Distribution and community structure of antibiotic resistance genes in the Three Gorges Reservoir Area.

Abstract

Antibiotic resistance genes (ARG) are widespread across various regions. While several studies have investigated the distribution of antibiotic resistance in natural environments, the occurrence and diversity of ARGs in the Three Gorges Reservoir have not been fully elucidated. In this study, we employed metagenomic sequencing techniques to investigate the abundance, diversity, and influencing factors of ARGs in the ecosystem of the Three Gorges Reservoir. A total of 874 ARGs, 20 antibiotic classes, and 6 resistance mechanisms were detected. The dominant ARG is the macB, the dominant antibiotic class is multidrug resistance (MDR), and the dominant resistance mechanism is antibiotic efflux. The microorganisms with the highest contribution to ARGs are Betaproteobacteria and Gammaproteobacteria. In this region, pH and NH4+ concentration were significantly negatively correlated with the relative abundance of most ARGs, while NO3- concentration and TN were significantly positively correlated with the relative abundance of most ARGs. The results indicate that the Three Gorges Reservoir constitutes a significant reservoir of ARGs. By studying the distribution of ARGs in the sediments of the Three Gorges Reservoir Area and the relationship between environmental factors and ARGs, we can more comprehensively understand the pollution status of ARGs in this area, and provide theoretical support for subsequent treatment.