CSIRO Land and Water, Ecosciences Precinct, 41 Boggo Road, Qld, 4102, Australia.
BioTechnology Institute, Departments of Soil, Water & Climate, and Plant & Microbial Biology, University of Minnesota, St. Paul, MN, 55108, USA.
Water Res. 2019 Feb 1;149:511-521. doi: 10.1016/j.watres.2018.10.088. Epub 2018 Nov 2.
There is a growing move towards using the quantitative polymerase chain (qPCR)-based sewage-associated marker genes to assess surface water quality. However, a lack of understanding about the persistence of many sewage-associated markers creates uncertainty for those tasked with investigating microbial water quality. In this study, we investigated the decay of two qPCR FIB [E. coli (EC), and Enterococcus spp. (ENT) 23S rRNA genes] and four sewage-associated microbial source tracking (MST) marker genes [human Bacteroides HF183 16S rRNA, adenovirus (HAdV), and polyomavirus (HPyV), and crAssphage, a recently described bacteriophage in feces], in outdoor mesocosms containing fresh and marine waters and their corresponding sediments. Decay rates of EC 23S rRNA, ENT 23S rRNA, and HF183 16S rRNA were significantly (p < 0.05) faster than the HAdV, HPyV and crAssphage markers in water samples from all mesocosms. In general, decay rates of bacterial targets were similar in the water columns of the studied mesocosms. Similarly, decay rates of viral targets were also alike in mesocosm water columns in relation to each other. The decay rates of FIB and sewage-associated markers were significantly faster in water samples compared to sediments in all three mesocosms. In the event of resuspension, FIB and marker genes from sediments can potentially recontaminate overlying waters. Thus, care should be taken when interpreting the occurrence of FIB and sewage-associated MST markers in water, which may have originated from sediments. The differential decay of these targets may also influence health outcomes and need to be considered in risk assessment models.
人们越来越倾向于使用基于定量聚合酶链（qPCR）的污水相关标记基因来评估地表水水质。然而，由于对许多污水相关标记物的持久性缺乏了解，这给那些负责调查微生物水质的人带来了不确定性。在这项研究中，我们研究了两种 qPCR 纤维（E. coli [EC] 和肠球菌属 spp. [ENT] 23S rRNA 基因）和四种污水相关微生物源追踪（MST）标记基因[人类双歧杆菌 HF183 16S rRNA、腺病毒（HAdV）和多瘤病毒（HPyV）以及最近在粪便中描述的 crAssphage]在含有淡水和海水及其相应沉积物的户外中观模型中的衰减情况。在所有中观模型的水样中，EC 23S rRNA、ENT 23S rRNA 和 HF183 16S rRNA 的衰减率明显（p < 0.05）快于 HAdV、HPyV 和 crAssphage 标记物。一般来说，研究中观模型水柱中细菌靶标的衰减率相似。同样，在中观模型水柱中，病毒靶标的衰减率彼此之间也相似。在所有三个中观模型中，与沉积物相比，水样中 FIB 和污水相关标记物的衰减率明显更快。如果发生再悬浮，沉积物中的 FIB 和标记基因可能会重新污染上覆水。因此，在解释水中 FIB 和污水相关 MST 标记物的出现时应谨慎，这些标记物可能源自沉积物。这些目标的差异衰减也可能影响健康结果，需要在风险评估模型中加以考虑。
