Spatiotemporal Variability in Wastewater-Derived Carbapenem-Resistance Genes from Diverse Municipal Sources in the Laurentian Great Lakes Catchment

Abstract Antimicrobial resistance is quickly becoming one of the largest threats facing global health. To combat this threat, surveillance is necessary to understand the presence of potential antimicrobial resistance beyond what is identified in clinical isolates. Using wastewater-based surveillance, we conducted a year long sampling campaign of four critical concern carbapenem-resistance genes at five sites to determine spatiotemporal patterns. Environmental factors were also examined to identify potential influencers of carbapenemase gene concentrations in the wastewater. Non-metric multidimensional scaling (NMDS) revealed that these antimicrobial resistance genes exhibited significant site-specific, but not seasonal, clustering. Further investigation into seasonal variation revealed that gene concentrations were significantly different between season and displayed monotonic changes. The four carbapenemase genes did not exhibit similar trends or concentrations across seasons or treatment plants, but all underwent large day-to-day fluxes. Using distance-based redundancy analysis (dbRDA), environmental factors were able to explain ~ 40% of the variation in gene profiles. However, each gene had differing correlations to all of the environmental factors studied here. These results indicate that a complex matrix of factors influence each antimicrobial resistance gene in a unique way with no consistent spatiotemporal patterns across the carbapenemase gene class.