DESCRIPTIONS OF MEDICAL FUNGI

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Descriptions of Medical Fungi
Sporothrix schenckii complex
It is now recognised that Sporothrix schenckii is a species complex of five distinct
species: S. schenckii sensu strictu, S. brasiliensis, S. globosa, S. mexicana and S.
luriei (Marimon et al. 2007, Romeo et al. 2011, Barros et al. 2011, Oliveira et al. 2014,
Zhang et al. 2015b). RG-2 organism.
Sporothrix schenckii complex is a dimorphic fungus and has a worldwide distribution,
particularly in tropical and temperate regions. It is commonly found in soil and on decaying
vegetation and is a well-known pathogen of humans and animals. Sporotrichosis is
primarily a chronic mycotic infection of the cutaneous or subcutaneous tissues and
adjacent lymphatics characterised by nodular lesions which may suppurate and
ulcerate. Infections are caused by the traumatic implantation of the fungus into the
skin, or very rarely, by inhalation into the lungs. Secondary spread to articular surfaces,
bone and muscle is not infrequent, and the infection may also occasionally involve the
central nervous system, lungs or genitourinary tract.
Sporothrix schenckii Hektoen & Perkins
Morphological Description: Colonies at 25 O C, are slow growing, moist and glabrous,
with a wrinkled and folded surface. Some strains may produce short aerial hyphae
and pigmentation may vary from white to cream to black. Conidiophores arise at right
angles from thin septate hyphae and are usually solitary, erect and tapered toward the
apex. Conidia are formed in clusters on tiny denticles by sympodial proliferation at the
apex of the conidiophore, their arrangement often suggestive of a flower. As the culture
ages, conidia are subsequently formed singly along the sides of both conidiophores
and undifferentiated hyphae. Conidia are ovoid or elongated, 3-6 x 2-3 µm, hyaline,
one-celled and smooth-walled. In some isolates, solitary, darkly-pigmented, thickwalled,
one-celled, obovate to angular conidia may be observed along the hyphae. On
brain heart infusion (BHI) agar containing blood at 37 O C, colonies are glabrous, white
to greyish-yellow and yeast-like consisting of spherical or oval budding yeast cells.
Molecular Identification: DNA sequencing using ITS, D1/D2, β-tubulin, calmodulin
and chalcone synthase genes is recommended for species identification (Marimon
et al. 2007, Romeo et al. 2011, Barros et al. 2011, Oliveira et al. 2014, Zhang et al.
2015b).
MALDI-TOF MS: Oliverira et al. (2015) established a MALDI-TOF protocol and
reference database for the identification of Sporothrix species.
Key Features: Hyphomycete characterised by thermal dimorphism and clusters of
ovoid, denticulate conidia produced sympodially on short conidiophores.
References: McGinnis (1980), Domsch et al. (1980), Rippon (1988), de Hoog et al.
(1985, 2000, 2015).
Antifungal Susceptibility: S. schenckii variable data for amphotericin B and azoles;
testing of individual strains recommended (Alvarado-Ramirez and Torres-Rodriguez
2007, Marimon et al. 2008, Silveira et al. 2009, Oliveira et al. 2011, Ottonelli Stopiglia
et al. 2014, Rodrigues et al. 2014, Australian National data); MIC µg/mL.
Antifungal Range MIC 90
Antifungal Range MIC 90
AmB 0.03->16 >16 POSA 0.03->16 8
ITRA 0.03->16 >16 VORI 0.125->16 >16
TERB 0.03-1 0.5