Influence of antimicrobial consumption (AMC) on the detection of antimicrobial resistance genes (ARGs) in urban wastewater.
BACKGROUND: Antimicrobial resistance (AMR) is a global health threat, causing over 1.27 million deaths annually and linked to an additional 4.95 million. AMR transmission occurs beyond clinical settings, with wastewater serving as a sentinel of community-level spread. This study investigated how temporal changes in antimicrobial consumption (AMC) correlate with the prevalence of antimicrobial resistance genes (ARGs) in wastewater, using wastewater surveillance (WS) to monitor resistance trends in Quebec, Canada. METHODOLOGY: AMC data (January 2019-May 2023) were obtained from the Institut National de Santé Publique du Québec (INSPQ) under a license from IQVIA Solutions Canada Inc. Wastewater samples (September 2020-September 2022) were obtained from three WWTPs and screened for 11 ARGs, including blaTEM, blaSHV, blaCTX-M, blaNDM, blaOXA-1/30, qnrA, qnrB, mphE, and mefA. Analyses assessed temporal and spatial associations between AMC and ARGs. RESULTS: Total prescriptions declined from 537 to 392 per 1000 inhabitants between 2019 and 2020 (-27 %), likely due to the impact of the COVID-19 pandemic. This shift created a contrast that allowed us to better capture the signal of AMC through the noise in wastewater composition. β-lactams, macrolides, and fluoroquinolones were the most prescribed classes. ARGs were consistently detected in all 41 samples, with macrolide resistance genes being the most abundant. Strong correlations were observed between AMC and ARG prevalence in wastewater, particularly for β-lactams and fluoroquinolones (Spearman R = 0.80 and 0.81, p < 0.05). Spatial patterns showed uniform AMC but variable ARG levels. CONCLUSIONS: Our study highlights the correlation between AMC and ARG. WS shows promise for real-time AMR monitoring.