Mycology

Question 1

Dimorphic fungi

Answer 1

→yeast @ 37°c
→hyaline septate molds @ 25-28°c
→ histoplasma capsulatum
→ sporothrix schenkii.
→ blastomyces dermatitidis.
→ penicillium marneffi

• lab diagnosis (sporothrix schenkii)
1. Microscopy:
→ biopsy - h&e stain
→ cigar shaped yeast surrounded by splendor- hoeplii phenomenon ⇒ Eosinophilic radiating spicules
→ asteroid body.
2. Culture:
→ SDA & blood agar.
→25-28°c ⇒ hyaline septate molds with Rosetts of conidia.
→ 37°c ⇒ yeast form, white creamy, turn brown-black in 10-14 days.
3. Yeast conversion test: Proove dimorphism.
4. Serology: LAT for serum antibodies
5. Skin test -type 4 hypersensitivity reaction.

Question 2

Fungi imperfecti.

Answer 2

→ aka phylum deuteromycetes
→ septate hyphae
→ most fungi of medical importance.
→ sexual state- absent/ unidentified.
→ Not fit in common taxonomical classification.
→ asexual form- spores.

Question 3

Superficial mycotic infections.

Answer 3

1. Tinea / pityriasis versicolor- malassezia globosa & M. furfur
2. Tinea nigra- hortae werneckii
3. Piedra- white: trichosporon sp, T.beigelli, T.asahii
   black: piedrae hortae
4. Deamatophytosis/ Tinea/ ring worm - trichophyton, epidermophyton, microsporum