Wastewater treatment plants (WWTPs) are significant sources of antibiotic resistance genes (ARGs) in aquatic environments. Mobile genetic elements (MGEs) and microbial community are key factors influencing the proliferation of ARGs. To reveal the effects of WWTPs' effluent discharge on ARGs and microbial community in the coastal area, we used high-throughput quantitative PCR and high-throughput sequencing to investigate the distribution of ARGs, MGEs, and microbial community in the effluent receiving areas (ERAs) of two coastal WWTPs, as well as offshore of Hangzhou Bay (HB). Our study revealed that multidrug resistance genes were the most abundant ARGs in all sampling sites. The diversity and abundance of ARGs and MGEs were significantly higher in the ERAs compared to HB. Additionally, the distribution of ARGs, MGEs, and microbial communities between the ERAs and HB was significant different, suggesting that long-term wastewater discharge could alter these distributions in coastal areas. 12 bacterial genera showed strong positive correlations with ARGs and MGEs. Multidrug and β-lactamase resistance genes had the most abundant potential bacterial hosts, while only one MGEs (tnpA-05) showed significant positive correlation with Others bacterial genera.

Coastal area, Wastewater discharge, Antibiotic resistance genes (ARGs), Mobile genetic elements (MGEs), Microbial community