Theses and Dissertations

Date of Award


Document Type


Degree Name



Basic Medical Sciences

Committee Chair

Kevin R. Macaluso, Ph.D


The genus Rickettsia is comprised of Gram-negative, obligate intracellular bacteria that are spread by hematophagous arthropods. Elucidating the factors conferring rickettsial virulence has perplexed investigators for decades, complicated by the lack of efficient genetic tools necessary to uncover rickettsial- and vector-specific factors contributing to persistence. The advent of transposon mutagenesis has enabled the field to make vast developments in uncovering novel rickettsial mechanisms utilized in various host backgrounds. Thus, the aim of this study was to generate Rickettsia felis transposon mutants and characterize novel phenotypes associated with genetic disruption in an arthropod background. Distribution of rickettsiae is reliant on the geographic range of their transmitting vector, which is ultimately influenced by a vast array of intrinsic and extrinsic factors, such as microbial coinfections. Thus, the sympatric distribution of flea-borne rickettsiae in endemic areas in the U.S. provides an opportunity to examine the effects of Rickettsia- Rickettsia interactions. Herein, the ability of naïve fleas to acquire R. felis and Rickettsia typhi and sustain coinfection was examined.