Midway Honors, Honors in Health Sciences: Human Health
Date of Award
Dr. Phillip R. Scheuerman
Thesis Professor Department
Dr. Kurt J. Maier
In recreational waters, pathogen pollution is a major concern for the USEPA. The USEPA is responsible for initiating the National 303(d) List of Impaired Surface Waters. Pathogen pollution from E. coli is a common reason why recreational waters are placed on the 303(d) list. E. coli O157 H:7 and other enteric pathogens can cause serious illness and even death. Sinking Creek is a part of the Watauga River watershed which runs through Carter and Washington county. Sinking Creek is currently listed on the 303(d) as impaired due to the presence of E. coli. Because of the known presence of E. coli, it is possible that other enteric pathogens may exist in the creek. The main objective of the study was to determine the presence of E. coli and Salmonella bacteria within Sinking Creek and was accomplished by using selective media to isolate the bacteria. The second goal of the study was to understand how various temperature treatments effect the growth of Salmonella and E. coli in Sinking Creek. Water samples from Sinking Creek were incubated at 4, 28, and 37°C. The third objective of the study was to determine how the survival of Salmonella and E. coli from Sinking Creek compared to samples taken from manure slurry via a meta-evaluation. It was predicted that Salmonella would not be present in water samples taken from Sinking Creek. It was further hypothesized that E. coli and any present Salmonella would have limited to no growth at 4°C and the most growth would occur at 37°C. A pilot study was conducted to determine the growth of microorganisms naturally present in Sinking Creek. The data from the pilot study was used to determine the creek’s ability to support a healthy microbiota. Samples for the main experiment were taken from September 2019 to November 2019. The main experiment found that Salmonella was present in Sinking Creek at lower amounts than E. coli. Both E. coli and Salmonella grew significantly at 4°C. On average, the least amount of growth for Salmonella and E. coli was at 37°C. Most growth on R2A peaked at 5 days of incubation. Water incubated at 37°C showed the highest growth peaks at 5 days for all three selective plates. For all three selective plates, water incubated at 4°C peaked in growth between days 5 and 7. The results of the main experiment could have been affected by factors such as contamination. Another limitation of the study was that enumeration of the colony forming units became less accurate after larger colonies had formed. Replicating the main experiment over a longer period could indicate more representative growth curves. The meta-evaluation concluded there was no difference in decay rate between samples taken from water or manure. The results of the meta-evaluation disproved the hypothesis that manure would have lower decay rates than samples taken from water. A larger sample size is recommended to yield more representative results for the meta-evolution. Further replications of the main experiment are recommended along with studies sampling the presence of Salmonella and E. coli at various distances from the below wetlands site.
East Tennessee State University
Honors Thesis - Withheld
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Liner, Miranda, "Determining How Temperature Affects the Survival of Salmonella and E. coli Species in Sinking Creek: A Meta-Evaluation" (2019). Undergraduate Honors Theses. Paper 517. https://dc.etsu.edu/honors/517
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