Term
| What are the agents of systemic mycoses? |
|
Definition
Dimorphic Fungi -->
Blastomyces dermatitidis
Histoplasma capsulatum
Coccidioides immitis
Paracoccidioides brasiliensis |
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|
Term
| What is a dimorphic fungi? |
|
Definition
Mold form at 25-30°C (in natural environment)
Yeast form at 35-37°C (in host) |
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Term
| What is the infectious form of the systemic mycoses? |
|
Definition
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|
Term
| What is the clinical form of the systemic mycoses? |
|
Definition
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|
Term
| How are systemic mycoses contracted? |
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Definition
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Term
| In which group are systemic mycoses the most prevalent? |
|
Definition
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Term
What is blastomycosis caused by Blastomyces dermatitidis also known as? |
|
Definition
Gilchrist's disease
North American blastomycosis
Chicago disease |
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|
Term
What is the natural reservoir of Blastomyces dermatitidis?
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|
Definition
|
|
Term
| How would you culture Blastomyces dermatitidis? |
|
Definition
Use nonselective media such as Sabouraud dextrose agar or brain-heart infusion agar
Culture two sets at 25°C and 37°C |
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|
Term
| What is the sexual form of Blastomyces dermatitidis called? |
|
Definition
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|
Term
| What is the colonial apperance of Blastomyces dermatitidis at 25°C? |
|
Definition
| The center can have raised areas called spicules or prickles |
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|
Term
| What are the microscopic characteristics of Blastomyces dermatitidis at 25°C? |
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Definition
| Conidia are on short lateral branches and are ovoid to dumbbell shaped |
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|
Term
| What are the characteristics of Blastomyces dermatitidis at 37°C? |
|
Definition
| Broad based budding yeast that are sphericle and refratile |
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|
Term
| How do you confirm the identity of Blastomyces dermatitidis? |
|
Definition
| Conversion of mold form to yeast form or the exoantigen immunodiffusion test |
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Term
| What makes the exoantigens detected in the axoantigen immunodiffusion test? |
|
Definition
|
|
Term
| How do Blastomyces dermatitidis infections present in immunocompetent patients? |
|
Definition
Initially they are usually asymptomatic
Pulmonary disease may follow and it may spread to the skin and bone |
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|
Term
How do Blastomyces dermatitidis infections present in immunosuppressed patients?
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|
Definition
| May disseminate to multiple organ systems and rapidly fatal |
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Term
| What is histoplasmosis caused by Histoplasma capsulatum also called? |
|
Definition
Reticuloendothelial cytomycosis
Cave disease
Sperlunker's disease |
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|
Term
| What is the reservoir for Histoplasma capsulatum? |
|
Definition
| Soil contaminated with bat and bird feces |
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|
Term
| What specimens can be used for Histoplasma capsulatum? |
|
Definition
| Specimens from the respiratory tract, liver, spleen, bone marrow, blood and exudates from lesions |
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|
Term
| Which specimens are best for finding Histoplasma capsulatum in AIDS patients? |
|
Definition
|
|
Term
| How would you cultures Histoplasma capsulatum? |
|
Definition
Culture two sets on Sabroud dextrose, brain-heart infusion or inhibitory mold agar
One set at 25°C and the other at 37°C |
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|
Term
| How do you confirm the ID of Histoplasma capsulatum? |
|
Definition
| The conversion of mold form to yeast form though complete conversion is rarely seen |
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Term
| What tests can you perform to detect Histoplasma capsulatum? |
|
Definition
Exoantigen immunodiffusion test to look for H and M antigens
Immunodiffusion with complement fixation
Skin testing |
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|
Term
| What are the early and mature microscopic characteristics of the mycelial culture of Histoplasma capsulatum? |
|
Definition
Early: round to pyriform microconidia
Mature: large echinulate or tuberculate macroconidia |
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Term
| What cells do the microconidia of Histoplasma capsulatum invade? |
|
Definition
| They are pahagocytized by macrophages in the lungs |
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|
Term
| How does histoplasmosis present in patients with an intact immune system? |
|
Definition
Light exposure: imited and usually asymptomatic, organisms can remain viable for years
Heavy exposure: acute pulmonary disease |
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Term
| How does histoplasmosis present in immunocompromised patients? |
|
Definition
| Disseminated potentially fatal disease |
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|
Term
| How does Histoplasmosis capsulatum appear under direct dectection? |
|
Definition
Small yeasts
Oval to round budding cells
Often clustered within monocytes and macrophages |
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|
Term
| What is coccidioidomycosis caused by Coccidioides immitis also known as? |
|
Definition
California disease
Valley fever
Desert rheumatism
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Term
| Where ecologically can Coccidioides immitis be found? |
|
Definition
| the Lower Snoran Life Zone |
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|
Term
| Which mycotic agent is the most virulent to humans? |
|
Definition
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Term
| What are the characteristics of the arthroconidia of Coccidioides immitis? |
|
Definition
| Barrel shaped, convert to spherules in host |
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|
Term
| How would you culture Coccidioides immitis? |
|
Definition
Does not convert readily to spherules at 35°C
Culture one set at 25°C |
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|
Term
| What are the colonial characteristics of Coccidioides immitis? |
|
Definition
Initially white to gray, moist, glaborous
Develops mycelium and appears to "bloom"
Mature colonies are tan to brown to lavender |
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|
Term
| What are the microscopic characteristics of Coccidioides immitis? |
|
Definition
Aerial hyphae grow at right angles to the vegetative hyphae
Arthroconidia are seperated by disjunctor cells |
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|
Term
| What tests can be used to detect Coccidioides immitis? |
|
Definition
Latex agglutination with immunodiffusion
Complement fixation especially for prognostic studies |
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|
Term
| What are possible complications of a primary Coccidioides immitis infection? |
|
Definition
Pulmonary disease
Allergy
Toxic erythema
Erythema nodosum (desert bumps)
Erythema multiforme (valley fever)
Arthritis (desert rheumatism) |
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|
Term
| How are primary infections of Coccidioides immitis treated? |
|
Definition
| Usually resolve without therapy |
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|
Term
| What does the coccidioidin skin test detect? |
|
Definition
Infection with Coccidioides immitis confers strong immunity to reinfection
This is detected using the coccidioidin skin test |
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|
Term
| What are possible complications of a secondary infection of Coccidioides immitis? |
|
Definition
Lung nodules
Cavitary lesions
Progressive pulmoary disease
Dissemination
Meningial involvment is common |
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|
Term
| What is paracoccidioidomycosis caused by Paracoccidioides brasiliensis also known as? |
|
Definition
South American blastomycosis
Brazilian blastomycosis
Lutz-Splendore-Almeida disease
Paracoccidioidal granuloma |
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|
Term
| How would you culture Paracoccidioides brasiliensis? |
|
Definition
| Culture two sets, one at 25°C and one at 35°C |
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Term
| What tests can be used to detect Paracoccidioides brasiliensis? |
|
Definition
Complement fixation
Immunodiffusion |
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Term
| What are the characteristics of the yeast form of Paracoccidioides brasiliensis? |
|
Definition
| Multipolar budding on the periphery resembling a "mariner's wheel" |
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Term
| What is the usual route of infection for Paracoccidioides brasiliensis? |
|
Definition
|
|
Term
| What are possible complications of infection with Paracoccidioides brasiliensis? |
|
Definition
Often asymptomatic
Ulcerative granulomatous lesions
Disemination - predilection for adrenal glands |
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|
Term
| What phylum causes opportunistic infections? |
|
Definition
|
|
Term
| What does the Zygomyces show a strong predilection for invading? |
|
Definition
|
|
Term
| What is the most common disease caused by Zygomyces? |
|
Definition
| Rhinocerebral zygomycosis |
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|
Term
| What is Rhinocerebral zygomycosis? |
|
Definition
Most common Zygomycoses
Effects diabetics the most
Originates in paranasal sinus and can extend to the brain |
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|
Term
| What are the characteristics of the Zygomycete Mucor? |
|
Definition
Rapid grower
Cottony dirty white colonies
No rhizoids |
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|
Term
| What are the characteristics of the Zygomycete Rhizopus? |
|
Definition
Rapid grower
Brown rhizoids
Clusters of sporangiophores are joined by stolons |
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|
Term
| What are the characteristics of Penicillium? |
|
Definition
Rapid grower
Green or blue-green colonies
Phialides with oval conidia in chains |
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|
Term
| What are the three species of Aspergillus? |
|
Definition
Aspergillus fumigatus
flavus
niger |
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|
Term
| What is the most commonly found genus of fungi in the clinical lab? |
|
Definition
|
|
Term
| What is the most common isolate of Aspergillus? |
|
Definition
|
|
Term
| What is the infectious form of Aspergillus? |
|
Definition
|
|
Term
| What are the hypersensitivity reactions to Aspergillus? |
|
Definition
Types 1 and 4
Allergic bronchopulmoary infection
Asthma
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|
|
Term
|
Definition
"Fungus ball"
Occurs in cavities from tuberculosis or cancers |
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|
Term
| What does Aspergillus cause in immunocompromised patients? |
|
Definition
| Invasive penumonia and dissemination |
|
|
Term
| What causes aspergillus poisoning? |
|
Definition
Aspergillus flavus makes the toxin aflatoxin which contaminates food supplies
Causes liver damage and cancer |
|
|
Term
| What is the clinical form of Aspergillus? |
|
Definition
|
|
Term
| What is the leading cause of yeast infections? |
|
Definition
|
|
Term
| How is Candida albicans acquired? |
|
Definition
Endogenously
It's part of the normal flora |
|
|
Term
| What are the characteristics of Candida albicans under direct examination? |
|
Definition
Yeast and pseudohyphae
Cells usually exhibit budding
Pseudohyphae are constricted at ends and remain linked like sausages |
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|
Term
| What are the Candida albicans germ tube test results? |
|
Definition
| Positive, usually sufficient for ID |
|
|
Term
| What does Candida albicans look like on cornmeal agar? |
|
Definition
| Produces blastoconidia, pseudohyphae, true hyphae and chlamydoconidia |
|
|
Term
| What are the Candida albicans urease results? |
|
Definition
|
|
Term
| Cryptococcus neoformans is a major cause of oppurtunistic infections in what group? |
|
Definition
|
|
Term
| What is the reservoir for Cryptococcus neoformans? |
|
Definition
| Soil contaminated with pidgeon droppings |
|
|
Term
| What are the diseases caused by Cryptococcus neoformans? |
|
Definition
Pneumonia
Meningitis
Fungemia
|
|
|
Term
| What is the colonial appearance of Cryptococcus neoformans? |
|
Definition
|
|
Term
| What are the Cryptococcus neoformans germ tube test results? |
|
Definition
|
|
Term
| What does Cryptococcus neoformans look like on cornmeal agar? |
|
Definition
| Does not produce pseudohyphae or true hyphae |
|
|
Term
| What are the Cryptococcus neoformans urease results? |
|
Definition
|
|
Term
| What does Pneumocystis jiroveci cause in AIDS patients? |
|
Definition
|
|
Term
| What is the infective stage of Pneumocystis jiroveci? |
|
Definition
| Cyst that contains up to eight spores |
|
|
Term
| What kind of parasites are Microsporidia? |
|
Definition
| Unicellular and obligate intracellular |
|
|
Term
| Which Microsporidia are human pathogens? |
|
Definition
| Enterocytozoon bieneusi and Encephalitozoon intestinalis |
|
|
Term
| What kind of infections do Microsporidia cause? |
|
Definition
| Castrointestinal infections |
|
|
Term
|
Definition
A polyene macrolide antifungal agent
Drug of choice for serious systemic infections |
|
|
Term
| Which antifungal agents are polyene macrolides? |
|
Definition
| Amphotericin B and Nystatin |
|
|
Term
| Why is Amphotericin B callwed "amphoterrible"? |
|
Definition
| It has very serious side effects such as nephrotoxicity |
|
|
Term
| What are the antifungal agents? |
|
Definition
| Polyene macrolides (Amphotericin B and Nystatin), azole drugs, Griseofulvin and potassium iodide |
|
|
Term
| What is the causative agent of superficial mycoses? |
|
Definition
|
|
Term
| What disease does Malassezia furfur cause? |
|
Definition
|
|
Term
| What does Malassezia furfur look like in a KOH preparation? |
|
Definition
Spaghetti and meatball appearance
Septate hyphae
Budding yeast |
|
|
Term
| What are the causative agents of dermatophytosis? |
|
Definition
| Trichophyton, Microsporum and |
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