Scytalidium dimidiatum causing recalcitrant subcutaneous lesions produces melanin

R. Morris-Jones, S. Youngchim, J. M. Hextall, B. L. Gomez, S. D. Morris-Jones, R. J. Hay, A. Casadevall, J. D. Nosanchuk, A. J. Hamilton

Research output: Contribution to journalResearch Articlepeer-review

37 Scopus citations


Scytalidium dimidiatum is a pigmented dematiaceous coelomycete that typically causes chronic superficial skin diseases and onychomycosis, as well as deeper infections, such as subcutaneous abscesses, mycetoma, and even fungemia in immunocompromised patients. A second species, Scytalidium hyalinum, has hyaline hyphae and arthroconidia and is considered by some authors to be an albino mutant of S. dimidiatum. This study aimed to confirm the presence of melanin or melanin-like compounds (which have been previously implicated in the virulence of other fungal pathogens) in S. dimidiatum from a patient with multiple subcutaneous nodules. Treatment of the hyphae and arthroconidia with proteolytic enzymes, denaturant, and concentrated hot acid yielded dark particles, which were stable free radicals, consistent with their identification as melanins. Extracted melanin particles from S. dimidiatum cultures were labeled by melanin-binding monoclonal antibodies (MAbs) from Sporothrix schenckii, Aspergillus fumigatus, and Cryptococcus neoformans. Lesional skin from the patient infected with S. dimidiatum contained fungal cells that were labeled by melanin-binding MAbs, and digestion of the tissue yielded dark particles that were also reactive. S. hyalinum was also subjected to the melanin extraction protocol, but no dark particles were yielded.

Original languageEnglish (US)
Pages (from-to)3789-3794
Number of pages6
JournalJournal of Clinical Microbiology
Issue number8
StatePublished - Aug 2004
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Microbiology (medical)


Dive into the research topics of 'Scytalidium dimidiatum causing recalcitrant subcutaneous lesions produces melanin'. Together they form a unique fingerprint.

Cite this