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.
","abstract_html":"<p><em>Candida auris</em> is an emerging multidrug-resistant opportunistic fungal pathogen. It</p> <p>poses a significant threat to immunocompromised patients and those with prolonged stays in</p> <p>healthcare facilities. <em>C. auris</em> spreads rapidly in health care facilities through enhanced</p> <p>colonization of skin and abiotic surfaces. The genetic factors contributing to this ability and to</p> <p>the virulence, drug resistance, and stress-tolerant nature of <em>C. auris</em> are largely unknown.</p> <p>Current animal models of <em>C. auris</em> infections are not well standardized and report conflicting</p> <p>results. Additional animal models of virulence are needed, especially those amenable to high-</p> <p>throughput analysis. The nematode <em>Caenorhabditis elegans</em> has been validated as an effective</p> <p>tool for studying multiple fungal and bacterial pathogens. In this thesis, I describe a <em>C. elegans</em></p> <p>infection model in which <em>C. auris</em> is lethal to worms with kinetics similar to those observed for</p> <p><em>C. albicans</em>. However, <em>C. auris</em> does not form hyphae, indicating distinct virulence</p> <p>mechanisms. Furthermore, a mutant auxotrophic for adenosine (<em>ade2</em>Δ) is avirulent in this</p> <p>model, demonstrating that the nematode can discriminate between virulent and avirulent</p> <p>strains. The <em>C. elegans</em> model also recapitulates strain-to-strain variability in virulence</p> <p>observed in mouse models. In addition, I have adapted a live/dead staining methodology using</p> <p>SYTOX Orange to enable a high-throughput assay suitable for analyzing multiple strains or</p> <p>genetic mutants. Finally, I used this high-throughput assay to screen an insertion mutant library</p> <p>viifor avirulent mutants and identified several potential novel virulence factors. This model has</p> <p>significant advantages relative to other invertebrate virulence models for <em>C. auris</em> and is a</p> <p>beneficial complement to the more challenging and variable murine models.</p>","abstract_has_math":false,"creators":["Martinez, Melissa","https://orcid.org/0000-0002-0359-7362
"],"institution":null,"degree_name":"Doctor of Philosophy (PhD)","degree_level":"Dissertation (PhD)","degree_discipline":null,"degree_department":null,"school":null,"contributors":["Michael Lorenz, PhD","Danielle Garsin, PhD","Theresa M. Koehler, PhD"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2026,"date_issued":"2026-05-01T07:00:00Z","date_published":"2026-05-01T07:00:00Z","updated_at":"2026-07-24T05:50:47Z","subjects":["Candida auris","Candidozyma auris","Caenorhabditis elegans","Animal Model","Animal Experimentation and Research","Microbiology","Pathogenic Microbiology"],"languages":[],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://digitalcommons.library.tmc.edu/utgsbs_dissertations/1506","outbound_label":"Repository record","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Michael Lorenz, PhD","Danielle Garsin, PhD","Theresa M. Koehler, PhD"]},{"key":"dc:creator","label":"Author","values":["Martinez, Melissa","https://orcid.org/0000-0002-0359-7362
"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.available","label":"Dc Date Available","values":["2026-02-24T08:00:00Z"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Dissertation (PhD)"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Doctor of Philosophy (PhD)"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Candida auris","Candidozyma auris","Caenorhabditis elegans","Animal Model","Animal Experimentation and Research","Microbiology","Pathogenic Microbiology"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["https://digitalcommons.library.tmc.edu/utgsbs_dissertations/1506"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["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.
"]},{"key":"dc:title","label":"Title","values":["A tractable nematode model for the emerging fungal pathogen, Candida auris"]}]}],"canonical_facts":{"dc:contributor":["Michael Lorenz, PhD","Danielle Garsin, PhD","Theresa M. Koehler, PhD"],"dc:creator":["Martinez, Melissa","https://orcid.org/0000-0002-0359-7362
"],"dc:date.available":["2026-02-24T08:00:00Z"],"dc:description.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.
"],"dc:identifier":["https://digitalcommons.library.tmc.edu/utgsbs_dissertations/1506"],"dc:subject":["Candida auris","Candidozyma auris","Caenorhabditis elegans","Animal Model","Animal Experimentation and Research","Microbiology","Pathogenic Microbiology"],"dc:title":["A tractable nematode model for the emerging fungal pathogen, Candida auris"],"thesis:degree_level":["Dissertation (PhD)"],"thesis:degree_name":["Doctor of Philosophy (PhD)"]},"updated_at":"2026-07-24T05:50:47Z"}