Defense Date


Document Type


Degree Name

Master of Science


Microbiology & Immunology

First Advisor

Dr. Richard Marconi (PhD)

Second Advisor

Dr. Todd Kitten (PhD)

Third Advisor

Dr. Ping Xu (PhD)


Periodontal disease (PD) is a polymicrobial infection characterized by inflammation of the gingiva, alveolar bone resorption, and tooth loss (edentulism). Treponema denticola along with Porphyromonas gingivalis and Tannerella forsythia are among the “Red Complex” and are main etiological agents in PD. Treponemes are a member of the Spirochaeta phylum and are obligate anaerobes, that express pyruvate ferredoxin oxidoreductase (PFOR). The enzyme catalyzes the oxidation of pyruvate to acetyl-CoA and reduced ferredoxin. Amixicile is a novel bacteriostatic derivative of nitazoxanide and an inhibitor of PFOR. In light of the fact that Treponemes express PFOR, this study was conducted to investigate the susceptibility of oral Treponemes to AMX. All oral Treponemes tested were susceptible to AMX and the MIC values were determined ranging of 1.5-4.5 μg mL-1 for an initial starting cell concentration of 1.9x106 cells mL-1. Other potentially therapeutic effects for AMX for T. denticola were investigated: motility, hydrogen sulfide production, and serum sensitivity. AMX reduced overall spirochete motility by 50% at sub-MIC concentrations. There was a dose dependent decrease in H2S production in T. denticola at sub-MIC and MIC values. Furthermore, prior exposure of AMX led to increases in serum sensitivity. Taking into account the fact that other periodontal red complex bacteria express PFOR, AMX could serve as a new selective adjunctive treatment for periodontal disease.


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Available for download on Thursday, May 07, 2026


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