Mycology case of the week(#8):
An adult patient with discoloration, thickening, and
crumbling at the edge of his fingernails. samples of the subungual debris grew
below fungus. Differential diagnosis?
Photos: courtesy of NRL-Dr. Mubarak.
Mycology case of the week (#15): An adult immunocompromised patient with Chronic cough. Sample from BAL grew below fungus. How many mold types in this photo?
Mycology case of the week(#8)- case discussion:
ReplyDeleteCurvularia spp.
TAXONOMY NOTES: The genus Curvularia has undergone extensive taxonomic revision. Human pathogenic Bipolaris spp. have been moved to the genus Curvularia. This includes the former species B. australiensis, B. hawaiiensis, and B. spicifera. Other medically important species in the genus Curvularia include C. geniculata and C. lunata. There are many other species of Curvularia that may be capable of causing infections in immunocompromised hosts.
PATHOGENICITY: Etiologic agents of opportunistic infections, most commonly causing keratitis and allergic/chronic sinusitis. May also cause onychomycosis as well as dark grain mycetoma and phaeohyphomycosis at various sites, including subcutaneous tissue and deep tissues. Keratitis, sinusitis, cutaneous and subcutaneous infections, peritonitis, onychomycosis, endocarditis, endophthalmitis, and pneumonia as well as disseminated disease have also been reported. Dissemination to the brain is known to occur occasionally in immunocompetent and immunocompromised individuals, often following sinusitis or lung infection. There is also an apparent association between heavy marijuana use and Curvularia infection, presumably from inhalation of the organism on contaminated marijuana leaves.
RATE OF GROWTH: Rapid; mature within 5 days.
COLONY MORPHOLOGY: Surface of Curvularia spp. (C. geniculata, C. lunata, and other species) is dark olive‐green to brown or black with a pinkish gray, woolly surface. Reverse is dark.
Surface of former Bipolaris spp. (B. australiensis, B. hawaiiensis, and B. spicifera) that are now recognized as Curvularia is at first grayish brown, becoming black with a matted center and raised grayish periphery. Reverse is dark brown to black.
MICROSCOPIC MORPHOLOGY: Curvularia spp. (C. geniculata, C. lunata, and other species) have dark, septate hyphae. Conidiophores are simple or branched and bent or knobby at points of conidium formation (sympodial geniculate growth). Conidia are large (8–14 × 21–35 μm), usually contain four cells and eventually appear curved due to swelling of a central cell (the curving may take 5 or more days to develop).
The former Bipolaris spp. (B. australiensis, B. hawaiiensis, and B. spicifera) that are now recognized as Curvularia have dark, septate hyphae. Conidiophores elongate and bend at the point where each conidium is formed (sympodial geniculate growth); this produces a knobby, zigzag appearance. Conidia are hyaline when immature, brown when mature, oblong to cylindrical (6–13 × 14–39 μm), appear thick walled, rounded at both ends, have three to five transverse septations, and a slightly protruding hilum.