Return to index

Scedosporium sp.

Mitosporic fungi. Hyphomycetes. Teleomorph (sexual state): Pseudallescheria.
Scedosporium species comprise a small proportion of the fungal biota. This genus is distantly related to Sporothrix, Exophiala, and Scopulariopsis. Two species have health effects which can be serious, even fatal: Scedosporium apiospermum and Scedosporium prolificans. These organisms have a surplus of past names. S. apiospermum was formerly called Monosporium apiospermum, while S. prolificans was formerly called S. inflatum. In addition, the sexual phase of S. apiospermum, now called Pseudallescheria boydii, has been called Allescheria boydii and Petriellidium boydii. To confuse things even further, S. apiospermum has yet another asexual coremial form called Graphium eumorphum, syn. Graphium fructicola, but is usually reported as the "Graphium state of Scedosporium apiospermum." Health effects are many, particularly with regard to Scedosporium apiospermum. There have been many reports of opportunistic infections, including white grain mycetoma which occurs world-wide. Other systemic infections may involved the central nervous system, usually after severe local trauma or after aspiration of polluted water. In addition, this organism may cause an invasive sinusitis, pneumonia, or allergic reactions in the lungs. Ophthalmic cases have been reported. What makes these infections very serious is the fact that this organism is very resistant to most of the antifungal medications available. Scedosporium prolificans has been associated with subcutaneous lesions after trauma with thorns or splinters. In immunocompromised patients or transplantation patients fatal dissemination may occur. Fortunately, these organisms are infrequently found growing on environmental surfaces. No information is available regarding toxicity. Allergenicity has not been well studied. May be identified on surfaces by tape lifts, tease mounts from bulk samples, and in air by culturable (Andersen) samples. Scedosporium apiospermum has somewhat distinctive spores which could be counted on spore trap samples if the presence of this genus has already been demonstrated (for example, on tape lifts). Natural habitat includes soil, polluted water, and manure.
Definitions | References | Commentary