DESCRIPTIONS OF MEDICAL FUNGI
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Descriptions of Medical Fungi 179<br />
Scedosporium Sacc. ex Castell. & Chalm.<br />
The taxonomy of this genus has been subject to change on the basis of sequence data;<br />
Scedosporium apiospermum and Scedosporium boydii (formerly Pseudallescheria<br />
boydii) are now recognised as separate species and along with S. aurantiacum are<br />
the principal human pathogens (Lackner et al. 2014a). The majority of infections<br />
are mycetomas, the remainder include infections of the eye, ear, central nervous<br />
system, internal organs and more commonly the lungs. Scedosporium dehoogii and<br />
S. minutispora are mainly isolated from environmental samples and have been rarely<br />
reported from clinical cases (Gilgado et al. 2005, Rainer and de Hoog 2006, Cortez et<br />
al. 2008, Kaltseis et al. 2009).<br />
Scedosporium prolificans has been transferred to the genus Lomentospora. L. prolificans<br />
is phylogenetically and morphologically distinct from the remaining Scedosporium<br />
species (Lennon et al. 1994, Lackner et al. 2014a).<br />
Morphological identification of Scedosporium species has become increasingly<br />
unreliable and molecular identification methods are now recommended. The conidial<br />
states of S. apiospermum and S. boydii are morphologically indistinguishable; although<br />
the latter is homothallic and produces ascocarps. S. aurantiacum also exhibits similar<br />
conidial morphology but most strains produce a pale to bright yellow diffusible pigment<br />
on potato dextrose agar.<br />
Molecular Identification: Recommended genetic markers are ITS and β-tubulin<br />
(Lackner et al. 2012a).<br />
MALDI-T<strong>OF</strong> MS: A comprehensive ‘in-house’ database of reference spectra allows<br />
accurate identification of Scedosporium and Lomentospora species (Lau et al. 2013,<br />
Sitterlé et al. 2014).<br />
References: McGinnis (1980), Domsch et al. (1980), McGinnis et al. (1982), Campbell<br />
and Smith (1982), Rippon (1988), de Hoog et al. (2000, 2015), Gilgado et al. (2005),<br />
Rainer and de Hoog (2006), Guarro et al. (2006), Lackner et al. (2014a).<br />
Scedosporium apiospermum (Saccardo) Castellani and Chalmers<br />
Synonymy: Pseudallescheria apiosperma Gilgado, Gené, Cano & Guarro<br />
RG-2 organism.<br />
Morphological Description: Colonies are fast growing, greyish-white, suede-like<br />
to downy with a greyish-black reverse. Numerous single-celled, pale-brown, broadly<br />
clavate to ovoid conidia, 4-9 x 6-10 µm, rounded above with truncate bases are<br />
observed. Conidia are borne singly or in small groups on elongate, simple or branched<br />
conidiophores or laterally on hyphae. Conidial development can be described as<br />
annellidic, although the annellations (ring-like scars left at the apex of an annellide after<br />
conidial secession) are extremely difficult to see. Erect synnemata may be present in<br />
some isolates. Optimum temperature for growth is 30-37 O C.