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Paper Type

Master's Thesis


College of Arts and Sciences

Degree Name

Master of Science in Biology (MS)



NACO controlled Corporate Body

University of North Florida. Department of Biology

First Advisor

Dr. Terri Ellis

Second Advisor

Dr. Judith Ochrietor

Third Advisor

Dr. Candice Tahimic

Department Chair

Dr. Cliff Ross

College Dean

Dr. Kaveri Subrahmanyam


Klebsiella pneumoniae is a Gram-negative, non-motile bacterium belonging to the Enterobacteriaceae family. K. pneumoniae is a rising threat in the clinical setting, as there has been a large increase in the presence of antibiotic resistant isolates. While much research is conducted on laboratory and clinical strains of bacteria, not much is known regarding the impact that human physiology can have on bacterial gene expression, and in response, to antibiotic susceptibility. The goal of this study is to determine if physiologically relevant cholesterol levels and media types impact porin gene expression and antibiotic resistance in K. pneumoniae. To accomplish this, quantitative-PCR and minimum inhibitory concentration assays were utilized. The results of this study indicate that physiologically relevant levels of cholesterol and media types can have several significant effects on porin gene expression and on antibiotic resistance. Firstly, laboratory strain K. pneumoniae was more impacted by changes in cholesterol than clinical strain K. pneumoniae regarding changes to antibiotic susceptibility; however, expression varied largely across all cholesterol concentrations and genes. Secondly, gene expression was downregulated for all six tested genes in the physiologic media compared to the laboratory media; also, the physiologic media often had significantly lower antibiotic susceptibility than the laboratory media. Lastly, it was found that surfactant can have significant effects on both gene expression and antibiotic susceptibility analyses. The results indicate that physiological conditions can impact gene expression and antibiotic susceptibility. Hence, careful consideration should be given to experiments designed to mimic physiological conditions.