Transfer Pathways and Driving Forces of Antibiotic Resistance Genes from Reclaimed Water to Groundwater

The spread of antibiotic resistance genes (ARGs) in urban groundwater caused by reclaimed water infiltration has become a significant environmental risk. According to the spatial and temporal distribution of antibiotics and ARGs, reclaimed water from wastewater treatment plant (WWTP) is a source of antibiotics and ARGs of groundwater. There were different microbial functional group mainly affected by nitrogen and antibiotics in groundwater and reclaimed water. The assembly of groundwater microbial communities in the infiltration area is more affected by deterministic processes than deterministic processes due to contaminations input. According to co-occurrence network analysis, the shared microbiota were identified and considered to be the core genera and host of ARGs for the transport from reclaimed water to groundwater. MacB was possibly the most abundant ARG, which was transferred from reclaimed water to groundwater by Acidovorax, Hydrogenophaga, Methylotenera, Dechloromonas, Nitrospira and so on. In the infiltration process, not only environmental factors but the tradeoff between energy metabolism and antibiotic defense strategy also possibly affected ARG transfer. The transfer pathway and driving forces of ARGs from reclaimed water to groundwater provided a new perspective for evaluating the spread risk of ARGs in water infiltration.