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Susceptibility of species within the Sporothrix schenckii complex to a panel of killer yeasts
Cheila Denise Ottonelli Stopiglia1, Daiane Heidrich, Julia Medeiros Sorrentino
1Programa de Pós-Graduação em Medicina: Ciências Médicas, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil; Departamento de Microbiologia, Imunologia e Parasitologia, ICBS, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil.
Abstract:
The Sporothrix schenckii complex is the etiologic agent of sporotrichosis, a subacute or chronic mycosis which can affect humans and animals. Killer yeasts have been used in the medical field for development of novel antimycotics and biotyping of pathogenic fungi. The action of 18 killer yeasts on the growth of 88 characterized S. schenckii, Sporothrix globosa, Sporothrix brasiliensis, and Sporothrix mexicana clinical and environmental isolates was evaluated. Killer studies were performed on Petri dishes containing cheese black starch agar. The yeasts Candida catenulata (QU26, QU31, QU127, LV102); Trichosporon faecale (QU100); Trichosporon japonicum (QU139); Kluyveromyces lactis (QU30, QU99, QU73); Kazachstania unispora (QU49), Trichosporon insectorum (QU89), and Kluyveromyces marxianus (QU103) showed activity against all strains of the S. schenckii complex tested. Observation by optical microscopy of S. brasiliensis 61 within the inhibition haloes around the colonies of the killer yeasts QU100, QU139, and LV102 showed that there was no conidiation, but there was hyphal proliferation. The toxins were fungistatic against S. brasiliensis 61. There was no difference in susceptibility to the toxins among the S. schenckii species complex. Further investigations are necessary to clearly establish the mechanism of action of the toxins.
Insights
Certain killer yeasts exhibit antifungal activity against the Sporothrix schenckii complex, the cause of sporotrichosis. This study evaluated 18 killer yeasts, finding several effective against all tested S. schenckii species, suggesting potential for novel antimycotic development.
Area of Science:
- Medical Mycology
- Antimicrobial Discovery
- Fungal Pathogenesis
Background:
- The Sporothrix schenckii complex causes sporotrichosis, a significant human and animal mycosis.
- Killer yeasts are recognized for their potential in developing new antimycotics and for fungal biotyping.
Purpose of the Study:
- To assess the efficacy of 18 killer yeasts against clinical and environmental isolates of the Sporothrix schenckii complex.
- To investigate the impact of killer yeast toxins on the growth and morphology of Sporothrix species.
Main Methods:
- Screening of 18 killer yeast strains against 88 characterized isolates of S. schenckii, S. globosa, S. brasiliensis, and S. mexicana.
- Inhibition zone assays performed on cheese black starch agar.
- Microscopic observation of fungal morphology within inhibition zones.
Main Results:
- Several killer yeasts, including Candida catenulata, Trichosporon faecale, Trichosporon japonicum, Kluyveromyces lactis, Kazachstania unispora, Trichosporon insectorum, and Kluyveromyces marxianus, demonstrated activity against all S. schenckii complex strains.
- Microscopic analysis revealed inhibited conidiation and hyphal proliferation in S. brasiliensis, indicating fungistatic effects.
- No significant differences in susceptibility were observed among the S. schenckii species complex.
Conclusions:
- Specific killer yeasts possess antifungal properties effective against the entire Sporothrix schenckii complex.
- These findings support the potential use of killer yeast toxins as a basis for novel antimycotic agents against sporotrichosis.
- Further research is warranted to elucidate the precise mechanisms of action of these antifungal toxins.
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