Mycology

Question 1

Dimorphic or Diphasic

Answer 1

Mycelial (filamentous form) – free living, saprophytic form in nature. Grows at 30 C.

“Yeast-like” phase when growing at 37 C.

Question 2

7 Medically Important Dimorphic Fungi

Answer 2

Histoplasma capsulatum

Blastomyces dermatitidis

Coccidioides immitis

Paracoccidioides brasiliensis

Sporothrix schenckii

Black molds involved in chromoblastomycosis

Penicillium (now Talaromyces) marneffei

Question 3

What is this?

Answer 3

Talaromyces marneffei

Question 4

Culture Media for Mycology

Answer 4

Selective SAB with chloramphenicol (keep bacteria away)

BBHI with gentamicin and chloramphenicol (to convert anything for 37)

Question 5

GMS Stain

Answer 5

Gomori/Grocott Methanamine Silver Stain

Fungal walls stain black….so can collage fibers RBC’s

Question 6

PAS

Answer 6

Periodic Acid Sciff Stain

Fun gal cell walls stain pink/red

Question 7

Mucicarmine Stain

Answer 7

Capsular Polysaccharide

Question 8

Eumycotic mycetoma

Question 9

Chromoblastomycosis

Question 10

Sporotrichosis

Answer 10

Sporothrix schenckii

Question 11

Rhinosporidiosis

Answer 11

NOW AQUATIC PROTISTAN PARASIT

Question 12

Lobomycosis

Question 13

Tinea versicolor

Question 14

White Piedra

Question 15

Black Piedra

Question 16

Crytococcosis

Answer 16

Cryptococcus neoformans

Question 17

Hyalohyphomycosis

(light-colored, filamentous fungi)

Question 18

Phaeohyphomycosis

(“black molds”)

Question 19

Zygomycosis

Question 21

Histoplasmosis

Answer 21

• Guano and debris from birds + bats
• 95% cases flu-like syndrome

Microbiology

• Culture at 30C
• Dimorphic!

Tuberculated macroconidia –> pathoneumonic!

Question 22

Blastomycosis

Answer 22

• Dimorphic fungi
• Clinical: Pulmonary, disseminates to skin.
• Eastern 1/3 of US
• Pear-shaped “pyriform” conidia resembling “Lollipops”

At 37C – Broad Based Budding!

Question 23

What is this fungi?

Answer 23

Blasto at 30 C

Question 24

Coccidioides (30 C)

Answer 24

• SW USA, desert sands
• Sx: “Valley fever”
• Culture at 30C
  
  • barrel-shaped arthroconidia with dead cells in between
• Culture at 37C
  
  • Tissue dimorphic
  • Thick-walled spherules with endospores

Question 25

Cocciodioes at 37 C

Answer 25

• Thick-walled spherules with endospores
• 10-80 um wide (50 um)

Question 26

Rhinosporidium seeberi

Answer 26

• Similar to Cocciodios at 37 C
• However, spherules are 200 um!
• Mucicarmine +

Question 27

Paracoccidioides brasiliensis

Answer 27

• “South American Blastomycosis”
• Pulmonary/disseminated disease
• At 37C, Mariner’s wheel