Question | Answer |
Subcutaneous mycoses 4 major infections | Mycetoma, Chromoblastomycosis, Phaeohyphomycosis, Sporotrichosis |
Common to all subcutaneous mycoses | Lesion develops at site of inoculation (localized); soil saprophytes that are moderately slow growers; most are dematiaceous fungi |
Types of conidiation seen in dematiaceous fungi | Cladosporium type, Phialophora type, Rhinocladiella type |
Cladosporium type conidiation | Resembles a tree, conidiophore is trunk and branched chains of conidia form branches |
Phialophora type conidiation | Short conidiophores + phialide, vase shaped, conidia extrude from phialide and then cluster |
Rhinocladiella type conidiation | Stalked conidiophores that become knobby as conidia are produced, conidia produced sequentially until a cladosporium type conidiation is reached |
Media used for identification of subcutaneous fungi | SAB with and without antibiotics; PDA for subculture |
Mycetoma | Chronic granulomatous disease of feet; enlarges nodules, sinus drainage, bone destruction; granules in exudate; no lymphatic system involvement |
Two types of granules in mycetoma | Actinomycotic(narrow hyphae) and Eumycotic(wide hyphae, ending in chlamydoconidia) |
Chromoblastomycosis | Localized disease of skin and subcutaneous tissue; wart-like (verrucoid) lesions on feet, legs, hands, buttocks; soil saphrophytes introduced by trauma; dematiacious |
Chromoblastomycosis - what is seen microscopically | Single celled or clusters of single cells, dark pigment |
Chromoblastomycosis - setting up for culture | SAB at room temp, hold for 6 weeks |
What are you looking for in chromoblastomycosis | 3 types of conidiation: cladosporium type, rhionocladiella type, phialophora type |
Phaeohyphomycosis | Infection of subcutaneous tissue, caused by misc. dematiaceous fungi, introduced through trauma |
Phaeohyphomycosis - KOH shows | Pigmented hyphae |
Cause of chromoblastomycosis | Cladophialophora carrioinii |
Cladophialophora carrioinii macro | Slow grower - up to 30 days; grey-green to black surface and reverse, cottony |
Cladophialophora carrioinii micro | Pigmented, septate hyphae; cladosporium type conidiation |
Causes chromoblastomycosis and phaeohyphomycosis | Fonsecaea pedrosoi and Phialophora verrucosa |
Fonsecaea pedrosoi macro | Grey-green to black, cottony; slow grower, w/in 21 days |
Fonsecaea pedrosoi micro | Pigmented, spetate hyphae; all 3 types of conidiation: phialophora, cladosporium, rhinocladiella |
Phialophora verrucosa macro | Olive-green to black, velvety |
Phialophora verrucosa micro | Pigmented, septate hyphae; only phialophora type conidiation |
Major etiologic agent of mycetoma in US and Europe | Pseudallescheria boydii |
Pseudallescheria boydii macro | Grows rapidly; white to brownish-grey, fluffy |
Pseudallescheria boydii micro | Hyaline, septate hyphae; single anelloconidia produced on an anellophore (conidiophore) |
How is Pseudallescheria boydii different from other subcutaneous mycoses | Grows rapidly, hyaline, has a sexual form |
Cause of Mycetoma and phaehyphomycosis by minor trauma and contaminated fomites | Exophiala jeanselmei |
Exophiala jeanselmei macro | Young cultures: appear as black yeast; Mature cultures: velvety colonies |
Exophiala jeanselmei micro | Stick-like conidiophores with clustered conidia |
Wangiella dermatitidis causes | phaeohyphomycosis |
Wangiella dermatitidis macro | Initially resembles black yeast; > 10days, olive-grey to black, velvety or glabrous; grows better at 40-42C |
Wangiella dermatitidis micro | Pigmented, septate hyphae; conidiophores are indistinguishable from vegetative hyphae except conidia are clustered at ends |
Acremonium spp cause | Etiologic agent of mycetomas, corneal infections, and nail infections |
Madurella grisea macro | Folded in center with radial grooves, dark grey to olive-brown, reverse dark |
Madurella grisea micro | Dark, thick hyphae; other structures may be absent |
Madurella mycetomatis macro | Slow growing, fluffy white, grows best at 37C, reverse dark |
Madurella mycetomatis micro | Dark, thick hyphae, other structures may be absent, some have tiny flask-shaped phialides |