Help! Please Register

  The Fungi

  Introduction
  Descriptions
  Synonyms
  Image Bank
  Lecture Bank
  Video Bank


  Mycoses

  Introduction
  Human
  Veterinary
  Environmental
   Industrial
  Agricultural
  MSG


  Drugs

  Introduction
  Medical
  Veterinary
  Environmental
   Industrial
  Agricultural


  Laboratory

  Introduction
  Susceptibility
  MIC Database
  Procedures
  Histopathology


  Education &
  Tools

  Introduction
  Abbreviations
  Links
  CME
  Conference
   Highlights
  Bibliography
  Glossary
  Good Books
  Events Calendar


  About Us

  Introduction
  Our Mission
  Editorial Board
  Editorial Staff
  Supporters
  Contributors
  Legal Stuff
  Privacy Policy
  Kudos


  The Fungi

  Introduction
  Descriptions
  Synonyms
  Image Bank
  Lecture Bank
  Video Bank



This page updated:
1/27/2007 9:23:00 AM


DoctorFungus - All Rights Reserved © 2007 Copyright
& Privacy Policy


Site built and designed for doctorfungus by Webillustrated



You are here: The Fungi > Descriptions >


Alternaria spp.
(described by Nees ex Wallroth in 1816)

Say Me

Taxonomic Classification

Kingdom: Fungi
Phylum: Ascomycota
Class: Euascomycetes
Order: Pleosporales
Family: Pleosporaceae
Genus: Alternaria

Description and Natural Habitats

Alternaria is a cosmopolitan dematiaceous (phaeoid) fungus commonly isolated from plants, soil, food, and indoor air environment. The production of melanin-like pigment is one of its major characteristics. Its teleomorphic genera are called Clathrospora and Leptosphaeria.

Species

The genus Alternaria currently contains around 50 species. Among these, Alternaria alternata is the most common one isolated from human infections. Some authorities suggest that Alternaria alternata is a representative species complex rather than a single species and consists of several heterogenous species. While Alternaria chartarum, Alternaria dianthicola, Alternaria geophilia, Alternaria infectoria, Alternaria stemphyloides, and Alternaria teunissima are among the other Alternaria spp. isolated from infections, some Alternaria strains reported as causative agents remain unspecified.

Synonyms

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

Pathogenicity and Clinical Significance

Alternaria spp. have emerged as opportunistic pathogens particularly in patients with immunosuppression, such as the bone marrow transplant patients [1581] [2297]. They are one of the causative agents of phaeohyphomycosis. Cases of onychomycosis, sinusitis, ulcerated cutaneous infections, and keratitis, as well as visceral infections and osteomyelitis due to Alternaria have been reported [66, 802, 1429, 2042]. In immunocompetent patients, Alternaria colonizes the paranasal sinuses, leading to chronic hypertrophic sinusitis. In immunocompromised patients the colonization may end up with development of invasive disease[2306]. It is among the causative agents of otitis media in agricultural field workers [2345].

Since Alternaria species are cosmopolitan and ubiquitous in nature, they are also common laboratory contaminants. Thus, their isolation in culture requires cautious evaluation [1847].

Macroscopic Features

Alternaria spp. grow rapidly and the colony size reaches a diameter of 3 to 9 cm following incubation at 25°C for 7 days on potato glucose agar. The colony is flat, downy to woolly and is covered by grayish, short, aerial hyphae in time. The surface is greyish white at the beginning which later darkens and becomes greenish black or olive brown with a light border. The reverse side is typically brown to black due to pigment production [462, 1295, 2144].

Microscopic Features

Alternaria spp. have septate, brown hyphae. Conidiophores are also septate and brown in color, occasionally producing a zigzag appearance. They bear simple or branched large conidia (7-10 x 23-34 µm) which have both transverse and longitudinal septations. These conidia may be observed singly or in acropetal chains and may produce germ tubes. They are ovoid to obclavate, darkly pigmented, muriform, smooth or roughened. The end of the conidium nearest the conidiophore is round while it tapers towards the apex. This gives the typical beak or club-like appearance of the conidia [462, 1295, 2144].

Histopathologic Features

Dark colored filamentous hyphae are observed in the sections of infected tissue stained with H&E. If the pigment formation is not obvious, Fontana-Masson silver stain, which is specific to melanin, may be applied [462].

Compare to

Ulocladium, Stemphylium, Pithomyces, Dissitimurus, synanamorphic forms of Phoma.

Key features for differentiation from Ulocladium and Pithomyces [1295, 2144]


STRUCTURE
DIFFERENTIATION
Beak-like appearance at the apex of conidium
Alternaria (+)
Ulocladium (-)
Strongly geniculate conidiophore
Alternaria (-)
Ulocladium (+)
Conidia forming chains
Alternaria (+)
Ulocladium* (-)
Pithomyces** (-)

*conidia are usually single or form only very short chains
**never produces conidia in chains

Laboratory Precautions

No special precautions other than general laboratory precautions are required.

Susceptibility

In vitro susceptibility testing for phaeoid fungi is not standardized yet. The in vitro activity of some novel antifungal drugs has so far been investigated. While caspofungin was shown to be active in vitro against Alternaria [558], voriconazole also appeared promising and generated lower MICs than itraconazole for Alternaria strains [1864, 2432].

Amphotericin B and flucytosine therapy may achieve successful clinical outcome in phaehyphomycosis. Treatment with fluconazole, itraconazole, or terbinafine may also be effective [590]. However, further data are required to clarify their actual place in treatment of Alternaria infections.

For MICs of various antifungal agents so far reported for Alternaria, see our susceptibility database.

Search

PubMed

Nucleotides

GenBank



Alternaria alternata
Alternaria alternata
Alternaria geophilia
Alternaria geophilia
Alternaria spp.
Alternaria spp.



References

66. Anaissie, E. J., G. P. Bodey, and M. G. Rinaldi. 1989. Emerging fungal pathogens. Eur. J. Clin. Microbiol. Infect. Dis. 8:323-330.

462. Collier, L., A. Balows, and M. Sussman. 1998. Topley & Wilson's Microbiology and Microbial Infections, 9th ed, vol. 4. Arnold, London, Sydney, Auckland, New York.

558. Del Poeta, M., W. A. Schell, and J. R. Perfect. 1997. In vitro antifungal activity of pneumocandin L-743,872 against a variety of clinically important molds. Antimicrob. Agents Chemother. 41:1835-1836.

590. Diaz, M., R. Puente, and M. A. Treviņo. 1990. Response of long-running Alternaria alternata infection to fluconazole. Lancet. 336:513.

802. Garau, J., R. D. Diamond, L. B. Lagrotteria, and S. A. Kabins. 1977. Alternaria osteomyelitis [letter]. Ann. Intern. Med. 86:747-8.

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

1429. Manning, S. C., S. D. Schaefer, L. G. Close, and F. Vuitch. 1991. Culture-positive allergic fungal sinusitis. Archives of Otolaryngology -- Head & Neck Surgery. 117:174-8.

1581. Morrison, V. A., R. J. Haake, and D. J. Weisdorf. 1993. The spectrum of non-Candida fungal infections following bone marrow transplantation. Medicine (Baltimore). 72:78-89.

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.

1864. Radford, S. A., E. M. Johnson, and D. W. Warnock. 1997. In vitro studies of activity of voriconazole (UK-104,496), a new triazole antifungal agent, against emerging and less-common mold pathogens. Antimicrob. Agents Chemother. 41:841-843.

2042. Schell, W. A. 2000. Unusual fungal pathogens in fungal rhinosinusitis. Otolaryngol Clin N Amer. 33:367-373,X.

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

2297. Vartivarian, S. E., E. J. Anaissie, and G. P. Bodey. 1993. Emerging fungal pathogens in immunocompromised patients: classification, diagnosis, and management. Clin. Infect. Dis. 17:S487-91.

2306. Vennewald, I., M. Henker, E. Klemm, and C. Seebacher. 1999. Fungal colonization of the paranasal sinuses. Mycoses. 42:33-36.

2345. Wadhwani, K., and A. K. Srivastava. 1984. Fungi from otitis media of agricultural field workers. Mycopathologia. 88:155-9.

2432. Wildfeuer, A., H. P. Seidl, I. Paule, and A. Haberreiter. 1998. In vitro evaluation of voriconazole against clinical isolates of yeasts, moulds and dermatophytes in comparison with itraconazole, ketoconazole, amphotericin B and griseofulvin. Mycoses. 41:309-319.



  Home | Image Bank | Lecture Bank | Knowledgebase | Site Map | Contact Us |
The Fungi | Mycoses | Drugs |
Laboratory | Education & Tools | About Us

  bttm_banner_indv2_02[1].gif