Identification of E. coli Sources in Conesus Lake Sub-watersheds Using BOX A1R- Derived Genetic Fingerprints

Abstract

In the Conesus Lake watershed , best management practices (BMP's) were implemented on farms in the upper watershed and the resultant change in bacterial water quality was assessed using both quantification techniques and Rep-PCR molecular tools during events and non-events. Genetic fingerprints of Escherichia coli isolates from a library of known source isolates (n=123) were compared to E. coli of unknown origin obtained from stream water samples. The genetic library consisted of E. coli sources from cattle, humans, geese and deer. Fecal samples were collected aseptically and E. coli was isolated from each of these sources. Genetic fingerprints were obtained from each of the known sources using Rep-PCR. Fingerprints from unknown sources were compared with those in the library using computer based image analysis. These techniques were used to identify sources of E. coli in the watershed and accurately demonstrate the effectiveness of the best management practices in the watershed. Results found E. coli levels that were significantly higher than that established by EPA for recreational waters (200CFU/1OOml) on several occasions throughout the year, especially during event periods. In addition, the sources of E. coli in the watershed were identified.