摘要

       抗生素在人类和兽医学中的广泛使用及其随后释放到环境中可能对本地细菌群落，尤其是淡水生态系统中的细菌群落产生直接影响。在小溪流和河流中，污水处理厂 (WWTP) 的本地输入可能成为有机物、营养物质和新出现的污染物（如抗生素抗性基因 (ARG)）的重要来源。在这项研究中，我们评估了污水处理厂出水作为河流生物膜中 ARGs 来源的影响。在生物膜样本中使用定量 PCR (qPCR) 确定了对主要抗生素家族具有抗性的基因的流行，例如 β-内酰胺类 (blaCTX-M)、氟喹诺酮类 (qnrS)、磺胺类 (sul I) 和大环内酯类 (ermB)收集了四个低阶流中的上游和下游污水处理厂排放点。我们的研究结果表明，污水处理厂出水极大地改变了接收流的水文、物理化学和生物学特性，并有利于底栖微生物群落中抗生素耐药性的持续和传播。还表明，影响的大小取决于每个污水处理厂对接收系统的相对贡献。具体而言，在污水处理厂上游的地点检测到低浓度的 ARG，而在污水处理厂排放点下游收集的生物膜（特别是 ermB 和 sul I 基因）中观察到它们的浓度显着增加。这些发现表明，污水处理厂的排放可能有利于河床生物膜中抗生素耐药性的增加和扩散。本研究还表明，生物膜中 ARG 的存在在污水处理厂排放的下游（最远 1 公里）处很明显。因此，可以合理地假设生物膜可能代表了抗生素耐药性决定因素的获得和传播的理想环境，因此被认为是活性药物化合物人为污染的合适生物指标。

       The extensive use of antibiotics in human and veterinary medicine and their subsequent release into the environment may have direct consequences for autochthonous bacterial communities, especially in freshwater ecosystems. In small streams and rivers, local inputs of wastewater treatment plants (WWTPs) may become important sources of organic matter, nutrients and emerging pollutants, such as antibiotic resistance genes (ARGs). In this study, we evaluated the effect of WWTP effluents as a source of ARGs in river biofilms. The prevalence of genes conferring resistance to main antibiotic families, such as beta-lactams (blaCTX-M), fluoroquinolones (qnrS), sulfonamides (sul I), and macrolides (ermB), was determined using quantitative PCR (qPCR) in biofilm samples collected upstream and downstream WWTPs discharge points in four low-order streams. Our results showed that the WWTP effluents strongly modified the hydrology, physico-chemistry and biological characteristics of the receiving streams and favoured the persistence and spread of antibiotic resistance in microbial benthic communities. It was also shown that the magnitude of effects depended on the relative contribution of each WWTP to the receiving system. Specifically, low concentrations of ARGs were detected at sites located upstream of the WWTPs, while a significant increase of their concentrations was observed in biofilms collected downstream of the WWTP discharge points (particularly ermB and sul I genes). These findings suggest that WWTP discharges may favour the increase and spread of antibiotic resistance among streambed biofilms. The present study also showed that the presence of ARGs in biofilms was noticeable far downstream of the WWTP discharge (up to 1 km). It is therefore reasonable to assume that biofilms may represent an ideal setting for the acquisition and spread of antibiotic resistance determinants and thus be considered suitable biological indicators of anthropogenic pollution by active pharmaceutical compounds.

https://www.sciencedirect.com/science/article/abs/pii/S0269749115301950