School of Environmental Science and Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, China; School of Environment and Energy Engineering, Anhui Jianzhu University, Hefei, Anhui Province, 230601, China.
Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021, China.
Water Res. 2019 Feb 1;149:179-189. doi: 10.1016/j.watres.2018.11.007. Epub 2018 Nov 8.
The rapid construction of reservoir in river basin generates a river-reservoir system containing an environmental gradient from river system to reservoir system in modern aquatic environment worldwide. Profiles of antibiotic resistance genes (ARGs) in river-reservoir system is essential to better understand their dynamic mechanisms in aquatic eco-environment. In this study, we investigated the diversity, abundance, distribution of ARGs and mobile genetic elements (MGEs) in a representative river-reservoir system using high-throughput quantitative PCR, as well as ranked the factors (e.g. antibiotics, bacterial biomass, bacteria communities, and MGEs) influencing the patterns of ARGs based on structural equation models (SEMs). Seasonal variations in absolute abundance of ARGs and MGEs exhibited similar trends with local rainfall, suggesting that seasonal runoff induced by the rainfall potentially promote the absolute abundance of ARGs and MGEs. In contrast, environmental gradient played more important roles in the detected number, relative abundance, distribution pattern of ARGs and MGEs in the river-reservoir system. Moreover, environmental gradient also made the co-occurrence patterns associated with ARGs subtypes, MGEs and bacteria genera in river system different from those in reservoir system. The SEMs revealed that MGEs contributed the most to shape the ARG profiles. Overall, our findings provide novel insights into the mechanisms of environmental gradient on ARGs dynamics in river-reservoir system, probably via influencing the MGEs, antibiotics, pathogenic bacteria community and nonpathogenic bacteria community.
在全球现代水生环境中，流域内水库的快速建设产生了一种从河流系统到水库系统的环境梯度的河库系统。了解河库系统中抗生素抗性基因（ARGs）的分布特征对于更好地理解其在水生态环境中的动态机制至关重要。在这项研究中，我们使用高通量定量 PCR 技术研究了一个具有代表性的河库系统中 ARGs 和移动遗传元件（MGEs）的多样性、丰度和分布，并基于结构方程模型（SEMs）对影响 ARGs 模式的因素（如抗生素、细菌生物量、细菌群落和 MGEs）进行了排序。ARGs 和 MGEs 的绝对丰度季节性变化与当地降雨量呈现出相似的趋势，表明降雨引起的季节性径流可能会促进 ARGs 和 MGEs 的绝对丰度。相比之下，环境梯度在河库系统中 ARGs 和 MGEs 的检出数量、相对丰度和分布模式方面发挥了更为重要的作用。此外，环境梯度还使河流系统中与 ARGs 亚型、MGEs 和细菌属相关的共现模式与水库系统中的共现模式不同。SEMs 表明，MGEs 对 ARG 谱的形成贡献最大。总的来说，我们的研究结果为环境梯度对河库系统中 ARGs 动态的影响机制提供了新的见解，可能是通过影响 MGEs、抗生素、致病菌群落和非致病菌群落来实现的。
