School of Energy, Environmental, Biological & Medical Engineering, University of Cincinnati , Cincinnati, Ohio 45221, United States.
Environ Sci Technol. 2013 Sep 17;47(18):10485-93. doi: 10.1021/es4020458. Epub 2013 Aug 26.
Identifying the source of surface water fecal contamination is paramount to mitigating pollution and risk to human health. Fecal bacteria such as E. coli have been staple indicator organisms for over a century, however there remains uncertainty with E. coli-based metrics since these bacteria are abundant in the environment. The relationships between the presence of direct indicator of human waste (human mitochondrial DNA), human-specific Bacteroidales, and E. coli were studied for water samples taken from an urban creek system (Duck Creek Watershed, Cincinnati, OH) impacted by combined sewer overflows. Logistic regression analysis shows that human-specific Bacteroidales correlates much more closely to human mitochondrial DNA (R = 0.62) relative to E. coli (R = 0.33). We also examine the speciation of Bacteroidales within the Duck Creek Watershed using next-generation sequencing technology (Ion Torrent) and show the most numerous populations to be associated with sewage. Here we demonstrate that human-specific Bacteroidales closely follow the dynamics of human mitochondrial DNA concentration changes, indicating that these obligate anaerobes are more accurate than E. coli for fecal source tracking, lending further support to risk overestimation using coliforms, especially fecal coliforms and E. coli.
确定地表水粪便污染的来源对于减轻污染和人类健康风险至关重要。一百多年来，大肠杆菌等粪便细菌一直是主要的指示生物，但由于这些细菌在环境中大量存在，基于大肠杆菌的指标仍存在不确定性。本研究对来自受合流污水溢流影响的城市小溪系统（俄亥俄州辛辛那提市 Duck Creek 流域）的水样中直接人类粪便指示物（人线粒体 DNA）、人类特异性拟杆菌和大肠杆菌的存在关系进行了研究。逻辑回归分析表明，与大肠杆菌（R = 0.33）相比，人类特异性拟杆菌与人线粒体 DNA 的相关性更为密切（R = 0.62）。我们还使用下一代测序技术（Ion Torrent）检查了 Duck Creek 流域内拟杆菌的分类，结果表明，数量最多的种群与污水有关。在这里，我们证明了人类特异性拟杆菌与人线粒体 DNA 浓度变化的动态密切相关，这表明这些专性厌氧菌比大肠杆菌更适合用于粪便源追踪，这进一步支持了使用大肠菌群，特别是粪大肠菌群和大肠杆菌来高估风险的说法。
