Scedosporium aurantiacum

Colonies are fast growing, greyish-white and suede-like to downy.  All isolates produce a light yellow diffusible pigment on PDA after a few days incubation. Conidiogenous cells and conidia are similar in shape and size to S. apiospermum, and the two can best be distinguished by genetic analysis (see Gilgado et al. 2005). Conidiogenous cells arising from undifferentiated hyphae are cylindrical to slightly flask-shaped, producing slimy heads of one-celled , smooth-walled, subhyaline, obovoid or sub-cylindrical conidia. 5-14 x 2-5 um. Erect synnemata (a Graphium synanamorph) may be present in some isolates, but the teleomorph is unknown. Optimum temperature for growth 37-40C, max 45C. RG-2 organism.

Culture of Scedosporium aurantiacum.

Conidiophores and conidia of S. aurantiacum.

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

Clinical significance:

S. apiospermum and S. aurantiacum appear to be common soil fungi capable of causing a spectrum of diseases similar in terms of variety and severity to those caused by Aspergillus collectively referred to as Pseudallescheriasis. The vast majority of infections are mycetomas, the remainder include infections of the eye, ear, central nervous system, internal organs and more commonly the lungs.

Mycosis: Pseudallescheriasis and Scedosporium infection

Further reading:

Gilgado, F., J. Cano, J. Gene and J. Guarro. 2005. Molecular phylogeny of the Pseudallescheria boydii species complex: proposal of two new species. J. Clin. Microbiol. 43:4930-4942.

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.