MYCOSES (Opportunistic mycoses)

Question 1

Dimorphic’ Forms pseudohyphae and budding yeasts at 20C’ germ tubes at 37C:

Answer 1

Candida albicans

Note: Remember CANDIDIASIS:
- Gern tube test (+)
- Cornmeal agar + tween 80 (+)
- Rapid urease test (-)
- Growth @ 42C

Question 2

Monomorphic septate hyphae that branch at 45 degrees acute angle:

Answer 2

Aspergillus fumigatus

Question 3

Heavily encapsulated yeast. Not dimorphic.

Answer 3

Cryptococcus neoformans

Remember Cryptococcosis:
- India ink
- Bird seeded agar
- L-DOPA ferric citrate test
- Rapid urease test (+)

C. neoformans
- Nitrate (-)
- Urease (+)
- Inositol (+)

Question 4

Irregular, broad, non septate hyphae branching at wide angles

Answer 4

Mucor and Rhizopus spp.

Question 5

Causes Pneumocystis pneumonia (PCP), a diffuse intertitial pneumonia; yeast-like fungus (originally classified as protozoan)

Answer 5

Pneumocystis jiroveci (formerly P. carinii)

Question 6

What is the specimen of choice for the diagnosis of Pneumocystis pneumonia:

Answer 6

Bronchioalveiolar lavage
- Disc shape yeast seen on methenamine silver stain of lung tissue