Investigating the Role of the Environment on Antimicrobial Resistance in Canada

Abstract

Antimicrobial resistance (AMR) is a complex global challenge affecting human and animal health. This thesis applied multiple analytical approaches to explore the role of the environment in AMR dissemination across Canada. A scoping review identified water and soil as major AMR transmission pathways studied and revealed gaps in AMR studies related to air. Using factor analysis of mixed data and hierarchical clustering on data from the scoping review and 2 other data sources (the Canadian Integrated Program for Antimicrobial Resistance Surveillance and the Antimicrobial Resistance Genes in Bioaerosols Project), this work revealed similar AMR profiles across livestock farms and other environmental settings. Additionally, source attribution models using both frequentist and Bayesian approaches, identified chicken and pig farms as major contributors of AMR subtypes to other animal production systems and environmental settings. Finally, an integrated assessment model was used to integrate and analyze AMR proportions across environmental and agricultural sources. This model suggests that interventions targeting a single source result in limited reductions in overall AMR exposure, whereas coordinated reductions across multiple sources lead to substantially greater decreases in human exposure to AMR. Collectively, these findings demonstrate that AMR cannot be effectively understood or mitigated by examining individual sectors in isolation. Instead, the results underscore the importance of integrated, multi-sectoral strategies that explicitly include environmental pathways alongside animal production systems. This thesis provides a methodological framework for integrating heterogeneous data sources to inform coordinated AMR mitigation strategies through a One Health approach