Principal Investigator: Michael Sadowsky
Organization(s): University of Minnesota, Department of Soil, Water, and Climate
Sponsor: Clean Water Legacy Act
Award Amount: $240,000
Start Date: 3/1/2007 | End Date: 6/30/2009
Project Manager(s): Adam Birr
Development of DNA Marker Gene Systems for E.coli from Cows, Pigs, and Turkeys: Part 1 (PDF: 129 KB/ 6 pages)
Development of DNA Marker Gene Systems for E.coli from Cows, Pigs, and Turkeys: Part 2 (PDF: 466 KB / 51 pages)
Fecal loading of aquatic environments by animals is of concern for public and environmental health. The deposition of fecal bacteria into waterways is thought to be one of the main routes by which humans are exposed to pathogens. The microbiological contamination of waterways is amongst the most commonly listed water quality impairment in the U.S. (USEPA, 2005).
When any impairment occurs, states must conduct a Total Maximum Daily Load (TMDL) assessment in order to mitigate the impairment and restore the water body to acceptable quality. A critical step in this process is to identify the source(s) of bacteria and implement management practices that reduce pollutant loading.
In the first part of the study, researchers utilized subtraction suppressive hybridization (SSH) to identify DNAs that are specific for Escherichia coli (E. coli) originating from cows, pigs, and turkeys. Also, they were evaluating and using DNA PCR primers that are specific for fecal bacteria (members of the order Bacteroidales) originating from humans and cows. These host specific markers were used in the second part of the study to determine the source of fecal contamination on a watershed scale.
Figure 1. Multiples polymerase chain reaction done to determine the presence of
total Bacteroides (lower band) and human specific Bacteroides (upper band) in water
samples using specific DNA probes.
In part two of this study, researchers assessed the spatial and temporal dynamics of bovine fecal loading to a small creek system in southeastern Minnesota, the Little Jordan Creek.
The purpose of the second part of this study was to:
Field investigations were performed on the Little Jordan Creek, near Chatfield, Minnesota. Five sites were sampled in 2008 and 2009. These sites included areas of the creek that were thought to be significantly impacted by grazing practices, and areas thought to have less cattle impact.
Two different molecular techniques were used to determine the presence and concentration of E.coli and fecal coliform within a specific watershed. For a more detailed discussion of the quantitative PCR protocol and plate count analysis refer to part two of the research report (PDF: 412 KB / 51 pages).
Supervisor, Clean Water Technical Unit