7.2- + HISTOPLASMOSIS+BLASTOMYCOSIS+PARACOCCIDIOIDOMYCOSIS Flashcards
(109 cards)
Chronic infection with granulomatous and suppurative lesions, initiated in the lungs
blastomycosis
What organs are commonly affected in disseminated blastomycosis?
Skin and bones
What are the other names for blastomycosis?
North American blastomycosis
Gilchrist’s disease
Chicago disease
What is the etiologic agent of blastomycosis?
Blastomyces dermatitidis
Ajellomyces dermatitidis
Why is blastomycosis more common in males?
Due to occupational and recreational exposure in soil (sometimes riverbanks)
What animal is relatively commonly infected with blastomycosis?
Dogs
Can blastomycosis be transmitted between animals or humans?
No
What is the natural habitat of Blastomyces dermatitidis?
Unknown, but linked to rural riverbanks in small outbreaks
What is the colonial appearance of Blastomyces dermatitidis in the mycelial phase?
On SDA: Initially white, waxy, yeast-like → later cottony with white aerial mycelium, turning tan to brown with age
What is the colonial appearance of Blastomyces dermatitidis in the yeast phase?
On BHI agar with blood: Cream to tan, waxy, heaped or wrinkled; inhibited by chloramphenicol or cycloheximide
What is the growth rate of Blastomyces dermatitidis?
7–28 days
What is the microscopic appearance of Blastomyces dermatitidis in the mycelial phase?
Delicate, septate hyphae with round or pyriform conidia borne singly on conidiophores or directly on hyphae (“lollipop” appearance)
What is the microscopic appearance of Blastomyces dermatitidis in the yeast phase?
Thick-walled, large yeast cells with single broad-based bud and broad isthmus at a constriction
What antigen is used in diagnostic testing for Blastomyces dermatitidis?
Blastomycin (mixture of antigens from culture filtrates)
What is antigen A in Blastomyces dermatitidis?
A specific antigen detected in ID tests for B. dermatitidis
A cell-surface and secreted protein with an immunodominant motif, responsible for generating a protective cell-mediated immune response
BAD-1 in blastomycosis
What is the most common clinical presentation of blastomycosis?
Pulmonary infiltrate with various symptoms; chronic pneumonia may also be present
What histologic reaction is seen in blastomycosis?
Pyogranulomatous reaction with neutrophils and noncaseating granulomas
What is the most common site of skin lesions in disseminated blastomycosis?
Exposed surfaces
What are the characteristics of blastomycosis skin lesions?
Ulcerated verrucous granulomas with an advancing border and central scarring
What other organs can be affected in blastomycosis?
Bone, genitalia, and CNS
Is blastomycosis common in AIDS patients?
No
What specimens are used for blastomycosis diagnosis?
Sputum, pus, exudates, urine, and lesion biopsies
What might wet mounts of blastomycosis specimens show?
Broadly attached buds on thick-walled yeast cells