Managing environmental antimicrobial resistance (AMR) under climate change: current gaps and future needs.

Climate change-induced environmental alterations are significantly accelerating the development and dissemination of antimicrobial resistance (AMR) in the environment through multiple interconnected pathways. Rising global temperatures facilitate bacterial adaptation and mutation rates, with studies demonstrating that even small temperature increases can enhance bacterial resistance gene stability and horizontal transfer efficiency. Extreme weather events such as flooding and droughts disrupt sanitation infrastructure, leading to increased pathogen transmission and subsequent antimicrobial use, while also creating conditions that promote the mixing of resistant bacteria from different environmental compartments. Climate-induced changes in precipitation patterns and ecosystem disruption further contribute to AMR spread by altering microbial community dynamics and increasing exposure to heavy metals and pollutants that co-select for antibiotic resistance genes. Current management strategies remain fragmented, with the UK's 2024-2029 National Action Plan emphasizing the need for improved waste management, wastewater treatment, and stewardship initiatives to reduce environmental AMR dissemination, though implementation faces significant technical and financial barriers. Critical knowledge gaps persist regarding the quantitative relationships between environmental factors and AMR development, with insufficient surveillance data from environmental matrices, limited understanding of resistance gene transmission pathways, and inadequate standardized methodologies for environmental AMR monitoring. Perhaps most concerning is the lack of comprehensive government policies specifically addressing climate-AMR interactions, with most countries lacking integrated frameworks that connect climate adaptation strategies with AMR mitigation efforts, despite growing recognition that both challenges share common drivers and require coordinated responses under the One Health approach. The absence of robust environmental AMR surveillance systems particularly in low- and middle-income countries creates substantial data gaps that hinder evidence-based policy development, while regulatory frameworks remain primarily focused on clinical settings rather than addressing the broader environmental dimensions of resistance emergence and spread.