Persistence of Bacteroides ovatus under simulated sunlight irradiation

Handle URI:
http://hdl.handle.net/10754/334605
Title:
Persistence of Bacteroides ovatus under simulated sunlight irradiation
Authors:
Dong, Shengkun; Hong, Pei-Ying ( 0000-0002-4474-6600 ) ; Nguyen, Thanh H
Abstract:
Background: Bacteroides ovatus, a member of the genus Bacteroides, is considered for use in molecular-based methods as a general fecal indicator. However, knowledge on its fate and persistence after a fecal contamination event remains limited. In this study, the persistence of B. ovatus was evaluated under simulated sunlight exposure and in conditions similar to freshwater and seawater. By combining propidium monoazide (PMA) treatment and quantitative polymerase chain reaction (qPCR) detection, the decay rates of B. ovatus were determined in the presence and absence of exogenous photosensitizers and in salinity up to 39.5 parts per thousand at 27°C. Results: UVB was found to be important for B. ovatus decay, averaging a 4 log10 of decay over 6 h of exposure without the presence of extracellular photosensitizers. The addition of NaNO2, an exogenous sensitizer producing hydroxyl radicals, did not significantly change the decay rate of B. ovatus in both low and high salinity water, while the exogenous sensitizer algae organic matter (AOM) slowed down the decay of B. ovatus in low salinity water. At seawater salinity, the decay rate of B. ovatus was slower than that in low salinity water, except when both NaNO2 and AOM were present. Conclusion: The results of laboratory experiments suggest that if B. ovatus is released into either freshwater or seawater environment in the evening, 50% of it may be intact by the next morning; if it is released at noon, only 50% may be intact after a mere 5 min of full spectrum irradiation on a clear day. This study provides a mechanistic understanding to some of the important environmental relevant factors that influenced the inactivation kinetics of B. ovatus in the presence of sunlight irradiation, and would facilitate the use of B. ovatus to indicate the occurrence of fecal contamination.
KAUST Department:
Environmental Science and Engineering Program; Water Desalination and Reuse Research Center (WDRC)
Citation:
Dong S, Hong P-Y, Nguyen TH (2014) Persistence of Bacteroides ovatus under simulated sunlight irradiation. BMC Microbiology 14: 178. doi:10.1186/1471-2180-14-178.
Publisher:
Springer Nature
Journal:
BMC Microbiology
Issue Date:
4-Jul-2014
DOI:
10.1186/1471-2180-14-178
PubMed ID:
24993443
PubMed Central ID:
PMC4099502
Type:
Article
ISSN:
1471-2180
Appears in Collections:
Articles; Environmental Science and Engineering Program; Water Desalination and Reuse Research Center (WDRC)

Full metadata record

DC FieldValue Language
dc.contributor.authorDong, Shengkunen
dc.contributor.authorHong, Pei-Yingen
dc.contributor.authorNguyen, Thanh Hen
dc.date.accessioned2014-11-11T14:31:43Z-
dc.date.available2014-11-11T14:31:43Z-
dc.date.issued2014-07-04en
dc.identifier.citationDong S, Hong P-Y, Nguyen TH (2014) Persistence of Bacteroides ovatus under simulated sunlight irradiation. BMC Microbiology 14: 178. doi:10.1186/1471-2180-14-178.en
dc.identifier.issn1471-2180en
dc.identifier.pmid24993443en
dc.identifier.doi10.1186/1471-2180-14-178en
dc.identifier.urihttp://hdl.handle.net/10754/334605en
dc.description.abstractBackground: Bacteroides ovatus, a member of the genus Bacteroides, is considered for use in molecular-based methods as a general fecal indicator. However, knowledge on its fate and persistence after a fecal contamination event remains limited. In this study, the persistence of B. ovatus was evaluated under simulated sunlight exposure and in conditions similar to freshwater and seawater. By combining propidium monoazide (PMA) treatment and quantitative polymerase chain reaction (qPCR) detection, the decay rates of B. ovatus were determined in the presence and absence of exogenous photosensitizers and in salinity up to 39.5 parts per thousand at 27°C. Results: UVB was found to be important for B. ovatus decay, averaging a 4 log10 of decay over 6 h of exposure without the presence of extracellular photosensitizers. The addition of NaNO2, an exogenous sensitizer producing hydroxyl radicals, did not significantly change the decay rate of B. ovatus in both low and high salinity water, while the exogenous sensitizer algae organic matter (AOM) slowed down the decay of B. ovatus in low salinity water. At seawater salinity, the decay rate of B. ovatus was slower than that in low salinity water, except when both NaNO2 and AOM were present. Conclusion: The results of laboratory experiments suggest that if B. ovatus is released into either freshwater or seawater environment in the evening, 50% of it may be intact by the next morning; if it is released at noon, only 50% may be intact after a mere 5 min of full spectrum irradiation on a clear day. This study provides a mechanistic understanding to some of the important environmental relevant factors that influenced the inactivation kinetics of B. ovatus in the presence of sunlight irradiation, and would facilitate the use of B. ovatus to indicate the occurrence of fecal contamination.en
dc.language.isoenen
dc.publisherSpringer Natureen
dc.rights.urihttp://creativecommons.org/licenses/by/2.0/en
dc.titlePersistence of Bacteroides ovatus under simulated sunlight irradiationen
dc.typeArticleen
dc.contributor.departmentEnvironmental Science and Engineering Programen
dc.contributor.departmentWater Desalination and Reuse Research Center (WDRC)en
dc.identifier.journalBMC Microbiologyen
dc.identifier.pmcidPMC4099502en
dc.eprint.versionPublisher's Version/PDFen
dc.contributor.institutionDepartment of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, 205 N. Mathews, 3230 Newmark Lab, Urbana, IL 61801, USAen
dc.contributor.affiliationKing Abdullah University of Science and Technology (KAUST)en
kaust.authorHong, Pei-Yingen
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