[Distribution Characteristics and Driving Mechanism of Antibiotic Resistance Genes in a Water Source in Hefei, China]

One of the important water sources in Hefei serves as a crucial water supplier, playing a vital role in water provisioning. Its water quality is related to both drinking water safety and ecological water safety. To elucidate the distribution characteristics and influencing factors of antibiotic resistance genes (ARGs) within the water source, water, sediment, and soil samples were collected in July 2021 and December 2021. Metagenomic sequencing was employed to identify and characterize ARGs, mobile genetic elements (MGEs), and bacterial communities in the samples. The correlations between ARGs and physical-chemical properties, antibiotics, MGEs, and bacterial communities were also analyzed. Lastly, the factors were categorized into physical-chemical and biological factors, and their degrees of influence on ARGs were analyzed. The results showed that a total of 544 subtypes of ARGs were detected in the water source, which were classified into 26 major categories. Multidrug, bacitracin, β-lactam, and polymyxin resistance genes were the dominant types of ARGs in all three media, with the subtype bacA exhibiting the highest abundance across all. The numbers of certain classifications of ARGs tended to be higher in soil compared to those in sediment and water, and the abundance of ARGs in the soil was also significantly higher than that in the sediment. PCoA analysis showed significant differences in the structural composition of ARGs among the three media. Correlation analyses showed that TP, pH, LINs, and FQs in the water and SAs in the sediment were significantly correlated with ARGs. Additionally, strong correlations were observed between MGEs and bacterial communities and ARGs in the three media. The VPA results indicated that biological factors played a pivotal role in influencing ARGs in water, whereas physical-chemical factors exerted a stronger influence in soil. However, the synergistic effect of both physical-chemical and biological factors on ARGs in all three media was not negligible.