Antibiotic resistance genes in multi-matrices of Chaohu Lake: Spatiotemporal variation and correlation with pesticides and PPCPs.

This study explored the spatiotemporal distributions of microorganisms and antibiotic resistance genes (ARGs) in the surface water, sediments, and fish intestinal contents (IC) of Chaohu Lake, and further revealed the pharmaceuticals and personal care products (PPCPs), pesticides in lake water and their relationships with ARGs. 53 types of pesticides and 25 types of PPCPs were identified in the river-lake system basin, with the highest concentrations observed for tebuconazole (1142.36 ng/L) and amantadine (851.41 ng/L). Higher concentrations of these target contaminants were detected in the western part of the lake and during the wet season. No significant east-west differences in ARGs and microbiota across the three environmental matrices were found, whereas seasonal variations impacted lake water and IC more profoundly than sediments. Significant correlations between microbiota and ARGs in the lake water and IC, while those in sediments showed weaker associations. Co-occurrence network analysis showed, among three environmental media, β-lactam and multidrug-resistant genes were widespread found, and Proteobacteria were identified as a stable host. Non-antibiotic pollutants, such as amantadine and terbuthylazine, displayed significant positive correlations with ARGs, similar to sulfamethoxazole and clindamycin. Our findings highlight the important roles of seasonal hydrological changes and non-antibiotic pollutants in the dissemination of ARGs.