Term
| What is the fungal sterol? What do we target it with? |
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Definition
-Ergosterol
-Imidazole antifungals inhibit synthesis
-Polyene antifungals bind it directly (better than cholesterol) |
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Term
| What word do we use to describe fungi's ability to live on dead material? On living things? |
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Definition
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Term
| What are dimorphic fungi? |
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Definition
-Able to convert between hyphal and yeast forms depending on temperature (25C for mold, 37C for yeast)
-To remember "Mold in the cold, yeast in the beast" lol
Types;
-Blastomyces (systemic)
-Histoplasma (systemic)
-Coccidioides (systemic)
-Sporothrix (Sub Q)
Mnemonic; Body Heat Changes Shape |
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Term
| When your talking about hyphae, what terms do we use to describe their coloration? What do we call a whole mat of hyphae? |
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Definition
-Dematiaceous; gray or olive colored
-Hyaline; clear
-Mycelium (mold)
-Also note, hyphae can be septate or aseptate |
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Term
| What are pseudohypae and where do we see them? |
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Definition
-Pseudohyphae are pinched at each septum and formed by exaggerated budding without detachment
-Candida albicans has this appearance |
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Term
| What is the name we use for spores? |
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Definition
-Conidia
-Note, for some reason, Kaplans spore discussion sucks, so use the mycology cards from class to get a better idea on them
-They look specifically at blastoconidia (buds off), arthroconidia (breaks off), and spherules and endospores |
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Term
| What are some of the microscopic diagnostic test we use (5)? |
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Definition
1. KOH mount is the most common, esp. for cutaneous
2. PAS (periodic AS); look hot pink
3. India ink; for Cryptococcus neoformans in CSF
-Being replaced with *latex particle agglutination (uses Ig) because India ink has bad sensitivity (only 50%)
-Will look colorless with halos of capsule on dark background
4. Silver stain; for Pneumocystis
5. Calcofluor white; for wet mounts of scrapings; uses fluorescent microscope
-Bright blue-white on dark background |
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Term
| What do we use to culture? |
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Definition
-Sabourauds agar
-Or blood agar
-Both loaded with antibiotics |
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Term
| What is the type of fungi that causes superficial skin infections? What is the disease called? |
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Definition
-Tinea versicolor (pityriasis) is caused by **Malassezia furfur
-This is an infection of only the dead cell layer (keratin layer)
-Wikipedia is saying M. *globosa is the main culprit |
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Term
| What does tinea versicolor look like macroscopic & microscopically? How do we prepare it to view with a microscope? |
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Definition
-Usually it is hypopigmented blotches on the skin, but may also be hyperpigmented
-Under a microscope it looks like "spaghetti and meatballs" (Him? lol) with a mix of yeast and septate hyphae
-Usually we would do a **KOH mount
-Can also look at it under *woods lamp to see coppery-orange fluorescence |
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Term
| What other condition has Malassezia furfur been associated with? |
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Definition
| -Fungemia (fungi in blood) in premees on IV lipid supplement |
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Term
| What are the three genera of fungi we associate with cutaneous infections (not just superficial)? What cutaneous structure do they infect? What is the name used for fungi that infect the skin? |
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Definition
Three types of dermophytes;
1. Trichophyton - skin, hair, nails
2. Microsporum - skin, hair
3. Epidermophyton - skin, nails
-Think "tri" for three, for the first |
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Term
What are the infections of;
-Scalp
-Beard
-Skin/body
-Balls
-Foot
-Nails |
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Definition
-Scalp; tinea capitis
-Beard; tinea barbae
-Skin/body; tinea corporis
-Balls; tinea cruris (jock itch)
-Foot; pedis (athletes foot)
-Nails; tinea unguium
-Tinea capitis is especially bad when caused by favus, which causes permanent baldness |
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Term
| How will the dermatophytes look under the microscope? How do we prep. What other method can we use to diagnose? |
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Definition
-Hyphae and arthroconidia (spores from broken off segments)
-Prep with a normal KOH mount
-Can also just use woods lamp and look for bright yellow-green fluorescence |
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Term
| How do we treat dermatophyte infections? |
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Definition
-We use topical imidazoles or tolnaftate
-Can also give oral griseofulvin or imidazoles (when topical burns or something) |
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Term
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Definition
-It is short for dermatophytID reaction where there is an allergic response to circulating antigens
-Usually we will get swelling of hands when feet are infected, etc. |
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Term
| What is the one most important type of fungi that causes subcutaneous infections? What are those infections? |
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Definition
Sporothrix schenckii
1.**Sporotrichosis (rose gardeners disease); usually get from traumatic implantation from thorn, wire, etc.
-Can be subcutaneous or lymphocutaneous
2. Pulmonary sporotrichosis (alcoholic rose gardener's disease lol); usually seen in homeless |
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Term
| How do we identify sporothrix schenckii? |
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Definition
-It is dimorphic, but will exist as yeast in the body
-They are *cigar-shaped yeast
-In the environmental form they are hyphae with a bunch of conidia budded off all over the place |
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Term
| How do we treat sporotrichosis? |
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Definition
| -We use *itraconazole or *amphotericin B (toxic) |
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