Q-256. Microbial Source Tracking of Fecal Contamination in Southwest Missouri Streams Using Bacteroides PCR and qPCR Methodology

J. G. Steiert, N. J. Vanasch;
Missouri State Univ., Springfield, MO.

Freshwater streams in southwest Missouri are widely used for recreational purposes and attract many tourists to the area. This area of the state has seen a dramatic increase in population over last few decades with many rural areas becoming urbanized. The James River basin is a major drainage basin in southwest Missouri and many of its tributaries are used for a variety of recreational activities. Over the last several years many county health departments have posted warnings about the use of certain areas of the stream for swimming because of high Escherichia coli levels, indicating fecal pollution. Previous research by our laboratory and others, have identified various sites in the basin with consistently high levels of E. coli. In this study we used a microbial source tracking method to help identify the sources of fecal pollution. Bacteroides host-specific primers have been developed to differentiate between ruminant- and human-associated Bacteroides sp. Both an end point and a quantitative PCR assay were used in the study. Six sampling sites were selected based upon past research. Three sites on the Finley River and three sites on Wilson’s Creek were sampled three times per month during the spring, summer, and fall and twice a month during the winter. For each sampling event flow rate, water temperature, 24 hour precipitation amounts, dissolved oxygen, and E. coli levels were determined, in addition to the Bacteroides PCR assays. The results from the PCR and qPCR assays were compared to E. coli levels and the other water quality determinants. Results indicated ruminant contamination in most samples tested and human contamination in several of the samples. The qPCR assay enabled us to correlate E. coli levels with levels of fecal contamination. The qPCR assay allowed us to identify sample sites that were heavily contaminated with human feces, which may indicate a greater human health risk.