Background

Aquatic ecosystems are considered to be among the most important reservoirs of antibiotic resistance genes (ARGs). Drinking water sources could serve as critical points of ARGs transfer from environment to human. In this study, the distribution of antibiotics and ARGs across Qingcaosha Reservoir located in the Yangtze River Delta during three seasons was investigated to characterize the pollution patterns.

Results

Sulfamethoxazole, sulfamonomethoxine and penicillin G potassium salt were the dominant antibiotics in this reservoir. Sulfonamide resistance genes (sul1 and sul2) were the most prevalent and predominant genes. Higher total relative abundance of the ARGs was detected in the site closest to the inflow than those in other sites. Overall, the concentrations of antibiotics in May were relatively lower than those in November and February. Correlation analysis indicated sul1, ermB and mphA had positive correlation with corresponding antibiotics in February and sul1, sul2, ermB and mphA was also positively correlated to intI1.

Conclusion

In conclusion, antibiotics and ARGs were widespread in Qingcaosha Reservoir. Our results indicated that the drinking water reservoir might serve as gene reservoir for antibiotic resistance and mobile gene element intI1 can serve as a medium to contribute to the widespread of various ARGs. As the ARGs abundance was found to be higher in the inflow of the reservoir compared to the outflow, it is considered that reservoir could serve as a functional area contributing to the elimination or dilution of ARGs.

中文翻译：

---

长江三角洲青草沙水库的抗生素及抗生素抗性基因特征

背景

水生生态系统被认为是最重要的抗生素抗性基因（ARGs）库。饮用水源可以作为ARGs从环境向人类转移的关键点。在本研究中，调查了长江三角洲青草沙水库三个季节中抗生素和ARGs的分布情况，以表征污染模式。

结果

磺胺甲恶唑，磺胺单甲恶灵和青霉素G钾盐是该储层中的主要抗生素。磺酰胺抗性基因（sul1和sul2）是最普遍和最主要的基因。在最靠近流入点的位置检测到的ARG的总相对丰度比其他位置更高。总体而言，5月的抗生素浓度相对低于11月和2月的浓度。相关分析表明，sul1，ermB和mphA与2月份相应的抗生素和sul1，sul2，ermB和mphA呈正相关。也与intI1正相关。

结论

总之，青草沙水库中普遍存在抗生素和ARGs。我们的结果表明，饮用水水库可能是抗药性的基因库，而流动基因元件intI1可以作为促进各种ARGs传播的媒介。由于发现水库流入的ARGs丰度高于流出水，因此认为水库可以充当有助于消除或稀释ARGs的功能区域。