摘要

在这项研究中，我们量化了从市政污水处理厂（WWTP）排放点上游和下游收集到Ter River中的11种抗生素化合物和9种抗生素抗性基因（ARG）。通过与质谱联用的液相色谱分析抗生素，然而通过实时PCR确定细菌，噬菌体和质粒DNA组分中ARG的浓度，以探索它们对环境抗生素抗性的贡献。污水处理厂的排放导致在影响点下游收集的水样中含有较高浓度的抗生素残留物和ARGs。具体而言，赋予对大环内酯（ermB），氟喹诺酮（qnrS）和四环素（tetW）的抗性的基因在三个DNA部分（即细菌，质粒和噬菌体）中的上游和下游位点之间显示出显着差异（p <0.05）。有趣的是，赋予对β-内酰胺（blaTEM，blaNDM和blaKPC）和糖肽（vanA）的抗性的基因仅在噬菌体和质粒DNA的上游和下游位点之间显示显着差异（p <0.05），但在细菌DNA部分中不显示。我们的研究结果首次显示了通过污水处理厂排放，暴露于慢性抗生素污染的水生环境中噬菌体和质粒对动员ARGs的贡献程度。因此，这些移动遗传因素应纳入进一步研究中，以全面了解抗生素耐药性的传播。

In this study, we quantified eleven antibiotic compounds and nine antibiotic resistance genes (ARGs) in water samples collected upstream and downstream of the discharge point from a municipal wastewater treatment plant (WWTP) into the Ter River. Antibiotics were analyzed by liquid chromatography coupled to mass spectrometry, whereas the concentration of ARGs in bacterial, phage and plasmid DNA fractions was determined by real-time PCR to explore their contribution to environmental antibiotic resistance. WWTP discharges resulted in higher concentrations of antibiotic residues as well as ARGs in water samples collected downstream the impact point. Specifically, genes conferring resistance to macrolides (ermB), fluoroquinolones (qnrS) and tetracyclines (tetW) showed significant differences (p < 0.05) between upstream and downstream sites in the three DNA fractions (i.e. bacteria, plasmids and phages). Interestingly, genes conferring resistance to β-lactams (blaTEM, blaNDM and blaKPC) and glycopeptides (vanA) only showed significant differences (p < 0.05) between upstream and downstream sites in phage and plasmid DNA but not in the bacterial DNA fraction. Our results show for the first time the extent to which phages and plasmids contribute to the mobilization of ARGs in an aquatic environment exposed to chronic antibiotic pollution via WWTP discharges. Accordingly, these mobile genetic elements should be included in further studies to get a global view of the spread of antibiotic resistance.

https://www.sciencedirect.com/science/article/pii/S0048969717312810