Sporothrix brasiliensis Atypical Dimorphism in Tissue.

Area of Science:

• Mycology
• Infectious Diseases
• Pathology

Background:

• Sporotrichosis is an emerging zoonotic infection caused by Sporothrix brasiliensis.
• The fungus is typically found in yeast form in host tissues.
• Immunocompromised individuals are particularly susceptible.

Purpose of the Study:

• To report a rare morphological phenomenon of Sporothrix brasiliensis in human biopsies.
• To investigate the implications of atypical fungal dimorphism in sporotrichosis diagnosis.
• To highlight evolving diagnostic challenges in fungal infections.

Main Methods:

• Case study of three immunocompromised patients.
• Identification of Sporothrix brasiliensis using calmodulin gene sequencing.
• Phylogenetic analysis for species-level classification.
• Direct examination and histopathology of patient biopsies.

Main Results:

• Three immunocompromised patients exhibited simultaneous yeast and mycelial forms of S. brasiliensis in biopsies.
• This polymorphic fungal morphology is previously unreported in human sporotrichosis cases.
• Atypical dimorphism may be linked to local tissue conditions like oxygen and temperature.

Conclusions:

• The recognition of polymorphic fungal forms is crucial for accurate sporotrichosis diagnosis.
• Atypical dimorphism in S. brasiliensis presents significant diagnostic implications for pathologists and mycologists.
• This finding underscores the evolving histopathological challenges in managing fungal infections.