摘要

       污水处理厂 (WWTP) 被认为是抗生素抗性基因 (ARG) 的储存库。细菌系统发育可以塑造活性污泥中的抵抗组。然而，在大陆尺度的不同污水处理厂中，ARGs 丰度和细菌群落的共存和相互作用仍未得到全面了解。在这里，我们应用定量 PCR 和 Miseq 序列方法来揭示 18 个地理分布的污水处理厂中 ARG（sul1、sul2、tetW、tetQ、tetX）、intI1 基因和细菌群落的变化特征。结果表明，sul1和sul2基因的平均相对丰度分别为2.08×10-1和1.32×10-1copies/16S rRNA copy。 tetW 基因的丰度与香农多样性指数（H'）呈正相关，而 sul 基因与 intI1 基因均呈显着正相关。 sul1、sul2、tetX和intI1基因的平均相对丰度最高出现在南部地区和氧化沟系统。网络分析发现16个细菌属与tetW基因共存。共生模式揭示了好氧/缺氧/好氧和氧化沟系统之间不同的群落相互作用。细菌群落组成的冗余分析模型图清楚地表明，来自不同地理区域的污泥样品之间存在显着差异，细菌群落组成的变化与ARGs相关。总之，本研究的这些发现将突出 ARGs 和携带这些 ARGs 的细菌种群的潜在风险，并有助于开发合适的技术来控制 ARGs 从污水处理厂向水生环境的传播。

       Wastewater treatment plants (WWTPs) are deemed reservoirs of antibiotic resistance genes (ARGs). Bacterial phylogeny can shape the resistome in activated sludge. However, the co-occurrence and interaction of ARGs abundance and bacterial communities in different WWTPs located at continental scales are still not comprehensively understood. Here, we applied quantitative PCR and Miseq sequence approaches to unveil the changing profiles of ARGs (sul1, sul2, tetW, tetQ, tetX), intI1 gene, and bacterial communities in 18 geographically distributed WWTPs. The results showed that the average relative abundance of sul1and sul2 genes were 2.08 × 10−1 and 1.32 × 10−1 copies/16S rRNA copies, respectively. The abundance of tetW gene was positively correlated with the Shannon diversity index (H′), while both studied sul genes had significant positive relationship with the intI1gene. The highest average relative abundances of sul1, sul2, tetX, and intI1 genes were found in south region and oxidation ditch system. Network analysis found that 16 bacterial genera co-occurred with tetW gene. Co-occurrence patterns were revealed distinct community interactions between aerobic/anoxic/aerobic and oxidation ditch systems. The redundancy analysis model plot of the bacterial community composition clearly demonstrated that the sludge samples were significant differences among those from the different geographical areas, and the shifts in bacterial community composition were correlated with ARGs. Together, these findings from the present study will highlight the potential risks of ARGs and bacterial populations carrying these ARGs, and enable the development of suitable technique to control the dissemination of ARGs from WWTPs into aquatic environments.

https://www.sciencedirect.com/science/article/abs/pii/S1001074218334521