Environmental Biofilms Drive Antimicrobial Resistance Amplification: A One Health Perspective

Environmental and surface-associated biofilms function as persistent reservoirs and amplification hubs of antimicrobial resistance (AMR) across agricultural, industrial, and clinical ecosystems. Their ability to colonize diverse substrates including pipelines, filtration membranes, irrigation systems, medical devices, and natural aquatic interfaces confers structural and functional stability that enhances microbial survival and accelerates the dissemination of resistance. Biofilm architecture restricts antimicrobial penetration, supports metabolic heterogeneity, and promotes the formation of persister cells, while quorum-regulated efflux activity and high-frequency horizontal gene transfer further intensify resistance acquisition. As a result, biofilms act not merely as passive repositories of resistant organisms, but as active ecological drivers that sustain AMR across the One Health continuum. This review synthesizes the mechanistic basis of biofilm-mediated tolerance in relation to environment-to-human transmission pathways, emphasizing wastewater infrastructure, livestock production, food processing environments, and built surfaces as critical pathways for circulation. Emerging mitigation strategies, including bacteriophage therapy, CRISPR-based antimicrobials, quorum-sensing inhibitors, antimicrobial peptides, and matrix-degrading enzymes, are evaluated alongside translational constraints such as assay variability and regulatory challenges. By integrating molecular mechanisms with applied system-level interventions, this review outlines a coordinated research and policy framework to mitigate biofilm-driven AMR at its environmental and ecological sources.