Degree Name
MS (Master of Science)
Program
Biology
Date of Award
8-2026
Committee Chair or Co-Chairs
Sean J. Fox
Committee Members
Ranjan Chakraborty, Jennifer Hall
Abstract
Chromobacterium violaceum and Raoultella planticola are understudied soil-associated bacteria with potential relevance to human health. Although Raoultella species are increasingly reported in nosocomial infections, their pathogenicity remains poorly understood. In contrast, C. violaceum is well-characterized and produces the secondary metabolite violacein. This study examined interactions between R. planticola and C. violaceum, focusing on violacein production, antibiotic susceptibility, and growth effects in vitro and in vivo. Kirby-Bauer testing showed identical antibiotic susceptibility, while coculture demonstrated selective violacein production. Biofilm growth by both bacteria was ratio dependent, with biomass varying based on the relative starting ratios. Extracted violacein inhibited Gram-positive bacteria and fungi, but not Gram-negative bacteria. In a Caenorhabditis elegans model, coinfection caused minimal microbial burden disruption. Overall, these findings suggest condition-dependent interactions rather than a purely synergistic relationship. This study provides for a better understanding of polymicrobial behavior and the potential ecological and clinical significance of Chromobacterium and Raoultella.
Document Type
Thesis - embargo
Recommended Citation
Miller, Katelyn, "Shades of Survival: Polymicrobial Interactions and Violacein Modulation of Chromobacterium violaceum with Raoultella planticola" (2026). Electronic Theses and Dissertations. Paper 4755. https://dc.etsu.edu/etd/4755
Copyright
Copyright by the authors.
