Unit 4- Dermatophytes

Question 1

Dermatophytes

Answer 1

Molds infecting keratinized epidermal structures, ringworm

Question 2

Nonparasitic State Morphology

Answer 2

Septate branching hyphae called mycelium, asexual conidia in aerial mycelium, micro and macroconidia, varying hyphae shapes

Question 3

Parasitic State Morphology

Answer 3

Only hyphae and arthrospores are seen, sexual spores absent

Question 4

Dermatophyte Culture

Answer 4

Sabourads dextrose agar

Question 5

Woods Light

Answer 5

Ultraviolet light that causes M canis to have green fluorescence

Question 6

Dermatophyte Pathogenesis

Answer 6

Proteolytic enzymes, inflammation, high iron influx, infectious conidium reaches defect in stratum corneium, germ tube develops, hyphae grows into arthroconidia, hair invasion causes ringworm, germination with spore fomration

Question 7

Dermatophyte Pathogenesis

Answer 7

Proteolytic enzymes, inflammation, high iron influx, infectious conidium reaches defect in stratum corneium, germ tube develops, hyphae grows into arthroconidia, hair invasion causes ringworm, germination with spore formation

Question 8

Ectothrix

Answer 8

Accumulation of arthroconidia outside hair shaft

Question 9

Endothrix

Answer 9

Accumulation of arthroconidia inside hair shaft

Question 10

Dermatophyte Immunity

Answer 10

Humoral is limited, cellular decisive in protection and recovery

Question 11

Dermatophyte Diagnosis

Answer 11

M. canis and audouini emit fluorescence under woods lamp, skin scrapings and hair samples, lacrophenol cotton blue, SAD agar, PCR for chitin synthase 1 gene

Question 12

Microsporum canis

Answer 12

Mostly zoophilic but can spread to humans, majority of canine and feline ringworm, fluorescence, small ectothrix spores, white colonies with characteristic yellow reverse

Question 13

Microsporum gypseum

Answer 13

Many hosts, large ectothrix spores, fast growing colonies

Question 14

Trichophyton erinacei

Answer 14

Ringworm in hedgehog, rodents, dog, and humans, ectothrix spores, white colonies

Question 15

Trichophyton equinum

Answer 15

Ringworm in equine and dog, swelling, ulcers, and alopecia, large ectothrix spores, white colonies with pink/brown reverse

Question 16

Trichophyton verrucosum

Answer 16

Ringworm in cattle, large chained ectothrix spores, fluorescence in cattle but not human, slow growing folded colonies