Nigrospora Species

Kingdom: Fungi
Phylum: Ascomycota
Order: Trichosphaeriales
Family: Trichosphaeriaceae
Genus: Khuskia (teleomorph)

Nigrospora is a filamentous dematiaceous fungus widely distributed in soil, decaying plants, and seeds. It is a common laboratory contaminant. Although it has been isolated from a few clinical samples, its pathogenicity in man remains uncertain [531, 1295, 2144, 2202].

Nigrospora sphaerica is the best-known species of the genus Nigrospora.

See the summary of synonyms and teleomorph-anamorph relations for Nigrospora spp.

Nigrospora has been isolated from cutaneous lesions of a leukemic patient and from a case with keratitis. However, its pathogenic role as a causative agent is not well-known [1847, 2218].

Nigrospora grows rapidly and produces woolly colonies on potato dextrose agar at 25°C. The colonies mature within 4 days. Color of the colony is white initially and then becomes gray with black areas and turns to black eventually from both front and reverse. Sporulation may take more than 3 weeks for some isolates [531, 1295, 2144, 2202].

Septate hyaline hyphae, hyaline or slightly pigmented conidiophores, and conidia are visualized. The conidiogenous cells on the conidiophores are inflated, swollen, and ampulliform in shape. They bear a single conidium (14-20 µm in diameter) at their apex. Conidia are black, solitary, unicellular, slightly flattened horizontally, and have a thin equatorial germ slit [531, 1295, 2144, 2202].

Humicola

Nigrospora is differentiated from Humicola by its very black conidia that originate from hyaline, inflated conidiophores.

No special precautions other than general laboratory precautions are required.

No data are available.

PubMed

GenBank

Nigrospora spp. produce conidiophores which forcibly discharge the conidia

References

531. de Hoog, G. S., J. Guarro, J. Gene, and M. J. Figueras. 2000. Atlas of Clinical Fungi, 2nd ed, vol. 1. Centraalbureau voor Schimmelcultures, Utrecht, The Netherlands.

1295. Larone, D. H. 1995. Medically Important Fungi - A Guide to Identification, 3rd ed. ASM Press, Washington, D.C.

1847. Pritchard, R. C., and D. B. Muir. 1987. Black fungi: a survey of dematiaceous hyphomycetes from clinical specimens identified over a five year period in a reference laboratory. Pathology. 19:281-4.

2144. St-Germain, G., and R. Summerbell. 1996. Identifying Filamentous Fungi - A Clinical Laboratory Handbook, 1st ed. Star Publishing Company, Belmont, California.

2202. Sutton, D. A., A. W. Fothergill, and M. G. Rinaldi (ed.). 1998. Guide to Clinically Significant Fungi, 1st ed. Williams & Wilkins, Baltimore.

2218. Talwar, P., and S. C. Sehgal. 1978. Mycotic infections of the eye in Chandigarh and neigbouring areas. Ind J Med Res. 67:929-933.