Antibiotic resistance genes (ARGs) and their associated environmental factors in the Yangtze Estuary, China: From inlet to outlet.

The occurrence of antibiotic resistance genes (ARGs) and their associated environmental factors in estuaries are poorly understood. In this study, we comprehensively analyzed ARGs in both water and sediments from inlet to outlet of the Yangtze Estuary, China. The relative abundances of ARGs were higher in the turbidity maximum zone (TMZ) than other sites, implying that suspended particulate matter (SPM) was the major reservoir for ARGs in water. ARGs showed an increasing trend from inlet to outlet in sediments. Positively correlation between intI1 and sul1 in both water and sediments indicated that sul1 may be regulated by intI1. Correlation analysis and redundancy analysis showed that the spatial variations of estuarine ARGs were positively correlated with sample properties (e.g., temperature, SPM, pH) and chemical pollutants (e.g., heavy metals and antibiotic residues), among which chemical pollutants were the major drivers for the ARG distribution in both water and sediments.