摘要
      随着人们对抗生素耐药性的日益担忧，追踪城市水道中的抗生素耐药性基因（ARGs）将有助于我们进一步了解城市化对ARGs传播的影响。在目前的研究中，我们评估了九龙江流域250公里处水样中的ARGs谱和抗生素耐药性，以更好地了解人类活动的影响。在21个采样点共检测到244个ARG和12个MGE。观察到的抗性的相对丰度和绝对丰度都随着与城市地区距离的增加而降低。普通最小二乘回归表明，相对和绝对抗性丰度与城市规模呈正相关。耐药组有几个输入和输出，快速预期最大化微生物源追踪（FEAST）表明，大多数抗生素耐药组来源于人类活动。共有8个ARG和20个微生物OTU被认为是区分采样点位置的生物标志物。根据Procrustes分析和Mantel测试，细菌群落与ARGs显著相关，这也得到了共生网络的支持。变异划分分析表明，ARG剖面是由多种因素驱动的。尽管城市群附近的抗生素耐药性丰度显著增加，但随着河流向下游流动，总体耐药性丰度下降。我们的研究强调了城市群规模对流域内抗生素耐药性的影响，以及河流从ARGs污染中恢复的潜在弹性。
Abstract
With growing concerns about antibiotic resistance, the tracking of antibiotic resistance genes (ARGs) in urban waterways will facilitate our increased understanding of the impact of urbanization on ARGs dissemination. In the current study, we assessed the ARGs profiles and antibiotic resistome in water samples along the Jiulong River basin, a distance of 250 km, to better understand the impact of anthropogenic activities. A total of 244 ARGs and 12 MGEs were detected from 21 sampling sites. Both relative and absolute abundance of the observed resistome decreased with increasing distance from urban areas. Ordinary least-squares (OLS) regression revealed that both the relative and absolute resistome abundance were positively correlated with city size. The resistome had several inputs and outputs and Fast Expectation Maximization Microbial Source Tracking (FEAST), suggested that the majority of the antibiotic resistome originated from anthropogenic activities. A total of 8 ARGs and 20 microbial OTUs were considered as biomarkers that differentiated the location of sampling sites. Bacterial communities were significantly correlated with ARGs according to Procrustes analysis and Mantel test, which was also supported by a co-occurrence network. Variation partitioning analysis revealed that ARG profiles were driven by multiple factors. Although antibiotic resistome abundance significantly increased near urban conurbations, overall resistome abundance decreased as the river flowed downstream. Our study highlights the effect of conurbation size on antibiotic resistance profiles within the river basin and the potential resilience of rivers to recover from ARGs contamination.

https://www.sciencedirect.com/science/article/abs/pii/S0048969722009147