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Flashcards in Microbiology Mycology - First Aid Deck (40)
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1
Q
Systemic mycoses can all cause...
A
pneumonia and can disseminate.
2
Q
All systemic mycoses are caused by...
A
dimorphic fungi:
-cold (20 C) = mold
-heat (37 C) = yeast

*The only exception is coccidioidomycosis which is a spherule (not yeast) in tissue.
3
Q
Treatment for Systemic Mycoses
A
Local infection: Fluconazole or Itracoazole
Systemic infection: Amphotericin B
4
Q
Systemic mycoses can mimic...
A
TB (w/ granuloma formation) but unlike TB, they have no person-to-person transmission.
5
Q
Systemic mycoses types (4)
A
1. Histoplasmosis
2. Blastomycosis
3. Coccidioidomycosis
4. Paracoccidioidomycosis
6
Q
Histoplamosis features (4)
A
-Mississippi and Ohio River valleys
-causes pneumonia
-macrophages filled with histo
-bird or bat droppings
7
Q
Blastomycosis features (4)
A
-states east of Mississippi river (and Central America)
-causes inflammatory lung disease and can disseminate to bone and skin
-forms granulomatous nodules
-broad-base budding
8
Q
Coccidioidomycosis features (6)
A
-Southwest US
-causes pneumonia and meningitis
-can disseminate to skin and bone
-spherule filled with endospores
-erythema nodosum (desert bumps)
-arthralgias (desert rheumatism)
9
Q
Coccidioidomycosis rates increase after...
A
earthquakes which causes spores in the dust to be thrown up into the air.
10
Q
Paracoccidioidomycosis features (2)
A
-Latin America
-budding yeast w/ "captain's wheel" formation
11
Q
Tinea versicolor is caused by...
A
Malassezia furfur which degrades lipids producing acids that damage melanocytes and cause hypopigmented/hyperpigmented patches.
12
Q
Tinea versicolor occurs in...
A
hot, humid weather.

Has a "spaghetti and meatball" appearance.
13
Q
Treatment for tinea versicolor
A
topical miconazole, selenium sulfide
14
Q
Other tineae (cutaneous mycoses) include...
A
tinea pedis (foot)
tinea cruris (groin)
tinea corporis (ringworm, on body)
tinea capitis (head, scalp)
tinea unguium (onychomycosis on nails)
15
Q
Dermatophytes include (3):
A
1. Microsporum
2. Trichophyton
3. Epidermophyton
16
Q
Dermatophytes cause..
A
pruritic lesions with central clearing resembling a ring.
17
Q
In a KOH prep, dermatophytes show as...
A
mold hyphae, not dimorphic.
18
Q
Opportunistic fungal infections (6)
A
1. Candida albicans
2. Aspergillus fumigatus
3. Cryptococus neoformans
4. Mucor and Rhizopus
5. Pneumocystis jirovecii
6. Sporothrix schenckii
19
Q
Candida albicans causes:
A
-oral and esophageal thrush
-vulvovaginitis
-diaper rash
-endocarditis in IV drug users
-mucocutaneous candidiasis
20
Q
Treatment for Candida albicans
A
Vaginal - topical azole
Oral/esophageal - fluconzaole, caspofungin
Systemic - fluconazole, Amphotericin B, Caspofungin
21
Q
Aspergillus fumigatus casues...
A
Allergic Bronchopulmonary Aspergillosis: associated with asthma and CF; may cause bronchiectasis and eosinophilia

Aspergillomas in lung cavities, esp after TB.
22
Q
Some species of Aspergillus produce...
A
aflatoxins which are associated with hepatocellualr carcinoma.
23
Q
Candida albicans features (3)
A
-dimorphic yeast
-pseudohyphae and budding yeasts at 20 C
-germ tubes at 37 C
24
Q
Aspergillus fumigatus features (4)
A
-invasive esp in those with chronic granulomatous disease
-septate hyphae that branch at acute (45 degree) angles
-conidiophore with radiating chains of spores
-not dimorphic
25
Q
Cryptococcus neoformans causes...
A
cryptococcal meningitis (soap bubble lesions in the brain) and cryptococcosis.
26
Q
Cryptococcus neoformans features
A
-heavily encapsulated yeast
-not dimorphic
-soil, pigeon droppings
-wide capsular halos and unequal budding
27
Q
Cryptococcuus neoformans is acquired through...
A
inhalation with hematogenous dissemination to the meninges.
28
Q
The most specific test for cryptococcus neoformans is...
A
latex agglutination test which detects polysaccharide capsular antigen.
29
Q
Mucor and Rhizopus cause...
A
mucormycosis mostly in ketoacidotic diabetic and leukemic pts.
30
Q
Mucor and Rhizopus fungi proliferate in...
A
blood vessel walls when there is excess ketone and glucose, penetrate the cribiform plate and enter the brain. This causes rhinocerebral, frontal lobe abcesses.
31
Q
Signs of Mucor and Rhizopus infection
A
-HA
-facial pain
-black necrotic eschar on face
-cranial nerve involvement
32
Q
Treatment for Mucor and Rhizpus
A
Amphotericin B
33
Q
Mucor appearance
A
irregular, broad, nonseptate hyphae branching at wide angles
34
Q
Pneumocystis jirovecii causes...
A
pneumocystis pneumonia, a diffuse interstitial pneumonia.
35
Q
Pneumocystis jirovecii features
A
-inhaled
-usually asymptomatic
-disc-shaped yeast forms on methenamine silver stain of lung tissue
36
Q
Treatment/prophylaxis for pneumocystis jirovecii
A
TMP-SMX, pentamidine, dapsone (prophylaxis only), atovaquone (prophylaxis only)
37
Q
Start prophylaxis for pneumocystits when...
A
CD4 count drops to less than 200 in HIV pts.
38
Q
Sporothrix schenckii causes...
A
sporotrichosis. When spores are traumatically introduced into the skin, typically by a thorn (rose gardener's disease), it causes a pustule/ulcer with nodules along draining lymphatics.
39
Q
Sporothrix schenckii features (3)
A
-dimorphic
-cigar-shaped budding yeast
-lives on vegetation
40
Q
Treatment for Sporothrix schenckii
A
Itraconazole or Potassium iodide