Superficial and Subcutaneous Mycoses and Dermatophytes (Exam 3)

What layers of the skin can superficial fungi infect?

- Epidermal

- Keratin

- Cuteneous/subcutaneous

What are some characteristics of the superficial mycoses?

- Non-invasive

- Outer body infections (skin, hair, nails)

- No inflammation caused

What are the fungi causing superficial mycoses?

- Trichosporon spp.

- Malassezia furfur

- Piedraia hortae

Trichosporon beigelii colonies

25C

Creamy white/yellow

Smooth/folding

Furrows

Trichosporon beigelii microscopic

How is Trichosporon beigelii transmitted?

Sharing combs and hairbrushes

Piedraia hortae colonies

25C

Green/black

Piedraia hortae microscopic

How is Piedraia hortae transmitted?

Sharing combs and hairbrushes

Malassezia furfur colonies

Malassezia furfur direct smear

Short hyphae with round yeast cells

Malassezia furfur in vitro

Bowling pins

Malassezia furfur is transmitted via ______.

Sharing combs, hairbrushes, razors, towels, skin products

Piedraia hortae is associated with ______ piedra.

black

Trichosporon beigelii is associated with ______ piedra.

white

What organism is associated with intralipid hyperalimentation and pityriasis/tinea versicolor?

Malassezia furfur

What are the growth requirements for Malassezia furfur?

Requires lipids (ex. olive oil)

37C

A dermatophyte is a fungus that can cause ______ disease.

skin

Ringworm is a fungal infection of the skin that appears in ______.

circular lesions

Microsporum audouinii colonies

Slow growth

Gray/white

Salmon reverse

Microsporum audouinii hyphae

Microsporum audouinii

Microsporum audouinii disease

Tinea capitis and Tinea corporis

Microsporum canis colonies

1-2 weeks

White/yellow

Microsporum canis

Microsporum canis disease

Affects dogs/animals

Microsporum gypseum colonies

1-2 weeks

Buff, cinnamon, powdery

Tan reverse

Microsporum gypseum

Microsporum gypseum disease

Various tineas

Trichophyton rubrum colonies

White. granular/fluffy, pink periphery

Deep red reverse

Trichophyton rubrum

Trichophyton rubrum disease

Various tineas

Trichophyton mentagrophytes colonies

Buff, flat, granular

Brown, red, yellow reverse

Trichophyton mentagrophytes

Trichophyton mentagrophytes disease

Various tineas

Trichophyton tonsurans colonies

Grey-white, suede, reverse mahogany

White, granular reverse colorless

Yellow, granular, reverse yellow

Trichophyton tonsurans

Trichophyton tonsurans disease

Tinea capitis mainly, other tineas

Epidermophyton floccosum colonies

1-2 weeks

Khaki yellow, velvety, center folded

Yello/brown reverse

Epidermophyton floccosum

Epidermophyton floccosum disease

Tinea pedis, Tinea cruris, Tinea corporis

What tests are used to differentiate between Trichophyton rubrum and Trichophyton mentagrophytes

- Microscopic morphology

- Colony morphology

- Urease (rubrum +, mentagrophytes -)

Tinea capitis site

Scalp

Tinea barbae site

Beard

Tinea corporis site

Body (general)

Tinea manuum site

Hands

Tinea unguium site

Nails

Tinea curris site

Groin (Jock Itch)

Tinea pedis site

Feet (Athlete's Foot)

Tinea imbricata site

Body (distinctive)

How are dermatophytes transmitted?

Sharing of combs, brushes, razors, etc.

What treatments can be used against dermatophyte infections?

Antifungals (ex. Clotrimazole, Itraconazole, Griseofulvin, Terbinafine)

Microsporum macroconidia

Pointed ends

Trichophyton macroconidia

Rounded ends

Baseball bat-shaped

Epidermophyton macroconidia

Club shaped

What are the three genera of molds associated with causing subcutaneous mycoses?

- Cladophialophora (Cladosporium) carrionii

- Phialophora verrucosa

- Fonsecaea pedrosi

Cladosporium sporulation

Tree

Phialophora sporulation

Flask

Acrotheca sporulation

A mycetoma is the ______.

puncture site

The disease mycetoma is a chronic ______ disease.

granulomatous

(Lower extremities, tropical)

Chromoblastomycosis is a cutaneous/subcutaneous infection caused by ______.

skin trauma

Chromoblastomycosis causes ______, cutaneous lesions.

warty

Cladosporium carrionii

Phialophora verrucosa

Fonsecaea pedrosi

Exophiala jeanselmei

Pseudallesheria boydii