摘要

       随着世界范围内大坝的快速建设，水库系统已成为现代水环境的代表。然而，抗生素抗性基因（ARGs）的概况和影响其在现代水生环境（例如水相、沉积物相和土壤相）中动态的相关因素在很大程度上是未知的。在这里，我们使用高通量定量 PCR 综合表征了大型饮用水水库中 ARGs 的多样性、丰度和分布，并对因素（例如，移动遗传元件 (MGEs)、细菌群落、细菌生物量、抗生素、和基本属性）在结构方程模型（SEM）的基础上影响 ARG 的分布。与沉积物相和土相相比，水相更容易包含更多种类的 ARG，而下降区的土相是 ARG 的潜在储存库和热点。环境介质部分影响了现代水生环境中的 ARG 多样性，同时它明显影响了 ARG 和 MGE 的分布及其共生模式。 ARGs在水相中的增殖和扩散途径为水平基因转移（HGT）和垂直基因转移（VGT），而在沉积相和土壤相中的主要途径分别为HGT和VGT。 SEMs表明MGEs在水相和沉积物相中对驱动ARG动力学的贡献最大，而在土壤相中最主要的因素是细菌群落。总体而言，环境介质可能通过使 MGE、细菌群落、细菌生物量、抗生素和基本特性多样化来推动现代水生环境中 ARGs 的动态变化。

       With the rapid construction of dams worldwide, reservoir system has become a representation of modern aquatic environment. However, the profiles of antibiotic resistance genes (ARGs) and associated factor influencing their dynamics in modern aquatic environment (e.g., water phase, sediment phase, and soil phase) are largely unknown. Here, we comprehensively characterized the diversity, abundance, distribution of ARGs in a large drinking water reservoir using high-throughput quantitative PCR, as well as ranked the factors (e.g., mobile genetic elements (MGEs), bacteria community, bacterial biomass, antibiotics, and basic properties) influencing the profiles of ARGs on the basis of structural equation models (SEMs). Water phase was prone to harbor more diverse ARGs as compared to sediment phase and soil phase, and soil phase in drawdown area was a potential reservoir and hotspot for ARGs. Environmental media partially affected the ARG diversity in modern aquatic environment, while it observably influenced the distributions of ARGs and MGEs and their co-occurrence patterns. The pathways for the proliferation and spread of ARGs in water phase were both the horizontal gene transfer (HGT) and vertical gene transfer (VGT), while the dominant pathways in sediment phase and soil phase were the HGT and VGT, respectively. The SEMs demonstrated that MGEs contributed the most to drive the ARG dynamics in both water phase and sediment phase, while the most dominant factor for this in soil phase was bacterial community. Overall, environmental media exerted a bottleneck in driving the dynamics of ARGs in modern aquatic environment probably via diversifying the MGEs, bacterial community, bacterial biomass, antibiotics and basic properties.

https://www.sciencedirect.com/science/article/abs/pii/S0043135419305603