Author ORCID Identifier
https://orcid.org/0000-0002-0359-7362
Date of Graduation
5-2026
Document Type
Dissertation (PhD)
Program Affiliation
Microbiology and Infectious Diseases
Degree Name
Doctor of Philosophy (PhD)
Advisor/Committee Chair
Michael Lorenz, PhD
Committee Member
Danielle Garsin, PhD
Committee Member
Theresa M. Koehler, PhD
Committee Member
Ambro van Hoof, PhD
Committee Member
Christian Perez, PhD
Committee Member
Catherine Denicourt, PhD
Abstract
Candida auris is an emerging multidrug-resistant opportunistic fungal pathogen. It
poses a significant threat to immunocompromised patients and those with prolonged stays in
healthcare facilities. C. auris spreads rapidly in health care facilities through enhanced
colonization of skin and abiotic surfaces. The genetic factors contributing to this ability and to
the virulence, drug resistance, and stress-tolerant nature of C. auris are largely unknown.
Current animal models of C. auris infections are not well standardized and report conflicting
results. Additional animal models of virulence are needed, especially those amenable to high-
throughput analysis. The nematode Caenorhabditis elegans has been validated as an effective
tool for studying multiple fungal and bacterial pathogens. In this thesis, I describe a C. elegans
infection model in which C. auris is lethal to worms with kinetics similar to those observed for
C. albicans. However, C. auris does not form hyphae, indicating distinct virulence
mechanisms. Furthermore, a mutant auxotrophic for adenosine (ade2Δ) is avirulent in this
model, demonstrating that the nematode can discriminate between virulent and avirulent
strains. The C. elegans model also recapitulates strain-to-strain variability in virulence
observed in mouse models. In addition, I have adapted a live/dead staining methodology using
SYTOX Orange to enable a high-throughput assay suitable for analyzing multiple strains or
genetic mutants. Finally, I used this high-throughput assay to screen an insertion mutant library
viifor avirulent mutants and identified several potential novel virulence factors. This model has
significant advantages relative to other invertebrate virulence models for C. auris and is a
beneficial complement to the more challenging and variable murine models.
Recommended Citation
Martinez, Melissa, "A tractable nematode model for the emerging fungal pathogen, Candida auris" (2026). Dissertations & Theses (Open Access). 1506.
https://digitalcommons.library.tmc.edu/utgsbs_dissertations/1506
Keywords
Candida auris, Candidozyma auris, Caenorhabditis elegans, Animal Model