Bacteriophages in the environmental control of antimicrobial resistance: opportunities, risks, and surveillance...

Antimicrobial resistance (AMR) is a major global public health challenge, driven by the persistence and dissemination of antibiotic-resistant bacteria and antibiotic resistance genes (ARGs). These resistance determinants can accumulate and spread across diverse environmental compartments, including wastewater, hospital effluents, agricultural systems, and landfills, facilitating their dissemination through mechanisms such as horizontal gene transfer. Bacteriophages have emerged as promising tools for the targeted control of antibiotic-resistant bacterial populations, as their lytic activity can overcome conventional antibiotic resistance mechanisms and effectively target multidrug-resistant (MDR) and extensively drug-resistant (XDR) bacteria. In addition, phage-encoded enzymes, including endolysins and polysaccharide depolymerases, can disrupt bacterial cell structures and biofilms, further enhancing their potential as alternative antimicrobial strategies. However, the role of bacteriophages in AMR dynamics is inherently dual, as lytic phages can reduce antibiotic-resistant bacterial populations, whereas temperate phages may contribute to the dissemination of ARGs through transduction-mediated gene transfer. This duality represents an important biosafety concern that requires rigorous assessment before their large-scale application in environmental settings. This review critically examines the role of bacteriophages in addressing environmental antimicrobial resistance within a One Health framework. It first explores environmental ARG reservoirs and current surveillance approaches, followed by bacteriophage biology and mechanisms of action, their applications in clinical medicine, veterinary science, and environmental biocontrol, and finally the biological constraints and strategies to address these challenges. This work integrates environmental surveillance with phage-based intervention strategies to support the rational and responsible deployment of bacteriophages as complementary tools in the global response to AMR.