Department of Sanitary and Environmental Engineering, Federal University of Minas Gerais, Escola de Engenharia, 30270-901, Belo Horizonte, Brazil.
Water Sci Technol. 2010;61(3):813-9. doi: 10.2166/wst.2010.967.
Molecular techniques have been commonly used to detect and quantify pathogenic bacteria in food, clinical and environmental samples, but in wastewater treatment plants few studies have been carried out. This work applied PCR with a specific set of primers to investigate pathogenic bacteria in a wastewater plant comprised of a UASB reactor followed by polishing ponds. In addition, in-situ hybridisation technique (FISH) was used to estimate the abundance of Escherichia coli in the system. According to the PCR results it was observed that Escherichia coli and Salmonella enterica subsp. enterica were not completely removed in the system, since they were detected either in the raw sewage or UASB and pond effluents. Shigella dysenteriae and Enterococcus spp. were detected in raw sewage and UASB, but not in the pond effluent. In contrast Staphylococcus aureus and Helicobacter pylori were not detected in any samples. The quantification of E. coli using FISH revealed values in the range of 10(7) cells/100 mL for raw sewage and 10(6) cells/100 mL for pond effluent, slightly higher than values obtained by traditional techniques. Finally the results show the applicability of PCR method for monitoring pathogenic bacteria in wastewater systems; however, more samples need to be analysed in order to certify the applicability of FISH to estimate pathogenic bacteria in WWT effluents.
分子技术常用于检测和定量食品、临床和环境样本中的致病菌，但在废水处理厂中，此类研究很少。本工作采用特定的引物聚合酶链反应（PCR），调查了由上流式厌氧污泥床（UASB）反应器和抛光塘组成的废水处理厂中的致病菌。此外，还采用原位杂交技术（FISH）来估计系统中大肠杆菌的丰度。根据 PCR 结果，观察到大肠杆菌和肠炎沙门氏菌亚种在系统中并未被完全去除，因为它们在原污水或 UASB 和池塘废水中均有检出。志贺氏菌和肠球菌属在原污水和 UASB 中被检出，但在池塘废水中未检出。相比之下，金黄色葡萄球菌和幽门螺杆菌在任何样本中均未检出。使用 FISH 对大肠杆菌进行定量，结果显示原污水中的值在 10(7)个细胞/100 毫升范围内，池塘废水中的值在 10(6)个细胞/100 毫升范围内，略高于传统技术的检测值。最后，结果表明 PCR 方法适用于监测废水处理系统中的致病菌，但需要进一步分析更多的样本，以确定 FISH 适用于估计 WWT 废水中的致病菌。
