Abstract
Antibiotic resistance genes (ARGs) are emerging as significant environmental contaminants, posing potential health risks worldwide. Intensive livestock farming, particularly swine production, is a primary contributor to the escalation of ARG pollution. In this study, we employed metagenomic sequencing and quantitative polymerase chain reaction to analyze the composition of microorganisms and ARGs across four vectors in a typical swine fattening facility: dung, soil, airborne particulate matter (PM), and fodder. Surprisingly, soil and PM harbored a higher abundance of microorganisms and ARGs than dung. At the same time, fodder was more likely to carry eukaryotes. Proteobacteria exhibited the highest propensity for carrying ARGs, with proportions 9-20 times greater than other microorganisms. Furthermore, a strong interrelation among various ARGs was observed, suggesting the potential for cooperative transmission mechanisms. These findings underscore the importance of recognizing soil and PM as significant reservoirs of ARGs in swine facilities alongside dung. Consequently, targeted measures should be implemented to mitigate their proliferation, mainly focusing on airborne PM, which can rapidly disseminate via air currents. Proteobacteria, given their remarkable carrying capacity for ARGs with the primary resistance mechanism of efflux, represent a promising avenue for developing novel control strategies against antibiotic resistance.