Host Specific Microbial Source Tracking and Quantification Using the Partial 16SrRNA Gene Sequence of Bacteroides on the Wilson's Creek Tributary in Southwest Missouri

Date of Graduation

Fall 2008


Master of Science in Biology



Committee Chair

John Steiert


Fecal contamination is a major issue that county health departments address to protect the many individuals that enjoy recreational streams. Pathogens that accompany fecal contamination can cause severe human health problems. Many different point and non-point sources of fecal contamination influence Wilson's Creek in Southwest Missouri. Use of Escherichia coli for identification of fecal contamination in fresh water streams is the commonly used method approved by the EPA, but is limited in the ability to be associated with a specific host. The purpose of this study was to look at land use around Wilson's Creek and to identify and quantify sources that interact with land to determine which source contributes the most contamination. A real-time PCR assay using Bacteroides host-associated 16SrRNA marker genes was used, along the with Colilert E. coli MPN enumeration method for this survey. There were multiple occasions at each site where the E. coli MPN exceeded the Missouri DNR recommended safety standard of 126MPN/100ml. Bovine-associated Bacteroides were detected at every site. Human-associated markers were detected less frequently, but were present on several occasions. Host-associated marker concentrations were three to four orders of magnitude less than general Bacteroides. The highest levels of bovine-associated markers were observed at the WC Bridge (site 2), which is heavily impacted by livestock. Human-associated marker levels were highest at the WC STP (site 1) which is located just downstream of the City of Springfield waste water treatment plant, and the WC Bridge


bacteroides, real-time PCR, fecal indicator, 16SrRNA marker, MPN

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© Anthony R. Saitta