Scedosporium

Microbiology

• Septate hyaline mold
• Macroscopic appearance
  • Colony grows rapidly, with wooly to cottony texture, a white surface that browns as it ages, and a pale reverse with brownish black zones.
• Microscopic appearance
  • Septate, hyaline hyphae with annellide conidiophores that are simple or branched
  • Onidia are unicellular, obovoid, and pale brown
  • Sometimes has a Graphium state where conidiophores are bound together
  • Brown cleistothecia may be present after 2-3 weeks of incubation (looks like a Pacman vomiting out conidia)

Epidemiology

• Found in rural soils, polluted waters, compost, cattle manure, and bird poop, as well as colonizing the respiratory tract
• Present worldwide
• Affects primarily the immunocompromised, though can cause localized infections in immunocompetent as well

Clinical Presentation

• Colonization of airways, especially in bronchiectasis
• Pseudallescheria boydii (Scedosporium apio­spermum) can cause mycetoma, and also pseudallescheriasis/scedosporiosis of lung, bone, joint, CNS. Rare sites of involvement include sinusitis, keratitis, endophthalmitis, skin and soft tissue infections, prostatitis, and endocarditis.
• Scedosporium prolificans usually causes localized infections in immunocompetent patients (bone and joint, eye, wounds, onychomycosis). In immunocompromised patients (e.g. neutropenia from chemotherapy), can disseminate and involve skin, lung, muscle, endophthalmitis

Diagnosis

• With culture, though may represent colonization if recovered from a respiratory specimen.

Management

• S. apiopsermum is treated with voriconazole or amphotericin B. However, S. prolificans is extremely resistant to antifungals including amphotericin