College of Public Health, Division of Environmental Health Sciences, The Ohio State University, Columbus, OH 43210, USA.
College of Public Health, Division of Environmental Health Sciences, The Ohio State University, Columbus, OH 43210, USA.
Sci Total Environ. 2020 Jun 25;723:138033. doi: 10.1016/j.scitotenv.2020.138033. Epub 2020 Mar 19.
Non-point stormwater runoff is a major contamination source of receiving waterbodies. Heightened incidence of waterborne disease outbreaks related to recreational use and source water contamination is associated with extreme rainfall events. Such extreme events are predicted to increase in some regions due to climate change. Consequently, municipal separate storm sewer systems (MS4s) conveying pathogens to receiving waters are a growing public health concern. In addition, the spread of antibiotic resistance genes (ARGs) and antibiotic resistant bacteria in various environmental matrices, including urban runoff, is an emerging threat. The resistome and microbiota profile of MS4 discharges has yet to be fully characterized. To address this knowledge gap, we first analyzed the relationship between rainfall depth and intensity and E. coli densities (fecal indicator) in stormwater from four MS4 outflows in Columbus, Ohio, USA during the spring and summer of 2017. Microbial source tracking (MST) was conducted to examine major fecal contamination sources in the study sewersheds. A subset of samples was analyzed for microbial and resistome profiles using a metagenomic approach. The results showed a significant positive relationship between outflow E. coli density and rainfall intensity. MST results indicate prevalent fecal contamination from ruminant populations in the study sites (91% positive among the samples tested). Protobacteria and Actinobacteria were two dominant bacteria at a phylum level. A diverse array of ARGs and potentially pathogenic bacteria (e.g. Salmonella enterica Typhimurium), fungi (e.g. Scedosporium apiospermum), and protists (e.g. Acanthamoeba palestinensis) were found in urban stormwater outflows that discharge into adjacent streams. The most prevalent ARGs among samples were β-lactam resistance genes and the most predominant virulence genes within bacterial community were related with Staphylococcus aureus. A comprehensive contamination profile indicates a need for sustainable strategies to manage urban stormwater runoff amid increasingly intense rainfall events to protect public and environmental health.
非点源雨水径流是受纳水体的主要污染源。与娱乐用水和水源污染有关的水传播疾病爆发的发生率增加与极端降雨事件有关。由于气候变化，预计一些地区的此类极端事件会增加。因此，输送病原体到受纳水体的市政单独雨水下水道系统 (MS4) 成为日益严重的公共卫生问题。此外，包括城市径流在内的各种环境基质中抗生素耐药基因 (ARGs) 和抗生素耐药细菌的传播是一个新出现的威胁。MS4 排放物的抗药性组和微生物组特征尚未得到充分描述。为了解决这一知识空白，我们首先分析了 2017 年春夏两季美国俄亥俄州哥伦布市四个 MS4 出口的雨水径流中降雨深度和强度与大肠杆菌密度（粪便指示物）之间的关系。进行了微生物来源追踪 (MST) 以检查研究下水道流域中的主要粪便污染来源。使用宏基因组方法对一部分样本进行了微生物和抗药性组分析。结果表明，流出物大肠杆菌密度与降雨强度之间存在显著正相关。MST 结果表明，研究地点的反刍动物种群存在普遍的粪便污染（在所测试的样本中，91%呈阳性）。原核生物和放线菌是门水平上的两种主要细菌。在排入相邻溪流的城市雨水流出物中发现了各种抗生素耐药基因和潜在的致病性细菌（例如肠炎沙门氏菌 Typhimurium）、真菌（例如棘孢木霉）和原生动物（例如巴勒斯坦棘阿米巴）。在样本中最常见的抗生素耐药基因是β-内酰胺类耐药基因，细菌群落中最主要的毒力基因与金黄色葡萄球菌有关。全面的污染概况表明，需要采取可持续的策略来管理城市雨水径流，以应对日益强烈的降雨事件，从而保护公众和环境健康。
