Department Chair

Daniel L. Potts, Ph.D., Chair and Associate Professor of Biology

Date of Award


Access Control

Open Access

Degree Name

Biology, M.A.


Biology Department


Gary W. Pettibone, PhD., Professor of Biology

Department Home page

First Reader

Gary W. Pettibone, PhD., Professor of Biology and Thesis Advisor

Second Reader

Amy M. McMillan, PhD., Professor of Biology

Third Reader

Gregory J. Wadsworth, PhD., Associate Professor of Biology


Every year, thousands of people utilize beaches for recreation, but most are unaware of Escherichia coli (E. coli) contamination and the possibility of acquiring an infection. In this study, 173 strains of E. coli were isolated from sand and adjacent waters from a public beach in Erie County, NY and analyzed for genetic relatedness based on sequence differences in the variable regions of the 16S rRNA gene. Some of the variable regions (V1 and V6) proved useful in constructing phylogenetic trees but the discriminatory power of these regions was inadequate to resolve intraspecies differences. Therefore, whether extant populations of E. coli differ between water and sand environments could not be determined. All environmental isolates also were analyzed for the presence of the toxin genes: papC, sfa/foc, stx1 and stx2. None of the isolates harbored the stx1 or stx2 genes, which code for a potentially lethal Shiga toxin. However, the papC gene and the sfa/foc gene were present in 5.2% (n=9) and 7.5% (n=13) of the isolates, respectively. These genes are known to be associated with the ability of E. coli to cause urinary tract infections, and their presence in beach sand and recreational water represents a health risk to user populations.