Air resistome in urban and rural environments – review

The atmosphere serves as a reservoir and transmission pathway for pathogenic microorganisms and antimicrobial resistance genes (ARGs), which can be inhaled or ingested and pose emerging public health risks. Despite growing awareness of antimicrobial resistance in soil and water, the air resistome—the characterization of ARGs in airborne matrices remains relatively understudied. Humans can inhale thousands of resistance genes daily as airborne ARGs occur at 103–105 gene copies/m³ of air. Human population growth and intensive anthropogenic activities have profoundly altered natural ecosystems, reshaping microbial community structures in the atmosphere. Urban and rural environments differ in emission sources, land use, and pollution profiles, necessitating distinct approaches to assess and mitigate their respective air resistome. However, most existing studies emphasize bacterial diversity rather than the occurrence, abundance, and dissemination of ARGs across these environments. Understanding the spatial variability of airborne ARGs is critical for developing early warning systems and informing public health surveillance. This review emphasizes current knowledge on ARG gradients from urban to rural settings, highlights the role of anthropogenic drivers in their distribution, and identifies key knowledge gaps. We advocate for the routine monitoring of biological pollutants, including ARGs, as part of comprehensive air quality management and regulatory frameworks. Finally, integrating One Health approach into policy ensures holistic AMR control across humans, animals, and ecosystem.