Intracellular and Extracellular Antibiotic Resistance Genes in Airborne PM_2.5 for Respiratory Exposure in Urban Areas

The current research paradigm for the environmental dissemination of antibiotic resistance genes (ARGs) focuses on those harbored within bacteria (i.e., intracellular fraction). Understanding both and extracellular ARGs has particular implications flux fate that are airborne via fine particulate matter (PM2.5) from ambient atmosphere to human airway. In this study, we developed an operationally defined protocol urban PM2.5 quantify abundance occurring in free phage-associated DNA, addition their counterparts commonly analyzed bacterial cells. results demonstrated fraction comprises a significant proportion total PM2.5, with subtype-specific dominance either or DNA. A comparison between temperate subtropical cities revealed geographical disparities PM2.5-associated due influences regional meteorological factors oxidative gases. Considering potential horizontal gene transfers efficiency respiratory deposition, could represent >60% modeled inhalational intake most some cities. This study highlights importance dynamics health across climate zones pollution gradients.