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21 Cards in this Set
- Front
- Back
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What is the thermal dimorphic conversion for yeast and mold?
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37 deg.= yeast
25 deg.= mold *soil fungus that is inhaled and has potential to disseminate |
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What are the systemic pathogens?
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Coccidiodies immitis
Histoplasma capsulatum Blastomyces dermatitidis Paracoccidioids brasiliensis |
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What is Coccidioides immitis known as?
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valley fever, san juaquin valley fever
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What is the morphology of Coccidioides immitis?
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Dimorphic
Spherule w/ endospores (test Q) Arthrocondidium (test Q) White gray, or brown colony Powdery or wooly colony Hyphae fragment easily and release arthrocondidia |
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What are Coccidioides immitis Antigenic factors?
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Coccidioidin and Spherulin (produced in broth in which the mycelium grows)
Coccidioidin-positive skin test in infected person *Both have value in immunodiagnosis |
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What is the pathogenicity of Coccidiodes immitis?
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-Upon inhalation, the arthroconidia are transformed into pulmonary spherules (contain endospores)
-Endospores are released from spherules; endospores produce new spherules -Septate hyphae and arthroconidia are sometimes associated w/ the spherules in the pulmonary cavities. Pulmonary-primary involvement Influenza-like manifestations May develop into diffuse pneum Possibly asymptomatic Most infections are self-limited Disseminated disease More common in certain races Higher prevalence during preg Problem in immunodeficient -Erythema nodosum (good progn)-marked by tender red cutaneous nodule. - |
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What is the epidemiology of Coccidiodes immitis?
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Endemic to SW USA and areas of Latin America
- not communicable -Airborne transmission (inhalation of arthrocondidia) -Soil-dwelling -Infection rate is highest during the dry months when dust is more prevalent |
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What stain is specific for Fungi?
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PAS (+) result is specific for fungi
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What is the DOC for Coccidiodes immitis?
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Fluconazole, itraconazole, or amphotericin B.
Months of intravenous amphotericin B for disseminated and pulmonary coccidioidomycosis is required |
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What are some control methods for Coccidioides immitis?
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Dust protection
pave roads plant vegetation no vaccine |
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What is the morphology of Histoplasma capsulatum?
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Microconidium
Macroconidium Tuberculate (finger-like) macroconid Facultative intracellular parasites Culture: yeast (37) and mold (25) White to brown cottony colony Slow growing (up to 12 wk) |
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Pathogenicity of Histoplasma Capsulatum
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-Inhaled microconidia
-convert to a yeast cells -Cells may be phagocytosed and disseminated -Influenza like illness -Described as a reticuloendothelial disease |
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Histoplasma capsulatum
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Yeast with a macrophage
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Virulence factors for Histoplasma capsulatum
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-Yeast releases urease to raise pH
-Interferes w/ phagolysosome killing activity of phagolysosome |
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What is the Host resistance of Histoplasma Capsulatum?
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Intracellular parasite (macrophage)
Functional cell-mediated immunity is essential |
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Epidemiology of Histoplasma capsulatum
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Ohio and MIssissippi River valleys
Not communicable Soil microbe enriched w/ droppings Found in bat's intestine |
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Identification of Histoplasma capslatum
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Microscopic- intracellular yeast
Isolation- site of infection Serologic- latex agglutination |
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What is the DOC for Histoplasma capslatum?
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Itraconazole or amphotericin B
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What are some control for Histoplasma capsulatum?
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Dust protection
Formaldehyde soil spraying |
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Morphology of Blastomyces dermatitidis
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Dimorphic (broad-based yeast)
Pneumonia, cutaneous, disseminated Ohio and Mississippi Soil dwelling Infective stage-microconidium Microscope- yeast Therapy- Amphotericin B, Itraconazole or fluconazole |
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Pathogenicity of Blastomyces dermatitidis
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-Infection occurs as a result of inhaling the microconidia soil
-Pulmonary Granulomas -Extrapulmonary disease: CUTANEOUS GRANULOMAS |
