DESCRIPTIONS OF MEDICAL FUNGI

Descriptions of Medical Fungi 163
Quambalaria cyanescens
Synonymy: Sporothrix cyanescens de Hoog & de Vries.
Cerinosterus cyanescens (de Hoog & de Vries) R.T. Moore
The genus Quambalaria contains five species, including Q. cyanescens, Q. pitereka,
Q. eucalypti, Q. coyrecup and Q. simpsonii. Q. cyanescens is a hyaline basidiomycete
isolated from a broad range of ecological niches, including air, soil, and insect larvae as
well as in association with diverse plant sources, including Corymbia and Eucalyptus
species from Australia. Q. cyanescens appears to be an emerging opportunistic
pathogen in immunocompromised or debilitated individuals. It has been isolated from
human skin and subcutaneous infections, blood, nosocomial infections in patients with
pneumonia, peritonitis and invasive pulmonary infection (Jackson et al. 1990, Tambini
et al. 1996, Schmidt et al. 2000, Kuan et al. 2015).
RG-1 organism.
Morphological Description: Colonies are restricted, farinose or velvety, often compact
and somewhat cerebriform, snow-white, and later often exuding a pH-dependent, deep
blue/violet pigment into the agar. Conidiogenous cells are undifferentiated, cylindrical,
of variable size (1.5-3.0 µm wide), apically with a cluster of small denticles, the cluster
often repeatedly proliferating and forming similar clusters. Conidia are hyaline, smoothwalled
or finely verrucose, obovoidal, 3-4 µm long, somewhat larger (3.5-6.5 µm long)
when bearing secondary conidia.
Molecular Identification: ITS and D1/D2 sequencing recommended.
Key Features: Q. cyanescens is similar to Sporothrix, but the conidial scars are
very small and cultures are thin and fragile. In fresh cultures the diffusible pigment
is characteristic. Sporothrix schenckii forms tough colonies, which finally become
blackish-brown.
References: de Hoog and de Vries (1973), de Beer et al. (2006), Simpson (2000), de
Hoog et al. (2015).
b
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10 µm
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Quambalaria cyanescens (a) culture, (b) conidiogenous cells with small
denticles and conidia, and (c) mature conidium bearing secondary conidia.