PH18 Assessing Human/Environment Interactions
Exhibit Hall
8:00 AM - Thursday
(PH204) Cross-watershed assessment of a library-dependent fecal source tracking method.
Larsen, G1, Farmer, J2, Bailey, F1, 1 Middle Tennessee State University, Murfreesboro, TN, USA2 Tennessee State University, Nashville, TN, USA
ABSTRACT- Management and remediation of fecal contamination in environmental waters, which continues to pose a serious health risk in the U.S., is most effective if the sources of the contamination can be identified. Carbon utilization pattern (CUP) profiles developed using the Biolog identification system is one of many methods that can be used for bacterial source tracking. Initially, libraries containing CUP profiles of bacteria isolated from various host source fecal samples are developed. By employing discriminant analysis, these CUP profiles from known host sources can then be used to group isolates from natural waters according to host source. A common criticism of this and similar library-dependent methods is that they are subject to spatial limitations, necessitating the development of separate libraries for every watershed or region. This study was designed to test the ability of our CUP library from the Duck River watershed to identify sources of Enterococcus isolates from the Stones River watershed. Both of these watersheds are in central Tennessee and have aquatic fecal contamination from wildlife, agricultural and human sources. For purposes of this study, only Enterococcus isolates from cows, sewage and septic systems were used. 36 bacterial isolates from the genus Enterococcus were collected from bovine sources in the Stones River watershed and their CUP profiles generated. Discriminant analysis was then used to determine if the source could be correctly identified using the Duck River library. This analysis correctly identified 19% of the bovine isolates. 70% of the remaining isolates were identified as sewage and 11% as septic. While this is a somewhat limited test, it does imply that CUP profile libraries for fecal bacterial source tracking are watershed specific. It will require more testing to determine if a larger library may improve results.
Key words: carbon utilization profiles, bacterial source tracking, Enterococcus