Mucor germinans, a novel dimorphic species resembling Paracoccidioides in a clinical sample: questions on ecological strategy
- Author: mycolabadmin
- 7/2/2024
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Summary
Researchers discovered a new fungus called Mucor germinans that infected a cancer patient’s lungs and appeared as yeast cells rather than the typical thread-like fungal structures. This is unusual because Mucor infections normally show filamentous hyphae, and the yeast-like appearance made it look like a different fungus, potentially delaying correct diagnosis and treatment. The study shows that this fungus can change forms depending on temperature and other conditions, and identifying it requires checking for multiple nuclei in the cells to distinguish it from other similar-looking yeasts.
Background
Mucormycosis is an aggressive opportunistic infection with high morbidity and mortality in immunocompromised patients. Mucorales infections are typically characterized by non-septate hyphae, but yeast-like forms have been occasionally reported in clinical specimens. Dimorphism in Mucorales has primarily been studied in Mucor circinelloides.
Objective
To characterize a novel dimorphic mucoralean fungus isolated from sputum of a patient with Burkitt lymphoma that presented as yeast-like cells resembling Paracoccidioides. To investigate the dimorphic properties and temperature-dependent morphological transformations in comparison with environmental Mucor strains.
Results
A novel dimorphic Mucor species (Mucor germinans sp. nov.) was identified and formally described. The species produced multinucleate yeast-like cells at elevated temperatures, resembling Paracoccidioides. Temperature, oxygen availability, and glucose concentration all stimulated yeast cell conversion. M. germinans showed sensitivity to amphotericin B but resistance to several azoles.
Conclusion
Yeast-like cells in Mucorales are an overlooked diagnostic feature that can be confused with other fungal pathogens, potentially delaying treatment. Multinucleate status is a useful diagnostic parameter to distinguish mucoralean infections from mononucleate yeasts. Recognition of dimorphism in Mucor species is critical for accurate clinical diagnosis and appropriate antifungal therapy selection.
- Published in:mBio,
- Study Type:Case Report and Comparative Study,
- Source: PMID: 38953355; DOI: 10.1128/mbio.00144-24