Fungal Diseases

Glossary of Fungal Diseases

Aspergillosis

There are a wide range of human and animal diseases caused by several species of Aspergillus, particularly Aspergillus fumigatus. The most predominant form of Aspergillosis is pulmonary and over 95% of all infections are caused by three species: (A. fumigatus, A. flavus, A. niger).

Chromoblastomycosis

A chronic, subcutaneous, granulomatous mycosis of man and higher animals caused by implantation in the skin of several dematiaceous (pigmented) fungi from exogenous sources (wood, soil, plant debris). The infection is usually distinguished by the unique finding of muriform “sclerotic bodies” in material from lesions. The traditionally recognized dematiaceous agents of chromoblastomycosis are: Fonsecaea pedrosoi (most common), Fonsecaea compacta, Cladophialophora carrionii, Phialophora verrucosa, andRhinocladiella aquaspersa. Recent reports have implicated infections withExophiala jeanselmei and Exophiala spinifera.

Endophthalmitis

An infection of the intraocular tissues of the eye and is usually associated with injury to the eye by instruments, fluids, and foreign materials during ocular surgery (exogenous contamination). Endogenous contamination of the eye may be the result of hematologic seeding but can also result from direct extension of an infectious process such as keratitis with intraocular extension.

Hyalohyphomycoses

Hyalohyphomycoses is caused by a group of heterogeneous fungi with only hyaline hyphae (without pigment in the wall) that may include only localized infection (usually following traumatic implantation) whereas disseminated disease tends to occur among immunosuppressed persons. A number of fungi causing this disease are increasing and the most common ones includeFusarium spp., Penicillium spp., Scedosporium spp., Acremonium spp., andPaecilomyces spp.

Keratitis

An inflammation of the cornea. Mycotic keratitis may be a potentially serious fungal infection of the cornea and based on numerous reports fungi have been found to cause 6%-53% of cases of ulcerative keratitis. More than 70 species of fungi have been reported to cause mycotic keratitis.

Mycetoma

A chronic subcutaneous infection caused by actinomycetes or fungi. It is characterized by the formation of abscesses, which contain aggregates of fungal or actinomycete filaments known as grains. Mycetoma has numerous causes, with more than 20 species of fungi (eumycotic) or actinomycetes (bacteria) being commonly involved. The main agents of actinomycotic mycetoma include Streptomyces, Actinomadura, and Nocardia brasiliensis(the most common actinomycete). The fungi include Madurella mycetomatis(the most common fungus), Madurella grisea, Leptosphaeria senegalensis, Pseudallescheria boydii, and species of Fusarium, Acremonium, andAspergillus.OnychomycosisInfection of the nails seen mainly in adults. The toenails are more commonly infected than the fingernails. The most common cause is the dermatophyte, Trichophyton rubrum. Other nondermatophyte fungi may cause onychomycosis such as Candida spp., Scopulariopsis brevicaulis, Scytalidium, Aspergillus, Pyrenochaeta, and Chaetomium species.

Otomycosis

Infections of the external auditory canal caused by Candida species, Aspergillus, particularly Aspergillus niger, and a variety of other fungi. An aggressive form of external otitis noted in immunocompromised patients, malignant otitis externa, which may be caused by fungi, particularlyAspergillus species.

Phaeohyphomycosis

Includes infections caused by all agents appearing in tissue as dematiaceous (pigmented) yeast cells, pseudohyphae-like elements, septate hyphae, or any combination of these forms (McGinnis & colleagues). The number of fungi implicated as etiologic agents includes at least 104 different species from 57 genera. Phaeohyphomycosis has been divided into four disease categories (Fader and McGinnis): superficial, cutaneous and corneal, subcutaneous, and systemic.

Zygomycosis

Comprises various types of infections caused by zygomycetes. Members of the order Mucorales (Mucormycosis) has often been implicated in causing this disease. There are several distinct forms of the disease which include rhinocerebral, pulmonary, cutaneous, and disseminated mycosis. The most often implicated mould in zygomycosis is Rhizopus species.Other zygomycetes such as Mucor, Apophysomyces, Saksenaea, Cokeromyces, Basidiobolus, and Conidiobolus species have also been reported to cause disease.

References for Identification of Fungi:


Guide to Clinically Significant Fungi: Sutton DA, Fothergill AW, Rinaldi MG, 1998.Identifying Filamentous Fungi: “A Clinical Laboratory Handbook”, St-Germain G, Summerbell R, 1996.

Pictorial Atlas of Soil & Seed Fungi: 2nd Edition, Watanabe T, 2002.

Introduction to Food and Airborne Fungi: 6th Edition, Samson RA, Hoekstra ES, Frisvad JC, Filtenborg O, 2000.

Medically Important Fungi: “A Guide to Identification”, 4th Edition, Larone DH, ASM Press 2002.

Atlas of Clinical Fungi: 2nd Edition, de Hoog GS, Guarro JG, Figueras, MJ, 2000.

The Genera of Hyphomycetes from Soil: Barron,1972.

Identification Manual for Fungi from Utility Poles in the Eastern US: Wang CJK, Zabel RA, 1990.

Laboratory Handbook of Dermatophytes: Kane J, Summerbell R, Sigler L, Krajden S, Land G, 1997.

Manual of Clinical Microbiology: 9th Edition. Patrick Murray, Ellen Jo Baron, James Jorgensen, Marie L. Landry, Michael A. Pfaller, ASM Press, Washington, DC, 2007.

Anaisse, EJ, McGinnis MR, Pfaller MA: Clinical Mycology, 2003.

Manual of Environmental Microbiology: 3rd Edition, Hurst CJ, Crawford RL, Garland, JL., Lipson, DA., Mills, AL., and Stetzenbach LD, ASM Press, Washington, DC, 2007.

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