Browsing by Author "Stettner, Sean"

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Detection and source tracking of Escherichia coli, harboring intimin and Shiga toxin genes, isolated from the Little Bighorn River, Montana
(2014-09) Hamner, Steve; Broadaway, Susan C.; Berg, Ethan; Stettner, Sean; Pyle, Barry H.; Big Man, N.; Old Elk, J.; Eggers, Margaret J.; Doyle, John T.; Kindness, L.; Good Luck, B.; Ford, Tim E.; Camper, Anne K.
The Little Bighorn River flows through the Crow Indian Reservation in Montana. In 2008, Escherichia coli concentrations as high as 7,179 MPN/100 ml were detected in the river at the Crow Agency Water Treatment Plant intake site. During 2008, 2009, and 2012, 10 different serotypes of E. coli, including O157:H7, harboring both intimin and Shiga toxin genes were isolated from a popular swim site of the Little Bighorn River in Crow Agency. As part of a microbial source tracking study, E. coli strains were isolated from river samples as well as from manure collected from a large cattle feeding operation in the upper Little Bighorn River watershed; 23% of 167 isolates of E. coli obtained from the manure tested positive for the intimin gene. Among these manure isolates, 19 were identified as O156:H8, matching the serotype of an isolate collected from a river sampling site close to the cattle feeding area.
Microbial Source Tracking of Escherichia coli in the Little Big Horn River, Montana
(2013-03) Berg, Ethan; Stettner, Sean; Hamner, Steve
The method of microbial source tracking was used to determine the source of the gram-negative bacterium Escherichia coli. When E. coli is isolated from a water source, it indicates a possible public health risk due to fecal contamination of the water. Knowing the source of the E. coli can aid in elimination of the contamination. This project was a continuation of an ongoing project that examined E. coli isolates from various cattle ranches at various points along the Little Big Horn River and its tributaries in southeast Montana. This experiment used polymerase chain reaction (PCR) coupled with gel electrophoresis to create a database of DNA fingerprints. Multiple primers were to be used originally, however the BOXA1R and (GTG)5 primers displayed far too complex fingerprints for accurate analysis, therefore the ERIC primer set was used as a basis for creating the fingerprint database. That database was created using the GelCompar II software by Applied Maths. Using this software, all fingerprints were compared using a similarity matrix to create a list of possible matches of E. coli obtained from the various ranches, the river, and its tributaries. Preliminary results suggest possible matches between some of the manure lots on the largest ranch and various drainage sites into the river. Current work is being done using the BOXA1R and (GTG)5 primers to confirm validity of the matches found by the ERIC primer set.