The Role of the Environmental Microbiome in Modulating the Spread of Antimicrobial Resistance.

Antimicrobial resistance (AMR) poses an escalating global health challenge with important environmental dimensions. While the environment is well known as a reservoir and conduit for antibiotic resistance genes (ARGs), the regulatory role of environmental microbiomes in modulating ARG dissemination remains inadequately studied. This review synthesizes current knowledge on how environmental microbiomes influence the spread of AMR by acting as buffers, amplifiers, or gatekeepers of ARG flow in natural and human-impacted ecosystems. We synthesize findings from metagenomic analyses, ecological experiments, and theoretical frameworks to evaluate how microbial diversity, community composition, and ecological interactions shape the persistence and horizontal transfer of ARGs in the environment. Evidence suggests that diverse and resilient microbial communities can inhibit ARG persistence and limit gene transfer, whereas environmental disturbances and biodiversity loss may facilitate ARG propagation. These dynamics highlight the importance of microbial ecosystem structure in shaping AMR trajectories. Understanding the ecological role of environmental microbiomes in AMR dissemination offers new perspectives for antimicrobial stewardship within the One Health framework. Integrating this knowledge into practical interventions, such as engineered microbial consortia and bioremediation can help manage environmental sources of resistance and strengthen global efforts against AMR.