摘要

       污水处理厂（WWTPs）将含有可移动遗传元素（MGE）、抗生素抗性基因（ARG）和微生物的处理后废水排放到环境中，但对其对附近微生物群落的影响以及这些因素在受纳水体中的滞留情况知之甚少。我们的研究旨在确定排放到密歇根湖的两个不同污水处理厂以及周围湖泊沉积物中的基因和生物特征，以确定这些因素与排放口之间距离的分散和归宿。鸟枪元基因组学结合距离衰减分析显示，与污水处理厂废水基因相同的基因在距离排污口较近的沉积物中的丰度高于在较远的沉积物中的丰度，表明它们可能是污水处理厂的起源。我们还发现，在两个污水处理厂的污水中都发现了与生物有关的基因，如螺杆菌科、军团菌科、冰碛科和奈瑟科的基因，随着与污水处理厂距离的增加，湖泊沉积物中的丰度降低。此外，我们的研究结果显示，污水处理厂可能会影响接近污水排放的湖泊沉积物中的精氨酸组成。这些arg中的许多位于废水和沉积物样品中的mge上，表明水平基因转移（HGT）具有相对广泛的倾向。我们的方法使我们能够特别地将基因与生物体及其遗传背景联系起来，从而深入了解污水处理厂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排放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。重要的废水处理厂（WWTPs）将其排放到水环境中。尽管经过处理，废水中仍保留着许多基因和微生物，这些基因和微生物有可能以鲜为人知的方式影响受纳水体。在这里，我们跟踪了从污水处理厂到湖泊沉积物的遗传足迹，包括抗生素抗性和可移动遗传元素及其相关生物的特定基因。我们的工作是新颖的，我们使用亚基因组数据集来综合评估污水处理厂输入可能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背景。基于两个不同处理工艺的污水处理厂，我们的发现指出了污水处理厂对环境中这些因素的存在、丰度和组成的影响。

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 Helicobacteraceae, Legionellaceae, Moraxellaceae, and Neisseriaceae, 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.IMPORTANCE 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.

       https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5812944/