Department of Biological Sciences, University of Illinois at Chicago, Chicago, Illinois, USA.
Department of Civil and Environmental Engineering, Northwestern University, Evanston, Illinois, USA.
Appl Environ Microbiol. 2018 Feb 14;84(5). doi: 10.1128/AEM.02168-17. Print 2018 Mar 1.
Wastewater treatment plants (WWTPs) release treated effluent containing mobile genetic elements (MGEs), antibiotic resistance genes (ARGs), and microorganisms into the environment, yet little is known about their influence on nearby microbial communities and the retention of these factors in receiving water bodies. Our research aimed to characterize the genes and organisms from two different WWTPs that discharge into Lake Michigan, as well as from surrounding lake sediments to determine the dispersal and fate of these factors with respect to distance from the effluent outfall. Shotgun metagenomics coupled to distance-decay analyses showed a higher abundance of genes identical to those in WWTP effluent genes in sediments closer to outfall sites than in sediments farther away, indicating their possible WWTP origin. We also found genes attributed to organisms, such as those belonging to , , , and , in effluent from both WWTPs and decreasing in abundance in lake sediments with increased distance from WWTPs. Moreover, our results showed that the WWTPs likely influence the ARG composition in lake sediments close to the effluent discharge. Many of these ARGs were located on MGEs in both the effluent and sediment samples, indicating a relatively broad propensity for horizontal gene transfer (HGT). Our approach allowed us to specifically link genes to organisms and their genetic context, providing insight into WWTP impacts on natural microbial communities. Overall, our results suggest a substantial influence of wastewater effluent on gene content and microbial community structure in the sediments of receiving water bodies. Wastewater treatment plants (WWTPs) release their effluent into aquatic environments. Although treated, effluent retains many genes and microorganisms that have the potential to influence the receiving water in ways that are poorly understood. Here, we tracked the genetic footprint, including genes specific to antibiotic resistance and mobile genetic elements and their associated organisms, from WWTPs to lake sediments. Our work is novel in that we used metagenomic data sets to comprehensively evaluate total gene content and the genetic and taxonomic context of specific genes in environmental samples putatively impacted by WWTP inputs. Based on two different WWTPs with different treatment processes, our findings point to an influence of WWTPs on the presence, abundance, and composition of these factors in the environment.
污水处理厂（WWTP）将含有移动遗传元件（MGEs）、抗生素抗性基因（ARGs）和微生物的处理后的废水排放到环境中，但人们对它们对附近微生物群落的影响以及这些因素在受纳水体中的保留情况知之甚少。我们的研究旨在描述从排入密歇根湖的两个不同 WWTP 以及周围湖底沉积物中分离出的基因和生物体，以确定这些因素相对于废水排放口的距离的分散和命运。与距离衰减分析相结合的鸟枪法宏基因组学表明，在离排放口较近的沉积物中，与 WWTP 废水基因相同的基因的丰度高于离排放口较远的沉积物，这表明它们可能来自 WWTP。我们还发现了归因于生物体的基因，例如那些属于、、、和的基因，这些基因存在于两个 WWTP 的废水中，并且随着与 WWTP 距离的增加，在湖底沉积物中的丰度降低。此外，我们的研究结果表明，WWTP 可能会影响靠近废水排放口的湖底沉积物中的 ARG 组成。这些 ARGs 中的许多都位于废水和沉积物样本中的 MGEs 上，表明水平基因转移（HGT）的相对广泛倾向。我们的方法使我们能够将基因具体链接到生物体及其遗传背景，从而深入了解 WWTP 对自然微生物群落的影响。总的来说，我们的研究结果表明，废水处理厂的废水对受纳水体沉积物中的基因含量和微生物群落结构有很大的影响。污水处理厂（WWTP）将其废水排放到水生环境中。尽管经过处理，但废水中仍保留许多可能以人们知之甚少的方式影响受纳水的基因和微生物。在这里，我们从 WWTP 到湖底沉积物追踪了遗传足迹，包括抗生素抗性和移动遗传元件及其相关生物体特有的基因。我们的工作是新颖的，因为我们使用宏基因组数据集全面评估了受 WWTP 输入影响的环境样本中的总基因含量以及特定基因的遗传和分类学背景。基于具有不同处理工艺的两个不同 WWTP，我们的研究结果表明 WWTP 对这些因素在环境中的存在、丰度和组成有影响。
