摘要

    高浓度和亚抑制浓度的水生环境中的抗生素可能会选择抗生素抗性基因（ARG）的进化，对水生生态安全构成潜在风险。我们对天然水沉淀系统中抗生素选择压力下的ARGs和细菌群落的时间和连续动态的了解是有限的。这项研究使用了120天的水动力模型，研究了水沉积系统中ARGs的时间动态，以及14种常用抗生素的衰减和运输后的主要选择性机制。在抗生素的选择性压力下，ARGs瞬时传播，并在去除抗生素后持续存在。细菌群落结构也发生了变化。壁炉架测试和网络分析表明，ARG与水和表面沉积物中的细菌群落显着相关。结构方程模型（SEM）进一步揭示了ARGs的进化主要是由于细菌群落的变化和通过1类整合素整合酶基因（intI1）引起的水平基因转移（HGT）的直接影响，但是抗生素间接影响了ARGs个人资料。 ARGs在深层沉积物中的迁移与细菌群落和intI1无关，但可以通过抗生素的选择性作用和ARG的转化来解释。

    Antibiotics in aquatic environments at high concentrations and sub-inhibitory concentrations potentially select for the evolution of antibiotic resistant genes (ARGs), posing a potential risk to aquatic ecological safety. Our knowledge of the temporal and successive dynamics of ARGs and bacterial community under the selective pressure of antibiotics in natural water-sediment system was limited. This study used a 120-d operating hydrodynamic mesocosm to explore the temporal dynamics of ARGs in water-sediment systems, and the main selective mechanisms following the attenuation and transport of 14 commonly used antibiotics. Under the selective pressures by antibiotics, ARGs propagated transiently, and persisted after antibiotic removal; the bacterial community structures likewise changed. Mantel test and network analysis indicated that ARGs significantly correlated with the bacterial community in the water and surface sediments. Structural equation model (SEM) further revealed that the evolution of ARGs was mainly due to the direct effect of the change in bacterial community and horizontal gene transfer (HGT) via the class 1 integron-integrase gene (intI1), but antibiotics indirectly influenced ARG profiles. The migration of ARGs in deep layer sediments was not related to the bacterial community and intI1, but may be explained by antibiotic selective effects and ARG transformation.

    https://www.sciencedirect.com/science/article/pii/S0160412019343661