Hortaea werneckii
Synonyms:
Cladosporium werneckii; Exophiala werneckii; Phaeoannellomyces werneckii.
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.
Conidia of Hortaea werneckii
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 spindle-shaped yeast-like cells that taper towards the ends to form an annellide. Most yeast-like 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.
| Antifungal susceptibility: Hortaea werneckii (Australian national data); MIC µg/mL | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| No | ≤0.03 | 0.06 | 0.125 | 0.25 | 0.5 | 1 | 2 | 4 | 8 | 16 | 32 | ≥64 | |
| AmB | 7 | 1 | 1 | 1 | 2 | 2 | |||||||
| FLU | 7 | 2 | 1 | 4 | |||||||||
| VORI | 7 | 2 | 1 | 3 | 1 | ||||||||
| POSA | 5 | 2 | 2 | 1 | |||||||||
| ITRA | 9 | 2 | 2 | 2 | 3 | ||||||||
References
- Abliz, P., Fukushima, K., Takizawa, K., et al. (2003) Rapid identification of the genus Fonsecaea by PCR with specific oligonucleotide primers. Journal of Clinical Microbiology, 41, 873-876.de Hoog, G.S., Guarro, J., Gene, J., et al. (2015) Atlas of Clinical Fungi (Version 4.1.2). Centraalbureau voor Schimmelcultures, Utrecht, The Netherlands.
- Formoso, A., Heidrich, D., Felix, C.R. et al. (2015) Enzymatic activity and susceptibility to antifungal agents of Brazilian environmental isolates of Hortaea werneckii. Mycopathologia,180, 345-352.
- McGinnis, M.R. (1980) Laboratory handbook of medical mycology. Academic Press, New York.
- McGinnis, M.R., Schell, W.A. and Carson, J. (1985) Phaeoannellomyces and the Phaeococcomycetaceae, new dematiaceous blastomycete taxa. Journal of Medical and Veterinary Mycology, 23, 179-188.
- Mok, W.Y. 1982. Nature and identification of Exophiala werneckii. Journal of Clinical Microbiology, 16, 976-978.
- Ng, K.P., Soo-Hoo, T.S., Na, S.L., et al. (2005) The mycological and molecular study of Hortaea werneckiiisolated from blood and splenic abscess. Mycopathologia, 159, 495–500.
- Rippon, J.W. (1988) Medical mycology: the pathogenic fungi and the pathogenic actinomycetes, 3rd edition. W,B. Saunders Co, Philadelphia, USA.