Scedosporium prolificans

Synonym: Scedosporium inflatum

Colonies are rapid growing, flat, spreading, olive-grey to black and have a suede-like to downy surface texture. Conidia are borne in small groups on distinctive basally swollen, flask-shaped annellides, which occur singly or in clusters along the vegetative hyphae. Conidia are single-celled, hyaline to pale-brown, ovoid to pyriform, 2-5 x 3-13 um (average 3.4-5.3 um) in size, and have smooth thin walls.

Scedosporium prolificans is distinguished from other members of the genus, in particular, the human pathogen S. apiospermum, by having basally swollen (inflated), flask-shaped annellides, slower colony development on nutrient agar media, and by not growing on media containing cycloheximide (actidione).

Conidiophores (annellides) and conidia of Scedosporium prolificans.

MIC data is limited.  Antifungal susceptibility testing of individual strains is recommended.

Clinical significance:

The spectrum of clinical manifestations caused by Scedosporium prolificans are similar to that described above for Pseudallescheria boydii. Disseminated disease has been reported in immunosuppressed patients especially those with prolonged neutropenia and post-transplantation therapy. Colonization of the external ear, paranasal sinuses and lung, including "fungus ball" have been reported. Cases of onychomycosis and mycotic keratitis have also been documented. However, localized invasive infections, especially septic arthritis and osteomyelitis following penetrating injuries to joints, are now an emerging clinical problem, accounting for 80% of the reported cases. Culture identification is important, because this fungus is often resistant to antifungal therapy and treatment may require surgical intervention.

Mycosis: Pseudallescheriasis and Scedosporium infection

Further reading:

De Hoog G.S. and J Guarro. 1995. Atlas of clinical fungi. Centraalbureau voor Schimmelcultures, Baarn and Delft, The Netherlands.

Kwon-Chung, K.J. and J.E. Bennett. 1992. Medical Mycology. Lea & Febiger, Philadelphia and London.