Survival and persistence of host-associated Bacteroidales cells and DNA in comparison with Escherichia coli and Enterococcus in freshwater sediments as quantified by PMA-qPCR and qPCR
Decay of the fecal source identifier Bacteroidales in sediments has not been studied until now. Two types of microcosms inoculated with human, cow and dog feces were constructed to investigate the survival and persistence of host-associated Bacteroidales cells and their DNA, respectively, in freshwa...
| Main Authors: | , |
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| Format: | Journal Article |
| Language: | English |
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2015
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| Online Access: | https://hdl.handle.net/10356/80952 http://hdl.handle.net/10220/38977 |
| _version_ | 1811678759611269120 |
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| author | Kim, Minji Wuertz, Stefan |
| author2 | School of Civil and Environmental Engineering |
| author_facet | School of Civil and Environmental Engineering Kim, Minji Wuertz, Stefan |
| author_sort | Kim, Minji |
| collection | NTU |
| description | Decay of the fecal source identifier Bacteroidales in sediments has not been studied until now. Two types of microcosms inoculated with human, cow and dog feces were constructed to investigate the survival and persistence of host-associated Bacteroidales cells and their DNA, respectively, in freshwater sediments: (i) a completely anaerobic microcosm where feces were entirely mixed with sediments for estimating decay of Bacteroidales in oxygen-free sediments at two temperatures (6 °C and 20 °C) and (ii) a core microcosm where feces in the overlying water column settled on top of undisturbed core sediments. Quantitative PCR (qPCR) along with propidium monoazide (PMA) was used to differentiate between genetic markers present in intact cells and total intracellular as well as extracellular marker DNA. Regulated fecal indicator bacteria were measured by cultivation (Escherichia coli and Enterococcus) and qPCR (Enterococcus) in relation to Bacteroidales-associated host markers. In anaerobic microcosms, the survival and persistence of Bacteroidales cells and DNA in sediments were considerably extended, especially at the lower temperature of 6 °C, with two-log reduction times (T99) >56 d (cells) and >169 d (DNA). Bacteroidales DNA persisted up to five times longer than cells in anaerobic microcosms at 6 °C, whereas decay rates of cells and DNA were not significantly different at 20 °C in anaerobic microcosms. In core microcosms, the levels of Bacteroidales cells and DNA decreased approximately six times more slowly in sediments than in overlying water; T99 values of Bacteroidales cells and DNA were 6–9 d (water) and 29–82 d (sediment). The survival of universal, human-, ruminant- and dog-associated Bacteroidales cells in sediments was similar in both microcosms under each given condition, as was the persistence of DNA. Decay rate constants of Bacteroidales cells and DNA were comparable with those of cultivable Enterococcus and E. coli cells in core sediments while Enterococcus DNA levels fluctuated without noticeable decay. The prolonged persistence of host-associated Bacteroidales suggests that sediments should be considered in practical applications of microbial source tracking, because they can act as non-point sources of fecal markers. |
| first_indexed | 2024-10-01T02:58:22Z |
| format | Journal Article |
| id | ntu-10356/80952 |
| institution | Nanyang Technological University |
| language | English |
| last_indexed | 2024-10-01T02:58:22Z |
| publishDate | 2015 |
| record_format | dspace |
| spelling | ntu-10356/809522020-09-21T11:32:09Z Survival and persistence of host-associated Bacteroidales cells and DNA in comparison with Escherichia coli and Enterococcus in freshwater sediments as quantified by PMA-qPCR and qPCR Kim, Minji Wuertz, Stefan School of Civil and Environmental Engineering Singapore Centre for Environmental Life Sciences Engineering Bacteroidales Fecal indicator bacteria Propidium monoazide Sediment Microbial source tracking Quantitative PCR Decay of the fecal source identifier Bacteroidales in sediments has not been studied until now. Two types of microcosms inoculated with human, cow and dog feces were constructed to investigate the survival and persistence of host-associated Bacteroidales cells and their DNA, respectively, in freshwater sediments: (i) a completely anaerobic microcosm where feces were entirely mixed with sediments for estimating decay of Bacteroidales in oxygen-free sediments at two temperatures (6 °C and 20 °C) and (ii) a core microcosm where feces in the overlying water column settled on top of undisturbed core sediments. Quantitative PCR (qPCR) along with propidium monoazide (PMA) was used to differentiate between genetic markers present in intact cells and total intracellular as well as extracellular marker DNA. Regulated fecal indicator bacteria were measured by cultivation (Escherichia coli and Enterococcus) and qPCR (Enterococcus) in relation to Bacteroidales-associated host markers. In anaerobic microcosms, the survival and persistence of Bacteroidales cells and DNA in sediments were considerably extended, especially at the lower temperature of 6 °C, with two-log reduction times (T99) >56 d (cells) and >169 d (DNA). Bacteroidales DNA persisted up to five times longer than cells in anaerobic microcosms at 6 °C, whereas decay rates of cells and DNA were not significantly different at 20 °C in anaerobic microcosms. In core microcosms, the levels of Bacteroidales cells and DNA decreased approximately six times more slowly in sediments than in overlying water; T99 values of Bacteroidales cells and DNA were 6–9 d (water) and 29–82 d (sediment). The survival of universal, human-, ruminant- and dog-associated Bacteroidales cells in sediments was similar in both microcosms under each given condition, as was the persistence of DNA. Decay rate constants of Bacteroidales cells and DNA were comparable with those of cultivable Enterococcus and E. coli cells in core sediments while Enterococcus DNA levels fluctuated without noticeable decay. The prolonged persistence of host-associated Bacteroidales suggests that sediments should be considered in practical applications of microbial source tracking, because they can act as non-point sources of fecal markers. Accepted version 2015-12-07T05:09:38Z 2019-12-06T14:18:09Z 2015-12-07T05:09:38Z 2019-12-06T14:18:09Z 2015 Journal Article Kim, M., & Wuertz, S. (2015). Survival and persistence of host-associated Bacteroidales cells and DNA in comparison with Escherichia coli and Enterococcus in freshwater sediments as quantified by PMA-qPCR and qPCR. Water Research, 87, 182-192. 0043-1354 https://hdl.handle.net/10356/80952 http://hdl.handle.net/10220/38977 10.1016/j.watres.2015.09.014 en Water Research © 2015 Elsevier Ltd. This is the author created version of a work that has been peer reviewed and accepted for publication by Water Research, Elsevier Ltd. It incorporates referee’s comments but changes resulting from the publishing process, such as copyediting, structural formatting, may not be reflected in this document. The published version is available at: [http://dx.doi.org/10.1016/j.watres.2015.09.014]. 33 p. application/pdf |
| spellingShingle | Bacteroidales Fecal indicator bacteria Propidium monoazide Sediment Microbial source tracking Quantitative PCR Kim, Minji Wuertz, Stefan Survival and persistence of host-associated Bacteroidales cells and DNA in comparison with Escherichia coli and Enterococcus in freshwater sediments as quantified by PMA-qPCR and qPCR |
| title | Survival and persistence of host-associated Bacteroidales cells and DNA in comparison with Escherichia coli and Enterococcus in freshwater sediments as quantified by PMA-qPCR and qPCR |
| title_full | Survival and persistence of host-associated Bacteroidales cells and DNA in comparison with Escherichia coli and Enterococcus in freshwater sediments as quantified by PMA-qPCR and qPCR |
| title_fullStr | Survival and persistence of host-associated Bacteroidales cells and DNA in comparison with Escherichia coli and Enterococcus in freshwater sediments as quantified by PMA-qPCR and qPCR |
| title_full_unstemmed | Survival and persistence of host-associated Bacteroidales cells and DNA in comparison with Escherichia coli and Enterococcus in freshwater sediments as quantified by PMA-qPCR and qPCR |
| title_short | Survival and persistence of host-associated Bacteroidales cells and DNA in comparison with Escherichia coli and Enterococcus in freshwater sediments as quantified by PMA-qPCR and qPCR |
| title_sort | survival and persistence of host associated bacteroidales cells and dna in comparison with escherichia coli and enterococcus in freshwater sediments as quantified by pma qpcr and qpcr |
| topic | Bacteroidales Fecal indicator bacteria Propidium monoazide Sediment Microbial source tracking Quantitative PCR |
| url | https://hdl.handle.net/10356/80952 http://hdl.handle.net/10220/38977 |
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