摘要

    河流是抗生素抗性基因（ARG）的重要储藏地，但对河流ARG的生物地理模式及其潜在驱动力仍然知之甚少。在这里，我们使用宏基因组学方法来研究两个相邻子流域中ARG的时空变化。中国的北河（NR）和西河（WR）。结果表明杆菌肽（占总ARG的22.8％），多药（占20.7％），磺酰胺（15.2％）和四环素（占10.9％）是主要的ARG类型。 SourceTracker分析表明，污水处理厂是ARGs的主要来源，而动物粪便主要是在NR上游传播ARGs的原因。森林和网络的随机分析证实，NR受到粪便污染的影响。 PCoA分析表明，人为诱发因素的组成随人为梯度的变化而变化，而Raup-Crick无效模型表明，由1类整合子intI1介导的均质选择会在整个分水岭范围内产生稳定的ARG群落。结构方程模型表明，微生物群落，草地和几种非抗生素类微污染物也可能在影响ARGs的分布中发挥某些作用。总体而言，在河流系统中观察到的确定性ARG的形成要求采取有效的管理策略，以减轻抗生素耐药性对公共卫生的风险。

   Rivers are a significant reservoir of antibiotic resistance genes (ARGs), yet the biogeographic pattern of riverine ARGs and its underlying driving forces remain poorly understood. Here, we used metagenomic approach to investigate the spatio-temporal variation of ARGs in two adjacent sub-watersheds viz. North River (NR) and West River (WR), China. The results demonstrated that Bacitracin (22.8 % of the total ARGs), multidrug (20.7 %), sulfonamide (15.2 %) and tetracycline (10.9 %) were the dominant ARG types. SourceTracker analysis indicated that sewage treatment plants as the main source of ARGs, while animal feces mainly contributed in spreading the ARGs in the upstream of NR. Random forest and network analyses confirmed that NR was under the influence of fecal pollution. PCoA analysis demonstrated that the composition of ARGs changed along with the anthropogenic gradients, while the Raup–Crick null model showed that homogenizing selection mediated by class 1 integron intI1 resulted in stable ARG communities at whole watershed scale. Structural equation models revealed that microbial community, grassland and several non-antibiotic micropollutants may also play certain roles in influencing the distribution of ARGs. Overall, the observed deterministic formation of ARGs in riverine systems calls effective management strategies to mitigate the risks of antibiotic resistance on public health.

    https://www.sciencedirect.com/science/article/abs/pii/S0304389420308098