Pleurostoma
Synonymy:
Phialophora richardsiae; Pleurostomophora richardsiae.
Pleurostoma richardsiae was separated from Phialophora based on molecular data (Vijaykrishna et al., 2004; Reblova et al., 2015). Pleurostoma richardsiae is a soft rot fungus of wood and is an uncommon cause of human infection, usually through traumatic implantation causing subcutaneous phaeohyphomycosis.
Phialides of Pleutostoma richardsiae producing 2 types of conidia. (1) hyaline conidia, formed on inconspicuous, peg-like phialides on thin-walled hyphae; and (2) brown, thick-walled conidia formed on dark brown, slender, tapering phialides with flaring collarettes.
RG-2 organism.
Morphological description:
Colonies grow rapidly, and are powdery to woolly or tufted, greyish-brown with a grey-brown to olivaceous-black reverse. Two conidial types are produced: (1) hyaline conidia which are allantoid or cylindrical, 3-6 x 1.5-2.5 μm in size, formed on inconspicuous, peg-like phialides on thin-walled hyphae; and (2) brown, thick-walled conidia which are spherical to subspherical, 2.5-3.5 x 2-3 μm, formed on dark brown, slender, tapering phialides with flaring collarettes.
Key features:
P. richardsiae is characterised microscopically by phialides with prominent flaring collarettes bearing globose, brown conidia while phialides with indistinct collarettes bear pale allantoid to cylindrical conidia.
Molecular identification:
ITS sequencing is recommended (Vijaykrishna et al. 2004).
| Antifungal susceptibility: Pleurostoma richardsiae (Australian national data); MIC µg/mL | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| No | ≤0.016 | 0.03 | 0.06 | 0.125 | 0.25 | 0.5 | 1 | 2 | 4 | 8 | ≥16 | |
| AmB | 17 | 1 | 2 | 5 | 7 | 2 | ||||||
| ISAV | 2 | 1 | 1 | |||||||||
| VORI | 17 | 4 | 8 | 5 | ||||||||
| POSA | 15 | 1 | 3 | 3 | 6 | 2 | ||||||
| ITRA | 17 | 2 | 6 | 6 | 3 | |||||||
References:
- 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.
- Domsch, K.H., Gams, W. and Anderson, T.H. (2007) Compendium of soil fungi. Second Edition, IHW-Verlag, Germany.
- Ellis, M.B. (1971) Dematiaceous hyphomycetes. Commonwealth Mycological Institute, Kew, Surrey, England.
- Kidd, S., Halliday, C., Ellis, D. (2023) Descriptions of Medical Fungi (4th edition). CABI.
- McGinnis, M.R. (1978) Human pathogenic species of Exophiala, Phialophora, and Wangiella. In the black and white yeasts. Proceedings of the fourth international conference on the mycoses. Scientific Publication No. 356. Pan American Health Organization. Washington, DC, USA. pp.37-59.
- McGinnis, M.R. (1980) Laboratory handbook of medical mycology. Academic Press, New York.
- Reblova, M., Jaklitsch, W.M., Reblova, K., et al. (2015) Phylogenetic reconstruction of the Calosphaeriales and Togniniales using five genes and predicted RNA secondary structures of ITS, and Flabellascus tenuirostrisgen. et sp. nov, PloS One, 10, e0144616-e0144616.
- Revankar, S.G. and Sutton, D.A. (2010) Melanized fungi in human disease. Clinical Microbiology Reviews, 23, 884-928.
- Vijaykrishna, D., Mostert, L., Jeewon, R., et al. (2004) Pleurostomophora, an anamorph of Pleurostoma(Calosphaeriales), a new anamorph genus morphologically similar to Phialophora. Studies in Mycology, 50, 387-395.