05 - Mycology Flashcards
Identify: fungal infection associated with pseudomembranous pharyngitis:
Candida
Two basic fungal forms:
- yeast - single-celled
2. mold - with hyphal elements
Term: the ability to reproduce as one of either of the two basic forms, depending on the temperature:
What forms are assumed in culture media and in live tissues in these kinds of organisms?
thermal dimorphism
- molds on culture medium at room temperature
- yeasts on live, infected tissue
Two types of host response to fungal infection:
- granulomatous
- pyogenic
- toxin of Amanita:
- What is the effect?
- amanitin and phylloidin
- liver necrosis
- toxin of Aspergillus flavus:
- What is the effect?
- aflatoxin
- G:C->T:A mutation, leading to liver cancer
term for allergic reaction to spores of Aspergillus fumigatus:
allergic bronchopulmonary aspergillosis
Identify: agar used in the culture of fungi:
Sabouraud agar - low pH inhibits growth of bacteria
This stain binds to the complex carbohydrate cell wall of fungi and lights up a bright blue white color:
Calcofluor white
This stain is primarily used for negative staining.
-What fungus is diagnosed using this stain?
Nigrosin
-Cryptococcus neoformans
Enumerate 3 important dermatophytoses:
- Microsporum canis
- Trichophyton tonsurans
- Epidermophyton floccosum
Another name for dermatophytoses:
ring worms
Term: an inflammatory reaction to dermatophytosis at a cutaneous site distant from the primary infection
dermatophytid reaction
How to diagnoses dermatophytoses:
- 10% KOH
- Sabouraud agar
- Wood lamp: green fluorescence
Treatment of dermatophytoses:
- local antifungal cream
- keep skin dry
- Identify: superficial skin infection presenting with hypopigmented areas.
- What causes the hypopigmentation?
- What fungal organism causes this condition?
- Treatment:
- Tinea versicolor
- azoleic acid
- Malasseizia furfur
- miconazole
Identify: This organism causes fungemia in premature infants on IV nutrition:
Malassezia furfur
Mechanism of transmission of Sporotrichosis:
rose thorn prick
Another name for sporotrichosis:
Rose gardener’s disease
Treatment of sporotrichosis:
itraconazole, or potassium iodide
Enumerate: the two morphologies of Coccidioides immitis, in which settings:
- mold in soil
- spherule in tissue
another term for Coccidioidomycosis:
Desert Rheumatism, a.k.a. San Joaquin valley fever
Mechanism of transmission of Coccidiodes:
inhalation of arthrospores
Symptoms of Desert Rheumatism:
Flu-like symptoms:
- fever
- arthralgia
- malaise
- cough/coryza
- headache
Two types of asexual spores in Histoplasma capsulatum:
- tuberculate macroconidia
- microconidia
mechanism of transmission of Histoplasma:
-inhalation of airborne microconidia
describe the pathogenesis of Histoplasma:
Inhaled histoplasma microconidia develop into yeasts inside macrophages, and the spreads to the liver and the spleen
mechanism of transmission of Blastomyces dermatitidis
inhalation of conidia
- Paracoccidioides brasiliensis preferentially infects which subgroup of the population?
- Explain
- preferentially infects males
- Estrogen and progesterone are found to be protective
mechanism of transmission of Paracoccidioides brasiliensis
inhalation of conidia
morphologies of Candida albicans in serum, and in culture
- germ tubes in serum
- chlamydo-spores in culture
Enumerate: diseases of Candida in the immunocompetent (give 3)
- oral thrush
- vulvovaginitis
- onychomycosis
Manifestion of Candida infection in the immunocompromised:
pseudomembranous esophagitis
Identify: most common cause of fungal encephalitis
Cryptococcus neoformans
Enumerate: Diagnostic tests for Cryptococcus
- India ink preparation (negative staining)
2. CALAS (Cryptococcal antigen latex agglutination system)
How is cryptococcus transmitted?
grows abundantly in soil with lots of bird dropping; inhalation of airborne yeast cells
DOC for cryptococcal encephalitis:
amphotericin B + flucytosine
Morphologies of Aspergillus fumigatus:
exist only as molds!
How is Aspergillus transmitted?
inhalation of airborne conidia
Term for fungus balls:
Aspergilloma
Identify: Aspergillosis with asthmatic symptoms with expectoration of brownish bronchial plugs
allergic bronchopulmonary aspergillosis (ABPA)
Identify: organisms in Mucormycosis:
Rhizopus and mucor
Clinical presentation of mucormycosis:
rhino-orbital-cerebral infection with eschar formation
Enumerate: these (3) patients are at high risk for infection with Rhizopus and mucor
- Burn patients
- DKA patients
- leukemia
The major surface glycoproteins of this fungus undergoes programmed rearrangements:
Pneumocystis jiroveci
Diagnostic test for Pneumocystis jiroveci
Bronchoalveolar washings, then
- toluidine blue
- methenamine silver stain
mechanism of transmission of Pneumocystis jiroveci:
inhalation of cysts
At what CD4 count does Pneumocystis pneumonia occur?
CD4 < 200
Identify: what is the most common AIDS-defining illness?
Pneumocystis jiroveci pneumonia
DOC for Pneumocystis jiroveci pneumonia:
Trimethoprim-sulfamethoxazole
