Epidemiology of Campylobacter, Salmonella, and antimicrobial resistant E. coli among free-living Canada geese in southern Ontario
This thesis investigated the role of Canada geese as carriers of pathogenic and resistant bacteria in southern Ontario, using samples collected from three sources: hunted birds, diagnostic specimens, and live birds. Based on multi-level logistic regression models, the prevalence of Campylobacter was significantly lower during the nesting period when birds are nonvolant, suggesting that bird mobility outside of the breeding season impacts the carriage of these microorganisms. Antimicrobial resistance in E. coli was significantly associated with source, which suggests the local environment may be an important source of resistant bacteria. Examination of E. coli resistance patterns and Campylobacter subtypes (based on comparative genomic fingerprinting using a 40-gene assay) in different flocks of geese revealed similar resistance profiles and molecular subtypes in birds of the same flock. Canada geese may be a source of these microorganisms, and have the potential to disseminate them in the environment due to their migratory nature.