Special Lab - Mycology Flashcards
these exhibit both yeast and filamentous forms
dimorphic fungi
- often dependent on incubation temp
this prevents the overgrowth of rapidly growing molds
cycloheximide
we use india ink to see the capsules of this organism
Cryptococcus
Mycosel agar
- for primary recovery of dermatophytes, pathogenic fungi, bacteria
- inhibits saprophytic fungi
- has chloramphenicol and cycloheximide
saprophyte
any organism that lives on dead organic matter, as certain fungi and bacteria
dermatophyte
parasitic fungus (mycosis) that infects the skin (tinea, ringworm, jock itch, athlete’s foot)
PHY or phytone yeast extract agar
media for yeast and other pathogenic fungi; inhibits dermatophytes due to chloramphenicol
T or F. CACs have hloramphenicol
T
The mode of transmission for these fungi is direct contact
Malassezia furfur
dermatophytes
mode of transmission of Candida sp
direct invasion or dissemination
tinea vesicolor
Malassezia furfur (may be the cause of dandruff)
Aspergillus
- inhalation
- lungs, eyes, skin, nails
- conidia
Penicillium
- inhalation
- superficial
- rare
- resp. sinusitis
Pneumocystis jirovecii
- inhalation
- PCP or pneumocystic pneumonia
Histoplasma capsulatum
- found in bat or bird feces
- inhalation
- infects lungs, BM, blood; conidia
T or F. Most fungi are obligate aerobes
T
PAS stain for fungi
stains polysaccharides in cell wall bright pink or magenta
GMS stain for fungi
for AP sections
stains fungi outline black
10% KOH for skin nails and hair
- breaks down keratin and skin layers to easily see fungi
- may be used with calcofluor white for easier ID
Lactophenol cotton blue
- stains darkly
- blue-coloured appearance of fungal spores + structures (like hyphae)
- may be used with KOH
calcofluor stain
fluorescence
- stain binds to cellulose/chitin on fungal cell wall
india ink or nigrosin
C. neoformans ID
- a negative stain; capsules seen as clearing
- latex agglutination more specific for ID
yeast and YLO
Candida spp, C. neoformans, M. furfur
Superficial Mycoses (dermatophytes and agents of tinea, tinea nigra and piedra)
NOTE: dermatophytes need keratinized tissue*
Tichophyton* Microsporum* Epidemophyton* M. furfur Candida spp
Opportunistic mycoses
Aspergillus Penicillium P. jirovecii C. neoformans Candida spp
Systemic Mycoses
level III
Coccoides immitis
Histoplasma capsulatum
Blastomyces dermatitidis
ringworm
tinea, a superficial fungal disease of vairous b ody parts
Which fungi exists in the mold phase in the saprophytic environment and tissue or parasitic phase in the host?
Histoplasma sp
a naturally occurring fungicide produced by the bacterium Streptomyces griseus.
cycloheximide
- Cycloheximide exerts its effects by interfering with the translocation step in protein synthesis, thus blocking eukaryotic translational elongation
