EPIDEMIOLOGY AND BIOLOGY OF SCEDOSPORIUM SPECIES

Scedosporium spp. are filamentous fungus which induces an increasingly wide spectrum of diseases affecting immunosuppressed and healthy subj ects. The clinical spectrum of diseases is well known, but very little is known about its epidemiology and biology. The taxonomic position o f the Scedosporium species is complex. The two species, Scedosporium a piospermum and Scedosporium prolificans, have different mycological an d clinical features, and require specific treatments. The great variet y of ecological niches of the fungus accounts for the various modes of host contamination (inhalation and trauma), and differ from Aspergill us by the relative frequency of mycetomas. Basic physiological informa tion concerning fungal nutrition has now been established, and it is k nown to play a role in the development of the sexual state of the fung us (Pseudallescheria boydii). In contrast, little is known about the h ost response to the fungus, no reliable serological procedures are ava ilable, and very few studies have been conducted concerning molecular aspects. In this paper, we review the knowledge concerning the epidemi ology and biology of the two species of Scedosporium. Pseudallescheria boydii is an increasingly frequent pathogen which will tend to become more frequent in the future due to its widespread distribution in nat ural substrates and the increasing use of immunosuppressive drugs. It will therefore require more extensive biological studies.