Monday, November 13, 2006 - 10:15 AM
88-3

Wastes and Water: Tracking Septage and Manure in Agricultural Watersheds by Antibiotic Resistance Patterns.

Mark Coyne, Univ of Kentucky,Dept. of Plant & Soil, N122 AG Science North, Lexington, KY 40546-0091 and Sloane Ritchey, Univ of Kentucky, Dept of Plant and Soil Sciences, 4140 Berryman Ct, Lexington, KY 40514-5900.

Nonpoint sources of fecal bacteria continuously impair water quality.  Microbial source tracking (MST) is a management tool promoting efficient resource use and timely remediation of substandard water quality due to fecal contamination.  The antibiotic resistance analysis (ARA) technique has been proposed as a useful tool for MST, but more information is needed about ARA temporal and geographic variability.  These studies evaluated ARA: (1) to distinguish human, poultry, and ‘pristine’ sites; (2) to detect temporal variability in fecal bacteria isolates; (3) to distinguish among multi-animal and human isolates; (4) to determine host origin on a watershed scale.  Correct classification rates ≥ 60% as determined by discriminant analysis are considered useful by resource managers and was the threshold level used to determine success of the MST technique.  The ARA method adequately distinguished between poultry, human, and pristine sites.  The database average rate of correct classification (ARCC) was 61%.  Temporal changes of E. coli antibiotic resistance patterns from poultry indicated a significant profile shift approximately two weeks after application.  These patterns returned to initial profiles about three to four weeks after application.  The ARA method adequately distinguished human sources from other multiple animal sources; however, sensitivity to adequately distinguish between specific animal sources declined.  Based on completed research, the use of ARA and rep-PCR methodologies for microbial source tracking is promising.  Availability of such MST tools will assist in resource management.  In this way, water quality improvement will become a less daunting task and a realizable goal.