Mycology Flashcards
Culture medium of fungi
Saboraud’s agar
Low pH 5.6 inhibits growth of bacteria but permits growth of filamentous fungi and yeast
Impregnated with chloramphenicol and gentamicin to inhibit growth of other bacteria
Saboraud’s agar
Used to dissolve tissue material leaving the alkali resistant fungi intact
10% KOH
Fungal wall constituent
Chitin
Ergosterol
Beta glucan
Mannoproteins
Protein found in exoskeleton and wall of fungi
Chitin
Sterol of the cell membrane of fungi and cell wall of protozoans regulates permeability and fluidity of fungal cell wall
Ergosterol
Most abundant polysaccharides of the fungal wall
Betaglucans
Opportunisitc mycosis
Candidiasis
Cryptococcus neoformans
Histoplasma
Pneumocystis carinii
Fungi that infect only the keratinized tissue (skin, hair and nails)
Cutaneous mycosis
Cutaneous mycosis
Microsporum
Trichophyton
Epidermophyton
Affects skin, hair and nails
Trichophyton three
Affects only skin and hair
Microscporum
Affects only skin and nails
Epidermophyton
Ringworm of scalp
Tinea capitis
Ringworm of bearded region
Tinea barbae
Ring worm of glabrous skin
Tinea corporis
Jock itch
Tinea cruris
Athlete’s foot
Tinea pedis
Most serious of tinea capitis
Tinea favosa/favus
Most common cause of outbreaks of tinea capitis in children
Main cause of endothrix
Trichophyton tonsurans
Dermatophyte infections that invade hair shaft and internalize into hair cell
Endothrix
Dermatophyte infectikn confined to the hair surface
Ectothrix
Severe tinea capitis
Tinea favosa
Trichophyton schoenleinii
Causes tinea favus
Tinea capitis presenting with crust on the scalp
Most serious form causing permanent scarring and scalp hair loss
Trichophyton schoenleinii
Tinea favus
Zoophilic tinea capitis
Microsporum canis
Trichophyton mentagrophytes
Young child showing a large circular erythematous scaly lesion with a raiser border on the nose
Microsporum gypseum
Tinea barbae
Trichophyton verrucosum
Trichophyton mentagrophytes
Trichophyton rubrum
Most prevalent systemic mycosis
Candidiasis
Candida albicans
Appear as yeast or pseudohyphae
Germ tube formation in serum at 37 deg
Candida albicans
Grow as oval, budding yeast cell (3-6 um in size)
Also form pseudohyphae when buds continue to grow
Candida albicans
On agar media or within 24h at 37 deg or room temperature
Soft, cream-colored colonies with a yeasty odor
Candida albicans
Can infect kidneys
Attach to prosthetic heart valves or produce candidal infections almost anywhere (eg arthritis, meningitis, endopthalmitis)
Oral candidiasis
Vaginal
Candida
Cottage cheese discharge
DM
Vaginal candidiasis
Esophageal candidiasis risk factor
Radiation
Chemotherapy
Candida tx
Nystatin
Thrush and mucocutaneous form of candidiasis Tx
Topical Nystatin
Oral Ketoconazole or Fluconazole
Systemic candidiasis tx
Amphotericin +/- oral flucytosine
AIDS
Pigeon
Yeast from CSF stained with india ink
Meningitis
Cryptococcus neoformans
Bird or bat dropping
Histoplasma
Pigeon dropping
Eucalyptus tree
Encapsulated yeast cell (India ink)
Meningitis
Cryptococcus neoformans
Cryptococcus neoformans Dx
India ink
Cryptococcal antigen latex agglutination (CALAS)
HIV defining illness (CD <200)
CD <100 this infection sets in
Cryptococcus neoformans
Severe interstitial pneumonia in immunocompromised patients especially AIDS patients
Previously protozoan -> 1988 yeast
Pneumocystis carinii
Pneumocystis jiroveci