摘要

    在城市水生态系统中，抗生素抗性基因（ARGs）的发生，传播和组装过程尚不清楚。在这里，我们通过高通量定量PCR研究了中国沿海城市污水处理厂的景观水塘，饮用水水库，进水（IFs）和出水（EFs）等城市水生态系统中ARG的多样性和丰度。总共鉴定出237个ARG，其中多药，氨基糖苷和β-内酰胺酶耐药基因最丰富。城市池塘具有相对较高的多样性，并且与IF和EF共享大量的ARG。池塘中ARGs（1.38×107拷贝/ mL）和流动遗传元素（MGEs）（4.19×106拷贝/ mL）的平均绝对丰度仅比IFs低一个数量级，但比EFs和EFs高一个数量级。水库。由于MGE引起的随机水平基因转移，随机过程在IF和池塘的ARG群落中占主导地位。这些结果表明，城市池塘是ARGs的热点。我们进一步确定了25、3和11个指示剂ARG，分别用于追踪IF，EF和池塘中的ARG污染。我们的研究首次强调了城市池塘在ARGs传播中的作用。

    The occurrence, dissemination and assembly processes of antibiotic resistance genes (ARGs) in urban water ecosystems are far from being understood. Here, we examined the diversity and abundance of ARGs in urban water ecosystems including landscape ponds, drinking water reservoirs, influents (IFs) and effluents (EFs) of wastewater treatment plants of a coastal city, China through high-throughput quantitative PCR. A total of 237 ARGs were identified, where multidrug, aminoglycoside and beta-lactamase resistance genes were the most abundant. Urban ponds had a comparatively high diversity and large numbers of shared ARGs with IFs and EFs. The average absolute abundance of ARGs (1.38 × 107 copies/mL) and mobile genetic elements (MGEs) (4.19 × 106 copies/mL) in ponds were only one order of magnitude lower than those of IFs, but higher than those of EFs and reservoirs. Stochastic processes dominated the ARG community assembly in IFs and ponds due to the random horizontal gene transfer caused by MGEs. These results imply that urban ponds are hotspots of ARGs. We further identified 25, 3, and 11 indicator ARGs for tracing the ARG contamination from IFs, EFs and ponds, respectively. Our study represents the first to highlight the role of urban ponds in the dissemination of ARGs.

    https://www.sciencedirect.com/science/article/abs/pii/S0304389420319981