MOLECULAR EPIDEMIOLOGY OF SALMONELLA IN CONVENTIONAL AND ANTIMICROBIAL FREE SWINE PRODUCTION SYSTEMS

Foodborne outbreaks due to antimicrobial resistant Salmonella strains have been reported due to consumption of pork products. The role of unidentified selective pressures that result in persistence of antimicrobial resistant strains in different swine production environments remains to be investigated. The available information on Salmonella dynamics in the conventional system does not apply to the antimicrobial free (ABF) system due to differences in them. The need to conduct a longitudinal based study to determine and compare the risk factors that are responsible for the persistence of Salmonella in these swine production environments is crucial. The long term goal of this longitudinal study is to determine and compare the molecular epidemiology and dynamics of Salmonella in the conventional and the ABF systems. Swine sampling will be done at three stages on farm (farrowing, nursery and finishing). Salmonella isolates will be characterized at the phenotypic and genotypic levels. Pertinent management data will be collected and appropriate epidemiological and statistical analysis will be performed to determine risk factors for Salmonella dissemination in pigs at farm and in these two distinct production systems. Information generated in this study will help us to determine the establishment of Salmonella infection and its dynamics within a herd and to better implement control measures. The proposal is relevant to priorities listed under the Epidemiological Approaches to Food Safety (32.0) with focus on studies to identify new risk factors that affect the prevalence, transmission and persistence of food borne organisms across the farm-to-fork continuum.