You are here: 
text zoom : S | M | L
Printer Friendly Version
Further Enquiries

School of Molecular & Biomedical Science
The University of Adelaide
AUSTRALIA 5005

Contact:
Dr David Ellis
Email


Alternaria sp.

Colonies are fast growing, black to olivaceous-black or greyish, and are suede-like to floccose. Microscopically, branched acropetal chains (blastocatenate) of multicelled conidia (dictyoconidia) are produced sympodially from simple, sometimes branched, short or elongate conidiophores. Conidia are obclavate, obpyriform, sometimes ovoid or ellipsoidal, often with a short conical or cylindrical beak, pale brown, smooth-walled or verrucose.

Temperature: optimum 25-28C; maximum 31-32C. Risk Group1 organism.

Alternaria alternata
Alternaria alternata showing branched acropetal chains and multicelled, obclavate to obpyriform conidia with short conical beaks.

Alternaria species soon lose their ability to sporulate in culture. Potato dextrose agar and cornmeal agar are the most suitable media to use, and incubation under near ultra-violet light is recommended to maintain sporulation.

MIC data is limited.  Antifungal susceptibility testing of individual strains is recommended.

Antifungal MIC ug/mL Antifungal
MIC ug/mL
Range
MIC90
Range
MIC90
Itraconazole
0.125-2
1
Amphotericin B
0.125->16
2
Voriconazole
0.5-2
1
Posaconazole
0.06-0.25
0.25

 

Clinical significance:

The genus contains 44 species of which most are plant parasites, but a few species are ubiquitous and are also frequently soil-borne. A. alternata is the commonest of these. Although usually seen as saprophytic contaminants, Alternaria species are recognized causative agents of mycotic keratitis and phaeohyphomycosis. Clinical manifestations include cutaneous infections, paranasal sinusitis, osteomyelitis and peritonitis in patients on continuous ambulatory peritoneal dialysis (CAPD).

Mycosis: Phaeohyphomycosis

Further reading:

Domsch, K.H., W. Gams, and T.H. Anderson. 1980. Compendium of soil fungi. Volume 1. Academic Press, London, UK.

Kwon-Chung, K.J. and J.E. Bennett. 1992. Medical Mycology. Lea & Febiger, Philadelphia and London.