DESCRIPTIONS OF MEDICAL FUNGI

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Descriptions of Medical Fungi
Hortaea werneckii (Horta) Nishimura & Miyaji
Synonymy: Phaeoannellomyces werneckii (Horta) McGinnis & Schell; Exophiala
werneckii (Horta) v. Arx; Cladosporium werneckii Horta.
Hortaea werneckii is a common saprophytic fungus believed to occur in soil, compost,
humus and on wood in humid tropical and subtropical regions and is the causative
agent of tinea nigra in humans. RG-1 organism.
Morphological Description: Colonies are slow growing, initially mucoid, yeast-like
and shiny-black. However with age they develop abundant aerial mycelia and become
dark olivaceous in colour. Microscopically, colonies consist of brown to dark olivaceous,
septate hyphal elements and numerous two-celled, pale brown, cylindrical to spindleshaped
yeast-like cells that taper towards the ends to form an annellide. Most yeastlike
cells also have prominent darkly-pigmented septa. Annellides may also arise from
the hyphae. Conidia are one to two-celled, cylindrical to spindle-shaped, hyaline to
pale brown and usually occur in aggregated masses. Chlamydospores also present.
Key Features: Hyphomycete, two-celled yeast-like cells producing annelloconidia.
Molecular Identification: An ITS-primer specific for H. werneckii was developed by
Abliz et al. (2003). ITS sequencing can also assist identification.
References: Mok (1982), McGinnis (1980), McGinnis et al. (1985), Rippon (1988), de
Hoog et al. (2000), Abliz et al. (2003), Ng et al. (2005).
Antifungal Susceptibility: H. wernickii (Ng et al. 2005, Formoso et al. 2015); MIC
µg/mL.
No. 64
AmB 6 1 1 1 1 2
FLU 6 2 1 3
VORI 6 2 1 3
POSA 4 2 2
ITRA 8 2 2 2 2
a
20 µm
b
Hortaea werneckii (a) culture and (b) conidia.