Biofilms and antimicrobial resistance: A hidden driver in the one health AMR crisis

Antimicrobial resistance (AMR) is a grand challenge threatening global health, food systems, and ecosystems. Biofilms— structured microbial communities encased in an extracellular matrix—are a pervasive but underappreciated driver of AMR across the One Health continuum (humans, animals, and the environment). Biofilm physiology elevates antimicrobial tolerance through diffusion barriers, altered microenvironments, stress responses, and persister formation, while promoting horizontal gene transfer (HGT) of resistance determinants. In clinical care, biofilms complicate device-associated infections, chronic wounds, and respiratory disease. In agri-food systems, they colonize farm environments, food processing equipment, and aquaculture infrastructure. In natural and built environments, biofilms act as reservoirs and reactors for resistance genes and antibiotic residues. This review synthesizes current understanding of biofilm-driven AMR across One Health, highlights advance in detection and control, and outlines prioritized policy, surveillance, and research actions to address this hidden driver.