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Updated: Feb 4, 2026
Infecting Mice with Malassezia spp. to Study the Fungus-Host Interaction
Published on: November 6, 2019
Drosophila melanogaster as a model for the study of Malassezia pachydermatis infections
Simone Merkel1, Daiane Heidrich2, Chris Krebs Danilevicz1
1Postgraduate Program in Biological Sciences: Pharmacology and Therapeutics, Federal University of Rio Grande do Sul (UFRGS), Porto Alegre, Brazil.
Abstract:
Malassezia pachydermatis is a yeast that is commonly found in the skin of most animals. Changes in the physical, chemical or immunological processes of the skin may render the host more susceptible to the yeast, which then may cause otitis, dermatitis or, less often, systemic infection. We tested the pathogenicity of M. pachydermatis in wild-type (WT) and Toll-deficient Drosophila melanogaster. Flies were inoculated in the thorax with a needle previously dipped in inoculum concentrations ranging from 103 and 107 yeast cells/mL. After infection, flies were housed at 29 °C and mortality was evaluated daily until day seven. WT flies were resistant to the infection, whereas Toll-deficient flies showed inoculum-dependent mortality rates. Fungal burden, assessed by histopathological analysis and by counting the number of colony-forming units of dead flies, corroborated the results. The D. melanogaster model is a promising minihost model for future large-scale studies of virulence mechanisms and antifungal drug activity in malasseziosis.
Insights
Malassezia pachydermatis causes infections when host defenses are compromised. Toll-deficient fruit flies (Drosophila melanogaster) showed increased mortality, indicating this model
Area of Science:
- Mycology
- Immunology
- Infectious Diseases
Background:
- Malassezia pachydermatis is a common skin yeast in animals.
- Skin condition changes can increase susceptibility to Malassezia, leading to otitis, dermatitis, or systemic infections.
Purpose of the Study:
- To evaluate the pathogenicity of Malassezia pachydermatis.
- To assess the utility of Drosophila melanogaster as a model organism for studying malasseziosis.
Main Methods:
- Wild-type and Toll-deficient Drosophila melanogaster were inoculated with varying concentrations of Malassezia pachydermatis.
- Mortality was monitored daily for seven days.
- Fungal burden was assessed via histopathology and colony-forming unit counts.
Main Results:
- Wild-type flies exhibited resistance to Malassezia infection.
- Toll-deficient flies demonstrated inoculum-dependent mortality.
- Histopathological and CFU analyses confirmed increased fungal burden in susceptible flies.
Conclusions:
- Drosophila melanogaster lacking Toll pathway components are susceptible to Malassezia pachydermatis.
- The Drosophila model offers a promising platform for large-scale virulence and antifungal drug studies in malasseziosis.
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