On the Road: Car Cabin Air Filters Reveal Geographic Trends in Antimicrobial Resistance Genes across Canada

PAUL GEORGE, Marc Veillette, Florent Rossi, Amélia Bélanger Cayouette, Samantha Leclerc, Maosheng Yao, Nathalie Turgeon, Caroline Duchaine, Université Laval

     Abstract Number: 152
     Working Group: Bioaerosols

Abstract
Antimicrobial resistant bacteria can spread throughout the wider environment through the air in bioaerosols originating from anthropogenic sources, such as agriculture, wastewater treatment, or hospitals. Upon deposition in a new environment, they may pass antimicrobial resistance genes (ARGs) to other bacteria via horizontal gene transfer. Monitoring the spread of ARGs requires multidisciplinary approaches in a One Health context as understanding the diversity of environmental ARGs and their potential sources is necessary to make actionable policy to combat their spread. Here, we apply a recently developed method using car cabin air filters as monitors of airborne bacteria and ARGs genes across Canada. We collected 477 filters from 51 locations. For each filter, local population, agricultural, and environmental data was collected from publicly available government sources. We developed a bespoke processing methodology to extract dust from filters for DNA extraction. We then quantified copy numbers of 16S and the ARGs using high-throughput qPCR. Bacterial biomass and ARG copy numbers were highest in Ontario and lowest in Canada’s Territories. This is driven by a positive correlation with human population. Quinolones were the most abundance genes across all regions since they are plasmid-associated. Upon their removal, regional trends became clearer. Tetracycline resistance genes showed a strong positive relationship with poultry and pig populations, but also elevation. This may be explained by their natural prevalence in soils as well as their use in agriculture. Sulfonamide, macrolinde, and tetracycline resistance genes were significantly correlated with regional livestock populations, as were mobile genetic elements. Aminoglycoside resistance genes were positively correlated with human populations. ARG richness was highest in Ontario and the prairie provinces and lowest in the Atlantic provinces. 16S sequencing results are incoming and will be presented to complement these findings and further explain the biological reasons behind ARG distributions on the national-scale.