Stemphylium
Most species of Stemphylium are plant pathogens with occasional isolates from soil, they are rarely seen in the clinical laboratory.
RG-1 organism.
Conidiophore and conidia of Stemphylium spp.
Morphological description:
Colonies are rapid growing, brown to olivaceous-black or greyish and suede-like to floccose. Microscopically, solitary, darkly pigmented, terminal, multicellular conidia (dictyoconidia) are formed on a distinctive conidiophore with a darker terminal swelling. Note: The conidiophore proliferates percurrently through the scar where the terminal conidium (poroconidium) was formed. Conidia are pale to mid-brown, oblong, rounded at the ends, ellipsoidal, obclavate or subspherical and are smooth or in part verrucose. Stemphylium should not be confused with Ulocladium which produces similar dictyoconidia from a sympodial conidiophore, not from a percurrent conidiogenous cell as in Stemphylium.
Molecular identification:
ITS sequencing (Woudenberg et al. 2013).
Key features:
Dematiaceous hyphomycete producing darkly pigmented, dictyoconidia from the swollen end of a percurrent conidiophore.
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.
- Ellis, M.B. (1971) Dematiaceous hyphomycetes. Commonwealth Mycological Institute, Kew, Surrey, England.
- Ellis, M.B. (1976) More dematiaceous hyphomycetes. Commonwealth Mycological Institute, Kew, Surrey, England.
- Kidd, S., Halliday, C., Ellis, D. (2023) Descriptions of Medical Fungi (4th edition). CABI.
- Rippon, J.W. (1988) Medical mycology: the pathogenic fungi and the pathogenic actinomycetes, 3rd edition. W,B. Saunders Co, Philadelphia, USA.
- Woudenberg, J.H., Groenewald, J.Z., Binder, M., et al. (2013) Alternaria redefined. Studies in Mycology, 75, 171-212.