Agents of Cutaneous Mycoses Flashcards
Enumerate the 3 causative agents of dermatophytosis.
1) Trichophyton
2) Microsporum
3) Epidermophyton
General term for causative agents of dermatophytosis.
dermatophytes
General term for diseases associated with dermatophytes.
dermatophytosis
– a fungal disease of the keratinized tissue of humans
– keratinophilic
dermatomycoses
What are the 2 sizes of reproductive cells produced by dermatophytes?
microconidia and macroconidia
What type of reproduction is seen in dermatophytes?
heterothallic
What type of reproduction whereby it requires the combination of two distinct mating types?
heterothallic
Identify the type of dermatophyte based on habitat:
- produce large numbers of conidia
- most readily identified species
geophilic
Identify the type of dermatophyte based on habitat:
- soil
geophilic
Identify the type of dermatophyte based on habitat:
- typically adapted to live on animals
- Fewer conidia are produced
zoophilic
Identify the type of dermatophyte based on habitat:
- adapted exclusively to human hosts
- almost always encountered as agents of human disease
- infections are seldom inflammatory
anthropophilic
Identify the causative agent.
Tinea favosa
Trichophyton schoenleinii
Identify dermatophytosis:
✓ crusty lesions
✓ scutula (crusty, cup-shaped flakes) are formed
✓ hair loss, scar tissue formation
Tinea favosa
Identify dermatophytosis:
- infection of the nails
- subungual
- thick
- discolored
- flaky
Onychomycosis
Identify dermatophytosis:
- athlete’s foot
- contact with infected skin scales
- can be genetic
Tinea pedis
Identify dermatophytosis:
- extensive scaling
- fissuring
- erythema
Tinea pedis
What is the other name for athlete’s foot disease?
Moccasin foot
Identify the dermatophyte.
▪ Favic Chandelier
▪ Moose Antler Hyphae
Trichophyton schoenleinii
Describe the colony morphology of Trichophyton schoenleinii.
suede-like and deeply folded
What form of tinea capitis is common among children and colonizes the outer portion of the hair shaft (ectothrix)?
Gray patch ringworm
What form of tinea capitis colonizes the inside (endothrix) of the hair shaft whereby weak, brittle, infected hair shafts break off at the scalp, leaving the black dot stubs?
Black dot ringworm
Identify the dermatophyte.
- anthropophilic
- Microconidia: chlamydospores
- Macroconidia: odd shaped and has chlamydoconidia-like swellings
Microsporum audouinii
Identify the dermatophyte.
- Microconidia: tear-shaped or balloon-shaped
- Macroconidia: cylindrical
Trichophyton tonsurans
What treatments may be given to patients with onychomycosis?
terbinafine and itraconazole
Identify the dermatophyte.
- produces only 1 size of conidia
Epidermophyton floccosum
Identify the dermatophyte.
- yellow to yellow-tan
- flat with feathered edges
- small in diameter
Epidermophyton floccosum
Identify the dermatophyte.
- zoophilic
- spindle-shaped macroconidia (3-15 cells)
Microsporum canis
Identify the dermatophyte.
- fluffy and white colonies
- reverse side: lemon-yellow pigment, especially on potato dextrose agar
Microsporum canis
Identify the dermatophyte.
- geophilic
- macroconidia: cigar-shaped, rounded ends (6 cells)
Microsporum gypseum
Identify the dermatophyte.
- tan to buff conidial masses are typical of fresh
isolates - abundant brown to red pigment can form beneath some strains, but others remain colorless.
Microsporum gypseum
Identify the dermatophyte.
- slow-growing anthropomorphic dermatophyte
- cottony white colonies
Microsporum audouinii
Identify the dermatophyte.
- globose and grape-like microconidia
Trichophyton mentagrophytes
Identify the dermatophyte.
- pencil-shaped macroconidia (3-8 cells)
Trichophyton rubrum
What is the culture media used for Trichophyton tonsurans?
Sabouraud dextrose agar
What is the leading cause of tinea capitis in children?
Trichophyton tonsurans
