Mycology

Question 1

what are the three types of fungi?

Answer 1

yeasts, molds, and dimorphic

Question 2

what are some general fungi characteristics?

Answer 2

eukaryotic, chitin in cell walls, uni or multicellular, non-photosynthetic, obligate anaerobes, decomposers of dead material

Question 3

what are the superficial mycoses?

Answer 3

yeasts - trichosporin, malassezia

Question 4

what are the cutaneous mycoses?

Answer 4

molds - trichiophyton, epidermophyton, and microsporum

Question 5

what is chitin?

Answer 5

a polysaccharide that has long chains of N-acetylglucosamine

Question 6

what does the fungal membrane contain that is a good drug target?

Answer 6

ergosterol

Question 7

what are the two ways that yeast reproduce?

Answer 7

budding or binary fission

Question 8

what do you call networks of hyphae?

Answer 8

mycelium

Question 9

what is the purpose of septa in hyphae?

Answer 9

to make compartment but not discrete cells - have pores that allow passage of material

Question 10

what are spores?

Answer 10

something that all molds can make through mitosis or meiosis that allow dispersal of genetics and dormancy if conditions are unfavorable

Question 11

what is a germ tube?

Answer 11

a small immture hyphae that grows from a germinating spore

Question 12

what are methods to visualize fungi using microscopy?

Answer 12

KOH, calcoflour white, india ink, methenamine silver

Question 13

what is sabouraud’s agar?

Answer 13

inhibits bacterial growth, but promotes fungal growth

Question 14

what are three classes of antifungal treatments?

Answer 14

azoles, polyenes, echinocandins

Question 15

what do azoles do?

Answer 15

they inhibit synthesis of ergosterol

Question 16

what do polyenes do?

Answer 16

one example is amphotericin

they bind to ergosterol and make pores, causing osmotic death

Question 17

what do echinocandins do?

Answer 17

they block cell wall synthesis by inhibiting the synthesis of beta-glucan

Question 18

what are some examples of azoles?

Answer 18

fluconazole, voriconazole, itraconazole

Question 19

what are some side effects of azoles?

Answer 19

heptotoxicity is rare, voriconazole can lead to visual disturbances or hepatitis

Question 20

what are some examples of polyenes?

Answer 20

liposomal amphotericin B, nystatin (topical)

Question 21

what are some side effects of polyenes?

Answer 21

renal toxicity, chills, headache

Question 22

what are side effects of echinocandins?

Answer 22

GI effects, flushing

Question 23

what are some endothelial defenses to fungi?

Answer 23

dectin-1 - a PAMP that recognizes beta-glucan

defensins

Question 24

what do neutrophils protect against?

Answer 24

molds

Question 25

what do Th1 cells protect against?

Answer 25

intracellular fungi

Question 26

what do Th17 cells protect against?

Answer 26

mucosal fungal infections

Question 27

what are characteristics of superficial mycoses?

Answer 27

colonized keratinized outer layer of hair, skin, nails; noninflammatory; easy to treat

Question 28

what are characteristics of cutaneous mycoses?

Answer 28

invade/colonize in epidermis and cause inflammatory response

Question 29

what is the major superficial mycosis?

Answer 29

pityriasis versicolor (aka tinea versicolor)

Question 30

what are the two species that cause pityriasis versicolor?

Answer 30

malassezia furfur and globosa

Question 31

what diagnostic tool can be used for pirtyriasis versicolor?

Answer 31

wood's lamp - appears yellow-green

Question 32

what is does pityriasis versicolor look like microscopically?

Answer 32

yeast-like cells and pseudohyphae

Question 33

what is the treatment for pityriasis versicolor?

Answer 33

topical or oral azoles, selenium sulfide shampoo

Question 34

how do you identify cutaneous mycoses based on microscopy?

Answer 34

the presence of macro and microconidia

Question 35

what are some examples of cutaneous mycoses?

Answer 35

tinea, athlete's foot, ringworm

Question 36

what a mycosis that affects your nails?

Answer 36

tinia unguium aka onchomycosis

Question 37

how do you treat skin cutaneous mycoses?

Answer 37

topical azoles and terbinafine

Question 38

how do you treat hair and nail cutaneous mycoses?

Answer 38

oral azoles, terbinafine, and griseofulvin (hepatotoxicity)

Question 39

what is sporotrichosis?

Answer 39

a subcutaneous mycosis that is caused by a dimorphic fungus that lives in soil and vegetation

Question 40

what is a special microscopic determinant of sporotrichosis?

Answer 40

splendore-hoeppli phenomenon in which you see a pink granulomatous center surrounded by a starburst

Question 41

what is the treatment for sporotrichosis?

Answer 41

itraconazole, KI

Question 42

how does sporotrichosis spread?

Answer 42

along the lymphatics, leaving lesions as it travels

Question 43

what is chromomycosis?

Answer 43

a subcutaneous fungal infection that manifests with warty/nodular lesions that is more common in the tropics

Question 44

what are some microscopic characteristics of chromomycosis?

Answer 44

muriform cells - brown with septation (aka Medlar bodies); often present with granulomatous inflammation

Question 45

how do you treat chromomycosis?

Answer 45

itraconazole, terbinafine, local heat, cryotherapy, surgery contraindicated

Question 46

what is eumycotic mycetoma?

Answer 46

a deep, serious subcutaneous infection manifesting by localized swelling and discharege from sinuses containing black granules

Question 47

what are some possible fungi that cause eumycotic mycetomas?

Answer 47

madurella, fusarium, acremonium, exophiala, scedosporium

Question 48

what is treatment for eumycotic mycetomas?

Answer 48

antifungals, surgery maybe - oftentimes amputation is bad enough