From Policy to Pathways: A One Health Assessment of Antimicrobial Resistance (AMR) in Wastewater and Surface Waters

Abstract

Antimicrobial resistance (AMR) represents a complex environmental and public health challenge driven by interactions among engineered systems, natural ecosystems, and global antimicrobial use practices. While antimicrobial misuse in clinical and agricultural settings contribute to the evolution of resistance, environmental pathways such as wastewater discharge and watershed processes play a critical role in the dissemination of antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs). We applied a One Health (i.e., humans-animals-environment) framework to assess AMR policies, the extent to which wastewater infrastructure addresses AMR, and AMR inputs to surface waters. Comparative analysis of antibiotic use policies in Nigeria, Germany, and the United States through a comprehensive literature review highlighted how national stewardship strategies and regulatory differences can influence resistance dissemination across socioeconomic contexts. Longitudinal field studies in an urban watershed were conducted to assess the impact of wastewater treatment plant effluent and tributary inputs on shaping microbial communities and antibiotic resistance dynamics. Amplicon sequencing, shotgun metagenomic, and physicochemical measurements were used to characterize microbial community, ARGs, and metal resistance genes (MRGs) across spatial gradients. Treated effluent showed limited impact on downstream microbial communities and resistance gene profiles, highlighting treatment efficiency, whereas tributaries contributed distinct microbial signatures and elevated resistance signals. These findings highlight the need to integrate environmental monitoring, antibiotic stewardship, and infrastructure investment to address AMR while advancing understanding of environmental pathways that influence its dissemination.