen can spread from its animal reservoirs to contaminate the human food supply. Therefore, a thorough effort in surveillance is necessary in order to minimize the negative effects of antimicrobial resistance on public health globally. This dissertation outlines the research conducted in order to achieve two objectives: 1) to determine the antimicrobial resistance profiles of 351 Salmonella enterica isolates recovered from cattle feces, hides, and carcasses in three Mexican abattoirs 2) to genomically characterize by Whole Genome Sequencing 25 Salmonella enterica isolates associated with cattle at harvest in Mexico, in order to investigate the differences in antimicrobial gene presence among these isolates and to determine their relationship to each other.