Development of DNA Marker Gene System to Determine Sources of Fecal E. Coli in Watersheds

Project Staff: 

Principal Investigator: Michael Sadowsky, Department of Soil, Water, and Climate, University of Minnesota


USGS-WRRI 104B/ CAIWQ Competitive Grants Program

Project Duration: 

March 2006 - February 2008


The contamination of waterways with fecal material remains a persistent threat to public health. Identification of sources of fecal contamination is a vital component for abatement strategies and in the determination of sources of total maximum daily loads. While phenotypic and genotypic techniques have been used to determine potential sources of fecal bacteria in surface waters, most methods require the construction of large source-know libraries, and often fail to adequately differentiate among environmental isolates originating from diverse animal sources. In contrast, library-dependent, gene probe methods may provide a cost-effective approach to determine sources of environmental isolates originating from different animal sources. In this proposal, we will use the suppression subtractive hybridization technique to enrich fro host-specific DNA markers for E. coli originating from cows an humans. We have previously used this approach to identify DNA markers for E. coli in Lake Superior. The second objective of the proposed research is to use the newly identified DNA markers (and the existing goose marker gene) as gene probes to determine sources of E. coli in the Minneopa Creek watershed. Analyses will be done using a recently developed high throughput, automated, macroarray screening procedure. The identified markers will provide a quantitative, cost-effective, and accurate library-independent method to determine sources of genetically diverse E. coli for use in source tracking studies.


Refereed Scientific Journal Articles

Yan, T., M. Hamilton, and M. J. Sadowsky. 2007. High throughput and quantitative procedure for determining sources of Escherichia coli in waterways using host−specific DNA marker genes. Applied and Environmental Microbiology 73:890–896.

Conference Proceedings

Sadowsky, M. J. 2006. Alternate source and sinks of Pathogens in the Environment. ASA/CSSA/SSSA Annual Meetings, Indianapolis, IN. November 12−16, 2006.

Other Presentations

Sadowsky, M.J. 2008. Microbial Source Tracking Methods: Myths and Realities. Oral Presentation. Minnesota Pollution Control Agency, St. Paul, MN.

Sadowsky, M.J. 2007. Development and Use of Marker Genes to Determine Sources and Sinks of Fecal Bacteria and Pathogens in the Environment. Oral Presentation. University of Montana Missoula, MT.

Sadowsky, M.J. 2007. Library−Dependent Genotypic Methods for MST Studies. Oral Presentation. EpiNet, Chicago, IL.

Sadowsky, M. J. 2006. Development and Use of a High−Throughput Robotic Method to Determine Sources of E. coli in the Environment, University of South Florida, Tampa, FL.

Sadowsky, M. J. 2006. Has Human Activity Outstripped the Environments Ability to Rid Itself of Fecal Bacteria? Albrecht Lecture, Earth Day, University of Missouri, Columbia, MO.