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''Exophiala dermatitidis'' is a thermophilic black yeast, and a member of the Herpotrichiellaceae.〔〔 While the species is only found at low abundance in nature, metabolically active strains are commonly isolated in saunas, steam baths, and dish washers.〔〔 ''Exophiala dermatitidis'' only rarely causes infection in humans, however cases have been reported around the world. In East Asia, the species has caused lethal brain infections in young and otherwise healthy individuals.〔 The fungus has been known to cause cutaneous and subcutaneous phaeohyphomycosis,〔〔 and as a lung colonist in people with cystic fibrosis in Europe.〔 In 2002, an outbreak of systemic ''E. dermatitidis'' infection occurred in women who had received contaminated steroid injections at North Carolina hospitals.〔〔 == Appearance and general description == ''Exophiala dermatitidis'' forms slow growing, brown or black colonies.〔〔 As is common amongst black yeasts, ''E. dermatitidis'' is an anamorphic fungus with multiple conidial forms.〔〔〔 This morphological plasticity has complicated taxonomic determination based solely on physical appearance.〔 Young colonies are described as waxy,〔 mucoid,〔 smooth,〔〔 and yeastlike.〔〔 Over time pigmented aerial hyphae develop, and older colonies are described as appearing filamentous and velvety.〔〔〔〔 Conidia are between globular and elliptical in shape, and form at the mouth of short annellidic conidiogenous cells. Annellations can only be observed by electron microscopy.〔〔〔 Prior to analysis by SEM, the condiogenous cells were observed to form from non-annelated phialides and phialides without collarettes.〔 These observations caused the species to be erroneously provided with its own monotypic genus, ''Wangiella''.〔 The species name ''Wangiella dermatitidis'' is still commonly used in the scientific literature. The black fungus also takes on diverse morphologies ''in vivo''. Infected tissues contain mixtures of ovoid yeast-like cells, short septate hyphae that may be branched or unbranched, toruloid hyphae, as well as isotopically enlarged sclerotic (muriform-like) cells that resemble those found in chromoblastomycosis.〔〔 The muriform-like cells isolated from ''E. dermatitidis'' infections have thinner walls than those found in chromoblastomycosis, and cells are divided along a single plane.〔 A sexual form of ''E. dermatitidis'' has not been observed.〔 Sequencing of rDNA has shown that clinical isolates of ''E. dermatitidis'' are very closely related to ''Capronia mansonii,'' and It has been predicted that the ascospores and ascomata of an ''E. dermatitidis'' teleomorph would therefore resemble those of ''C. mansonii''.〔 Ideal growth conditions for ''E. dermatitidis'' occur between and ,〔〔〔 however ''E. dermatitidis'' can tolerate temperatures as high as .〔 Metabolically active fungus is highly abundant in Turkish steam baths that routinely reach temperatures of over , but is typically not found in more hot and dry sauna facilities, or in cool environments surrounding steam baths.〔 It is thought that extracellular polysaccharides may protect the species from stress in hot and moist environments, as this feature is typical of strains isolated from steam baths.〔〔 ''Exophiala dermatitidis'' has carotenoid pigments in its cell wall that may serve a role in protecting ''E. dermatitidis'' from UV damage.〔 Thermophilicity, negative potassium nitrate assimilation, negative melezitose assimilation, and an ability to decompose tyrosine are used to distinguish ''E. dermatitidis'' from other black yeasts.〔〔〔〔 An exoantigen test is useful in species determination, and DNA analysis can also be performed.〔 The fungus has been selectively isolated using high temperature incubation (at 40 °C) on media containing cycloheximide.〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Exophiala dermatitidis」の詳細全文を読む スポンサード リンク
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