Antimicrobial use and antimicrobial resistance (AMR) in aquaculture: a One Health evidence-chain review of the “use–environment–food–human” continuum

Background Antimicrobial resistance (AMR) is a major global challenge to public health and sustainable development. Its emergence and spread are shaped by antimicrobial use (AMU) in human healthcare and animal production, including aquaculture, and by environmental pathways. The One Health framework emphasizes the interdependence of human, animal, and ecosystem health and supports integrated assessment of AMR risk and coordinated mitigation. Objective Within a One Health framework, this review synthesizes evidence linking AMU in aquaculture to AMR and maps the transmission continuum from on-farm use → aquatic environments → aquatic products and processing → human exposure and health risks, highlighting actionable mitigation strategies and research priorities. Methods We conducted an evidence-chain systematic mapping review following PRISMA 2020 guidance. PubMed, Web of Science Core Collection, and Scopus were searched, alongside relevant grey literature from WHO, FAO, and WOAH websites, for studies published between 1 January 2000 and 31 January 2026. Eligible records addressed AMU in aquaculture and/or AMR/antimicrobial resistance genes (ARGs) across the use–environment–food–human continuum. Two reviewers independently screened titles/abstracts and full texts using predefined criteria. Study quality was assessed with design-appropriate checklists, and findings were synthesized by production system, environmental compartment, food-chain stage, and human exposure pathway. Results AMU in aquaculture can select for resistant bacteria and enrich ARGs within farms. Resistance determinants may spread to surrounding waters and sediments via effluents, sediment disturbance, and the movement of personnel and equipment. In environmental compartments, co-occurrence of ARGs with mobile genetic elements (MGEs) may facilitate horizontal gene transfer, contributing to an environmental resistome. Aquatic products and processing steps can act as vehicles for resistant bacteria/ARGs, while human exposure may occur through food handling and consumption, occupational contact, and environment-related routes. Conclusion The AMU–AMR nexus in aquaculture shows typical One Health characteristics. Effective governance should combine: (1) reducing unnecessary AMU, (2) strengthening prevention and biosecurity, (3) harmonizing AMU/AMR surveillance, (4) improving effluent and discharge management, and (5) enhancing hygiene along the food chain and risk communication. Future research should prioritize quantitative attribution, standardized cross-sector monitoring, and integrative synthesis linking molecular AMR indicators to human health outcomes.