Bacteroides spp. has gained substantial interest among the suggested potential candidates for alternative faecal indicators for untreated recreational waters by the US EPA. Interest in Bacteroides as a faecal indicator is based upon the relative abundance of selected members of the Bacteroides genus in the human colon and human faeces. In this study, we developed a real-time PCR detection system based on gyrase B subunit genes (gyrB) specific to Bacteroides fragilis. The gryB-based method was compared with previously described 16S rRNA-based real-time qPCR methods and evaluated for specificity, sensitivity and robustness in detecting B. fragilis from untreated recreational water impacted by human and non-human faecal sources. The new gyrB-based system only detected B. fragilis, whereas the 16S rRNA-based methods generated cross-amplifications with other Bacteroides and Prevotella species. We used a procedure of prefiltration, filtration, sonication and DNA concentration in order to improve the DNA extraction efficiency and the sensitivity of the real-time PCR while removing interference. The amplification and sequencing of PCR products generated by the gyrB-based method confirmed that gyrB-amplified sequences only contained B. fragilis. This rapid method is useful for quantifying faecal contamination and may assist beach and watershed managers in elucidating possible contamination sources.
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Research Article|
April 25 2011
A novel genetic marker for the rapid detection of Bacteroides fragilis in recreational water as a human-specific faecal indicator
Chang Soo Lee;
1College of Public Health, Division of Environmental Health Sciences, The Ohio State University, Columbus, OH 43210, USA
E-mail: [email protected]
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Jason W. Marion;
Jason W. Marion
1College of Public Health, Division of Environmental Health Sciences, The Ohio State University, Columbus, OH 43210, USA
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Jiyoung Lee
Jiyoung Lee
2Department of Food Science & Technology, The Ohio State University, Columbus, OH 43210, USA
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J Water Health (2011) 9 (2): 253–264.
Article history
Received:
July 09 2010
Accepted:
November 25 2010
Citation
Chang Soo Lee, Jason W. Marion, Jiyoung Lee; A novel genetic marker for the rapid detection of Bacteroides fragilis in recreational water as a human-specific faecal indicator. J Water Health 1 June 2011; 9 (2): 253–264. doi: https://doi.org/10.2166/wh.2011.120
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