University of South Florida, College of Marine Science, 140 7th Avenue South, St. Petersburg, Florida, USA.
University of South Florida, Department of Integrative Biology, 4202 E. Fowler Avenue, Tampa, FL, USA.
Water Res. 2017 Mar 15;111:177-184. doi: 10.1016/j.watres.2017.01.004. Epub 2017 Jan 3.
Current microbial water quality monitoring is generally limited to culture-based measurements of fecal indicator bacteria (FIB). Given the many possible sources of fecal pollution within a watershed and extra-intestinal FIB reservoirs, it is important to determine source(s) of fecal pollution as a means to improve water quality and protect public health. The principal objective of this investigation was to characterize the microbial water quality of shellfish harvesting areas in the Gulf of Nicoya, Costa Rica during 2015. In order to achieve this objective, the specificity and sensitivity of 11 existing microbial source tracking (MST) PCR assays, associated with cows (BacCow), dogs (BacCan, DogBac), domestic wastewater (PMMoV), general avian (GFD), gulls (Gull2), horses (HorseBac, HoF), humans (HF183, HPyV), and pigs (PF), were evaluated using domestic wastewater and animal fecal samples collected from the region. The sensitivity of animal-associated assays ranged from 13 to 100%, while assay specificity ranged from 38 to 100%. The specificity of pepper mild mottle virus (PMMoV) and human polyomavirus (HPyV) was 100% for domestic wastewater, as compared to 94% specificity of the HF183 Bacteroidales marker. PMMoV was identified as a useful domestic wastewater-associated marker, with concentrations as high as 1.1 × 10 copies/ml and 100% sensitivity and specificity. Monthly surface water samples collected from four shellfish harvesting areas were analyzed using culture-based methods for Escherichia coli as well as molecular methods for FIB and a suite of MST markers, which were selected for their specificity in the region. While culturable E. coli results suggested possible fecal pollution during the monitoring period, the absence of human/domestic wastewater-associated markers and low FIB concentrations determined using molecular methods indicated sufficient microbial water quality for shellfish harvesting. This is the first study to our knowledge to test the performance of MST markers in Costa Rica as well as in Central America. Given the lack of wastewater treatment and the presence of secondary sources of FIB, this study highlights the importance of an MST toolbox approach to characterize water quality in tropical regions. Furthermore, it confirms and extends the geographic range of PMMoV as an effective tool for monitoring domestic wastewater pollution.
目前的微生物水质监测通常仅限于对粪便指示细菌 (FIB) 的基于培养的测量。鉴于流域内可能存在许多粪便污染源和肠道外 FIB 储库，确定粪便污染源的来源对于改善水质和保护公众健康非常重要。本研究的主要目的是在 2015 年 characterizing 哥斯达黎加尼科亚湾贝类捕捞区的微生物水质。为了实现这一目标，评估了 11 种现有的微生物源追踪 (MST) PCR 检测方法的特异性和敏感性，这些方法与牛 (BacCow)、狗 (BacCan、DogBac)、生活污水 (PMMoV)、普通禽 (GFD)、海鸥 (Gull2)、马 (HorseBac、HoF)、人类 (HF183、HPyV) 和猪 (PF) 相关。使用从该地区收集的生活污水和动物粪便样本评估了这些方法的特异性和敏感性。动物相关检测方法的敏感性范围为 13% 至 100%，而检测方法的特异性范围为 38% 至 100%。与 94%特异性的 HF183 拟杆菌属标记物相比，辣椒温和斑点病毒 (PMMoV) 和人多瘤病毒 (HPyV) 对生活污水的特异性为 100%。PMMoV 被确定为一种有用的生活污水相关标记物，其浓度高达 1.1×10 拷贝/ml，具有 100%的敏感性和特异性。使用基于培养的方法对来自四个贝类捕捞区的每月地表水样本进行了分析，以检测大肠杆菌，以及使用分子方法检测 FIB 和一系列 MST 标记物，这些标记物因其在该地区的特异性而被选中。虽然可培养的大肠杆菌结果表明在监测期间可能存在粪便污染，但分子方法确定的人类/生活污水相关标记物的缺失和低 FIB 浓度表明贝类捕捞的微生物水质充足。这是我们所知的首次在哥斯达黎加以及中美洲测试 MST 标记物性能的研究。鉴于缺乏污水处理和 FIB 的二次来源，本研究强调了使用 MST 工具包方法来表征热带地区水质的重要性。此外，它证实并扩展了 PMMoV 作为监测生活污水污染的有效工具的地理范围。
