Exophiala phaeomuriformis | |
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![]() | |
Scientific classification
![]() | |
Domain: | Eukaryota |
Kingdom: | Fungi |
Division: | Ascomycota |
Class: | Eurotiomycetes |
Order: | Chaetothyriales |
Family: | Herpotrichiellaceae |
Genus: | Exophiala |
Species: | E. phaeomuriformis
|
Binomial name | |
Exophiala phaeomuriformis Matos (2003)
| |
Synonyms | |
|
Exophiala phaeomuriformis is thermophilic fungus belonging to the genus Exophiala and the family Herpotrichiellaceae. [1] [2] it is a member of the group of fungi known as black yeasts, and is typically found in hot and humid locations, such as saunas, bathrooms, and dishwashers. [3] This species can cause skin infections [4] and is typically classified as a Biosafety Risk Group 2 agent. [5]
Exophiala phaeomuriformis is a member of the genus Exophiala, described in 1952 based on E. jeanselmei. [1] Thirty species of Exophiala are currently recognized [6] amongst which Exophiala (Wangiella) dermatitidis is the most common. [7] When studying samples of E. dermatitidis, Tadahiko Matsumoto and colleagues observed strains with a granular colonial form and distinctive microscopic morphology. [8] Based on the resemblance of these strains to the genus Sarcinomyces, they proposed the new name, S. phaeomuriformis. [8] This taxon was transferred to the genus Exophiala by Tiago Matos and co-workers in 2003 because of its yeast-like morphology (rather than the meristematic form characteristic to members of the genus Sarcinomyces), and its closer DNA homology to the genus Exophiala. [9]
Exophiala phaeomuriformis is a dematiceous (darkly pigmented) fungus and member of the group of fungi known as the black yeasts. [10] [11] Black yeasts are an unrelated category of fungi that share yeast-like morphology and possess darkly melanized cell walls. [5] Although their DNA sequences are distinctive, E. phaeomuriformis and E. dermatitidis are so closely related that the two cannot be reliably differentiated morphologically or physiologically. [5] [12] Antigenic cross-reactivity suggests that E. phaeomuriformis may have originated as multicellular variant of E. dematitidis. [10]
Like many other black yeasts, Exophiala phaeomuriformis is known only by its asexual form and no sexual form has been found. [4] [5] [8] It is a thermophilic fungus preferring temperatures between 37–42 °C (99–108 °F) [2] but growing at any temperature between 15–42 °C (59–108 °F). [3] Exophilala phaeomuriformis is more sensitive than other black yeasts to salt, incapable of growth at concentrations of sodium chloride exceeding 17%. [3] Like other members of the genus Exophiala, it is able to tolerate a wide range of pH (2.5–12.5). [3]
Colonies of E. phaeomuriformis are hyaline, mycoid, and smooth when young [9] but become black, dry, crumbly, raised, and mulberry-like in texture with age. [4] [8] Some strains fail to undergo this morphological switch and remain yeast-like in age. [5] [8] By contrast, many strains of E. dermatitidis become mycelial with age. [8] Hyphal growth has not been observed in E. phaeomuriformis. [8] Instead, colonies develop from loosely packed, single, and rounded budding yeast cells that are either scattered or aggregated in groups. [5] [8] Vegetative cells can either by unicellular or muriform (septate in all planes) or become divided by transverse septa only. [4] [8] Yeast cells are thick-walled and spherical or near-spherical in shape. [4] [5] Budding cells can have broad bases, occur in chains, and be multilateral, budding in different directions. [9]
Like other member of the genus Exophiala, E. phaeomuriformis is saprotrophic, obtaining its energy exclusively from non-living organic materials. [6] When inoculated on a suitable growth medium under optimal conditions, the growth of E. phaeomuriformis is initiated in roughly 3 days; [3] however, when subject to competition, the cells may remain in a stationary state for many weeks prior to the development of visible growth. [3] Similar to E. dematitidis, E. phaeomuriformis is unable to assimilate nitrate, nitrite and melibiose; however it differs in it that some strains are unable to metabolize D-gluconate, D-glucuronate, D-galacturonate and glucono-δ-lactone. [10]
Exophiala phaeomuriformis has a proclivity for environments rich in mono- and polyaromatic compounds, such as hydrocarbons, where it uses these compounds as sources of energy. [3] The species is plurivorous, occurring on a wide range of materials from contaminated soils and toluene rich environments to wild berries and animal feces. [3] It is also found in environments containing the preservative creosote, such as railroad ties where it is an important agent of biodeterioration. [3] [13] In indoor environments, E. phaeomuriformis occurs in warm and moist environments such as toilets, saunas, or dishwashers. [2] This species is found world-wide. [14]
Exophiala phaeomuriformis is a rare causative agent of phaeohyphomycosis [15] in cutaneous, subcutaneous and deep tissues, [4] and is responsible for 6.4% of infections caused by black yeasts. [7] Infection usually occurs following skin abrasion or penetrating injuries. [11] Exophiala phaeomuriformis can also cause corneal infection following eye exposure to contaminated water. [1] People with cystic fibrosis (CF) are considered abnormally susceptible to Exophiala infections, including E. phaeomuriformis. [14] [16] It has been suggested that differences in the microbiota profiles of CF patients may be responsible for this predisposition. [17] Treatment of E. phaeomuriformis involves a combination of surgical debridement and antifungal therapy. [15] A range of antifungal agents including caspofungin, voriconazole, itraconazole, posaconazole, and amphotericin B are active against this species. [16] [18] Due to its pathogenic potential, E. phaeomuriformis is regarded as a Biosafety Risk Group 2 agent in the laboratory. [5]
{{
cite book}}
: CS1 maint: multiple names: authors list (
link)
Exophiala phaeomuriformis | |
---|---|
![]() | |
Scientific classification
![]() | |
Domain: | Eukaryota |
Kingdom: | Fungi |
Division: | Ascomycota |
Class: | Eurotiomycetes |
Order: | Chaetothyriales |
Family: | Herpotrichiellaceae |
Genus: | Exophiala |
Species: | E. phaeomuriformis
|
Binomial name | |
Exophiala phaeomuriformis Matos (2003)
| |
Synonyms | |
|
Exophiala phaeomuriformis is thermophilic fungus belonging to the genus Exophiala and the family Herpotrichiellaceae. [1] [2] it is a member of the group of fungi known as black yeasts, and is typically found in hot and humid locations, such as saunas, bathrooms, and dishwashers. [3] This species can cause skin infections [4] and is typically classified as a Biosafety Risk Group 2 agent. [5]
Exophiala phaeomuriformis is a member of the genus Exophiala, described in 1952 based on E. jeanselmei. [1] Thirty species of Exophiala are currently recognized [6] amongst which Exophiala (Wangiella) dermatitidis is the most common. [7] When studying samples of E. dermatitidis, Tadahiko Matsumoto and colleagues observed strains with a granular colonial form and distinctive microscopic morphology. [8] Based on the resemblance of these strains to the genus Sarcinomyces, they proposed the new name, S. phaeomuriformis. [8] This taxon was transferred to the genus Exophiala by Tiago Matos and co-workers in 2003 because of its yeast-like morphology (rather than the meristematic form characteristic to members of the genus Sarcinomyces), and its closer DNA homology to the genus Exophiala. [9]
Exophiala phaeomuriformis is a dematiceous (darkly pigmented) fungus and member of the group of fungi known as the black yeasts. [10] [11] Black yeasts are an unrelated category of fungi that share yeast-like morphology and possess darkly melanized cell walls. [5] Although their DNA sequences are distinctive, E. phaeomuriformis and E. dermatitidis are so closely related that the two cannot be reliably differentiated morphologically or physiologically. [5] [12] Antigenic cross-reactivity suggests that E. phaeomuriformis may have originated as multicellular variant of E. dematitidis. [10]
Like many other black yeasts, Exophiala phaeomuriformis is known only by its asexual form and no sexual form has been found. [4] [5] [8] It is a thermophilic fungus preferring temperatures between 37–42 °C (99–108 °F) [2] but growing at any temperature between 15–42 °C (59–108 °F). [3] Exophilala phaeomuriformis is more sensitive than other black yeasts to salt, incapable of growth at concentrations of sodium chloride exceeding 17%. [3] Like other members of the genus Exophiala, it is able to tolerate a wide range of pH (2.5–12.5). [3]
Colonies of E. phaeomuriformis are hyaline, mycoid, and smooth when young [9] but become black, dry, crumbly, raised, and mulberry-like in texture with age. [4] [8] Some strains fail to undergo this morphological switch and remain yeast-like in age. [5] [8] By contrast, many strains of E. dermatitidis become mycelial with age. [8] Hyphal growth has not been observed in E. phaeomuriformis. [8] Instead, colonies develop from loosely packed, single, and rounded budding yeast cells that are either scattered or aggregated in groups. [5] [8] Vegetative cells can either by unicellular or muriform (septate in all planes) or become divided by transverse septa only. [4] [8] Yeast cells are thick-walled and spherical or near-spherical in shape. [4] [5] Budding cells can have broad bases, occur in chains, and be multilateral, budding in different directions. [9]
Like other member of the genus Exophiala, E. phaeomuriformis is saprotrophic, obtaining its energy exclusively from non-living organic materials. [6] When inoculated on a suitable growth medium under optimal conditions, the growth of E. phaeomuriformis is initiated in roughly 3 days; [3] however, when subject to competition, the cells may remain in a stationary state for many weeks prior to the development of visible growth. [3] Similar to E. dematitidis, E. phaeomuriformis is unable to assimilate nitrate, nitrite and melibiose; however it differs in it that some strains are unable to metabolize D-gluconate, D-glucuronate, D-galacturonate and glucono-δ-lactone. [10]
Exophiala phaeomuriformis has a proclivity for environments rich in mono- and polyaromatic compounds, such as hydrocarbons, where it uses these compounds as sources of energy. [3] The species is plurivorous, occurring on a wide range of materials from contaminated soils and toluene rich environments to wild berries and animal feces. [3] It is also found in environments containing the preservative creosote, such as railroad ties where it is an important agent of biodeterioration. [3] [13] In indoor environments, E. phaeomuriformis occurs in warm and moist environments such as toilets, saunas, or dishwashers. [2] This species is found world-wide. [14]
Exophiala phaeomuriformis is a rare causative agent of phaeohyphomycosis [15] in cutaneous, subcutaneous and deep tissues, [4] and is responsible for 6.4% of infections caused by black yeasts. [7] Infection usually occurs following skin abrasion or penetrating injuries. [11] Exophiala phaeomuriformis can also cause corneal infection following eye exposure to contaminated water. [1] People with cystic fibrosis (CF) are considered abnormally susceptible to Exophiala infections, including E. phaeomuriformis. [14] [16] It has been suggested that differences in the microbiota profiles of CF patients may be responsible for this predisposition. [17] Treatment of E. phaeomuriformis involves a combination of surgical debridement and antifungal therapy. [15] A range of antifungal agents including caspofungin, voriconazole, itraconazole, posaconazole, and amphotericin B are active against this species. [16] [18] Due to its pathogenic potential, E. phaeomuriformis is regarded as a Biosafety Risk Group 2 agent in the laboratory. [5]
{{
cite book}}
: CS1 maint: multiple names: authors list (
link)