Date of Award


Degree Type


Degree Name

Master of Science




Biology (MS)

First Advisor/Chairperson

Dr. Josh Sharp


Staphylococcus aureus is the most common cause of human bacterial infections; however, humans can also be asymptomatically colonized with S. aureus. Asymptomatic carriers can potentially spread S. aureus infection to others. These infections can range from mild to severe. The pathology of a S. aureus infection is often dependent on which toxins are expressed and the virulence factors with which they are associated. One goal of this study was to isolate S. aureus from healthy, consenting adult volunteers who submitted nasal swabs for culture and qRT-PCR analysis to determine which strains are present in the community. This knowledge could potentially lead to more informed treatment options when S. aureus infection is suspected. PCR-based subtyping was utilized to test for the presence of fifteen toxin genes: lukAB, lukED, pvl, hlgA, hlgC, tst, eta, hla, hlb, hld, sea, seb, sec, sed, and see. Isolates were also tested for the presence of the mecA gene, which encodes for methicillin-resistant strains of S. aureus.

This study was the first to attempt to identify which genes were present across all six classes of Staphylococcal toxins in community-colonized strains of S. aureus. We have laid the path toward identifying what kind of S. aureus isolates are present in our community. Further analysis using next-generation genome sequencing and spa typing will need to be utilized to compare the community strains of S. aureus isolated in this study to known disease-causing isolates from the hospital to discern if there is a correlation between the two.

Access Type

Open Access