MYCO & VIRULOGY L2 (Prelim- Subcutaneous & Cutaneous) Flashcards
Cute kay ko. I heart ma'am jo 4evah <333
Infects outermost layer of skin or hair
Superficial mycoses
Causes patchy lesions/ scaling, dandruff, and prevalent during warm weather
Malassezia furfur
Appearance of an outer ring of a progressing infection
Malassezia furfur
Common sites of Malassezia furfur
- face
- chest
- trunk
- abdomen
Appearance of Malassezia furfur under KOH
- “spaghetti and meatballs fungus”
- budding yeasts
Positive for Malassezia furfur in wood lamp
Yellow fluorescence
Causative agent of “black piedra”
Piedraia hortae (Septate Dematiaceous)
Scalp hair infection, dark brown to black nodules that contain asci (saclike) structures and 8 ascospores
“black piedra” or Piedraia hortae (Septate Dematiaceous)
This is known as skin colonizer, warm loving, and usually found in tropical locations
Malassezia furfur
Also known as Tinea nigra
Hortaea werneckii
Also known as Tinea versicolor
Malassezia furfur
brown to black non scaly macules usually in palms and soles
Hortaea werneckii
Confused or misdiagnosed with malignant melanoma
Hortaea werneckii
Laboratory tests for Hortaea werneckii
- Skin scrapings
- 10-20% KOH
- Hyphal elements w/ budding cells
Trichosporon spp. is also known as?
“white piedra”
Occurs in hair shaft, opportunistic systemic pathogens, associated with immunocompromised diseases
Trichosporon spp.
A Trichosporon spp. that is known to be a human pathogen
Trichosporon beigelii
A Trichosporon spp. that is a systemic disease (meningitis)
T. mucoides
A Trichosporon spp. that is a fatal disease in immunocompromised hosts
T. asahii
Enumerate the important organisms that belong to Superficial mycoses
- Malassezia furfur - yeast
- Piedraia hortae
- Hortaea werneckii
- Trichosporon spp.- yeast
This term is used to describe organisms that are able degrade keratin
Dermatophytes (usually cutaneous mycoses)
This term is used to describe organisms that cannot degrade keratin
Non-dermatophytes (usually mga superficial mycoses)
Utilizes keratin as source of nitrogen
Dermatophytes (Cutaneous mycoses)
Important Genera that belonged to Cutaneous Mycoses
- Trichophyton - hair, skin, nails
- Microsporum - hair and skin
- Epidermophyton - skin and nails
Trichosporon spp. can be grown or cultured in?
Sabouraud Dextrose Agar (SDA)
Other tests that can be performed on Trichosporon spp. are?
- Carbohydrate fermentation
- Potassium nitrate
- Assimilation of sugars
- Urease Test
Most common cause of infection and is anthropophilic
Trichophyton
Caused by Trichophyton and appears as ringworm of the groin, or “jock itch”
Tinea cruris
Caused by Trichophyton and appears as ringworm of the beard
Tinea barbae
Caused by Trichophyton and appears as ringworm of the body
Tinea corporis
Caused by Trichophyton and appears as ringworm on the nail
Tinea unguium
Caused by Trichophyton and appears as ringworm of the feet, or “athlete’s foot”
Tinea pedis
Caused by Trichophyton and appears as ringworm of the scalp and hair
Tinea capitis
Laboratory diagnosis for Trichophyton
Direct Detection Methods such as stain
This stain reveals hyaline septate hyphae or arthroconidia
Calcofluor white or potassium hydroxide
Spores that fill hairshaft
Endothrix
Spores that ensheath hair shaft
Ectothrix
A clinically significant Trichophyton that causes crusty lesions made up of dead epithelia. Has antler hyphae and white and wrinkled colony
T. schoenleinii
Other term for T. schoenleinii
“Tinea favosa”
A clinically significant Trichophyton that is a nail dermatophyte, slow growing and its microconidia appears clavate- or peg-shaped
T. rubrum
IDENTIFY THE TRICHOPHYTON
Colony:
i. white, granular, & fluffy varieties
ii. yellow in younger colonies
T. mentagrophytes
A clinically significant Trichophyton that infects the nails. Its microconidia appear grapelike or teardrop-shaped
T. mentagrophytes
A clinically significant Trichophyton that is a hair dermatophyte and is larger than other dermatophytes.
Its colony appears white, tan to yellow, or rust, suede-like to powdery
T. tonsurans
State the appearance of the microconidia and macroconidia of T. tonsurans
Microconidia- teardrop or club-shaped with flat bottoms
Macroconidia- balloon shaped
IDENTIFY THE TRICHOPHYTON
Colony:
i. white downy - pink granular
ii. Young: reverse yellow
iii. Old: wine/red
T. rubrum
A clinically significant Trichophyton that has glabrous to velvety white colonies
T. verrucosum
IDENTIFY THE TRICHOPHYTON
- Microconidia: large and teardrop-shaped
- Macroconidia: rare, rat-tail
T. verrucosum
A clinically significant Trichophyton that is a hair dermatophyte and is chlamydoconidia (commonly aligned in chains)
T. violaceum
Its macroconidia appear
- echinulate spindle-shaped
- thick-walled
- four or more septa
Microsporum spp.
IDENTIFY THE TRICHOPHYTON
Colony:
i. Port wine to deep violet
ii. Heaped or flat with waxy
iii. Pigment may be lost on subculture
T. violaceum
The appearance of Microsporum spp. microconidia
- club-shaped
- borne on hyphae
Primary cause of tinea capitis. A low-grade superficial lesion, circular, scaly patches of alopecia and “black dot” ringworm
M. audouinii
Aerial hyphae, appear velvety, powdery, glabrous, or cottony, vary in color (whitish-cinnamon brown)
Microsporum spp.
Transmitted through infected hairs on caps, hats, combs
M. audouinii
Appear as rare bizarre-shaped, and or Terminal chlamydospores microscopically
M. audouinii
“Zoophilic“ pathogen of animals. Most common cause of ringworm in dogs
M. canis
Its colony appears
i. cottony white –salmon
ii. velvety aerial mycelium
M. audouinii
IDENTIFY BASED ON THE FF. CHARACTERISTICS
Macroconidia:
- Tapering spiny distal ends
Colony:
- lemon-yellow or yellow-orange fringe
M. canis
M. audouinii positive test
- (+) yellow-green under woods lamp
Infection in hair & skin, free living in the soil (geophilic)
M. gypseum
IDENTIFY
Microscopic appearance:
▪ Fusiform, thick-walled conidia
▪ Spindle-shaped but not as pointed as distal ends of M.canis
M. gypseum
Test for M. canis
- (+) Woods lamp
- calcofluor white or potassium hydroxide
IDENTIFY
Colony:
- powdery surface
- buff or cinnamon color
- undersurface is brownish
M. gypseum
Common cause of tinea cruris and tinea pedis. Susceptible to cold and are slow growers
Epidermophyton spp.
(Epidermophyton floccosum)
IDENTIFY
Microscopic appearance:
- thin-walled macroconidia
- Multiseptate
- Rounded tip
Colony:
- Olive green to khaki
- Dull orange-brown periphery
Epidermophyton spp.
(Epidermophyton floccosum)
Traumatic implantation of foreign objects leading to fungus entry. These agents are commonly found in soil or decaying vegetation
Subcutaneous Mycoses
Chronic fungal infection. It is acquired through traumatic inoculation of organism, and appears as “Papule”
Chromoblastomycosis
This is found at the site of trauma. Enlarges to form warty or tumorlike lesions, resembles cauliflower, and spreads through the lymphatic system
“Papule” in Chromoblastomycosis
Also known as “verrucous dermatitis” or “chromomycosis”
Chromoblastomycosis
Copper-colored, septate cells. Divide by binary fission and resemble “copper pennies”
Sclerotic bodies in Chromoblastomycosis
What are the agents of Chromoblastomycosis
- Cladophialophora carrionii
- Fonsecaea pedrosoi
- Phialophora verrucosa
Sample for lab dx of Chromoblastomycosis
Scrapings from crusted lesion
Appearance of Chromoblastomycosis in 10% potassium hydroxide (KOH)
“muriform cells” – aggregation of dark brown cells
Molecular method used for Chromoblastomycosis
MALDI-TOF MS
Darkly pigmented colonies, Gray – Olive black, Velvety or seudelike are the appearances of this organism when cultivated
Chromoblastomycosis
Microscopically this appears with a sympodial arrangement of conidiophores.
The primary conidia gives rise to secondary conidia, and some conidia may appear similar to others spp. of fungi
Fonsecaea pedrosoi
Microscopically this appears phaeoid, flask-shaped phialides, well developed collarette, and one-celled conidia oval
Phialophora verrucosa
Microscopically this appears with sporulation with long chains of elliptical conidia, erect conidiophores, and fusiform, conidia
Cladophialophora carrionii
Caused by darkly pigmented fungi. Distinguishable by phaeoid fungi
Phaeohyphomycosis
Agents of Phaeohyphomycosis. Enumerate at least three.
- Alternaria spp.
- Bipolaris spp.
- Cladophialophora spp.
- Curvularia spp.
- Exophiala spp.
Phaeohyphomycosis can cause? (Enumerate at least three)
- Phaeohyphomycotic cysts
- Progressive soft tissue infection
- Brain abscess
- Sinusitis
- Pulmonary infection
- Systemic infection
Methods to diagnose Phaeohyphomycosis
- Direct microscopic examination
- Histopathologic examination
- Stains:
✓ Fontana-Masson – detects
melanization
✓ 10% Silver Nitrate
✓ Ammonium hydroxide
This stains fungal elements brown-black in red background
Ammonium hydroxide
Chain of large brown conidia. “Drumstick” appearance
Alternaria spp.
IDENTIFY
- Septate hyphae
- Geniculate conidiophores – bent where conidia are attached
- Conidia are oblong to fusoid
Bipolaris spp.
Appears as shield cells in wet mount
Cladophialophora spp.
IDENTIFY
- Hyaline septate
- Conidiophores are geniculate
- Conidia:
✓ sympodial
✓ golden-brown
✓ central swollen cell
Curvularia spp.
IDENTIFY
- Yeastlike cells
- Produced by annellides
- Conidiophores are cylindrical with tapered tip
- Conidia:
✓ clusters
✓ Round to oval
Exophiala spp.
Chronic infection that arises at the site of inoculation
Characterized by:
- swelling
- exudate
Eumycotic Mycetomas
Molecular method for Eumycotic Mycetomas
Amplification test for fungal DNA in sterile body fluids
Causes mycetomas . Can be caused by bacteria or fungi and occur in tropical or subtropical areas
Eumycotic Mycetomas
Stains used for lab dx of Eumycotic Mycetomas
- Hematoxylin- eosin
- Methenamine silver : appear black
- Fontana- Masson: pigmented hyphae
The teleomorph term for Scedosporium boydii
Pseudoallescheria boydii
Microscopically it appears to produce single oval conidia
Scedosporium boydii
This forms “cleistothecia” containing ascospores and is homothallic
Pseudoallescheria boydii
This is the ability of an organism to go sexual reproduction without a mate
Homothallic
When cultured this is characterized to be a rapid grower, and appears to have white-dark gray colonies on Potato dextrose agar
Scedosporium boydii
Granules of Scedosporium boydii
White mycetoma
Microscopically, it appears unbranched, multiseptated conidiophore. Clusters of single-two-celled conidia, and has conidia at the tip of the conidiophore
Acremonium spp.
The previous name of Acremonium spp.
Fusarium falciforme
Granules of Acremonium spp.
White mycetoma
Septate hyphae and has the most cases of mycetoma
Madurella spp.
IDENTIFY
Microscopic appearance:
✓ Long tapering phialides
✓ Collarettes and sclerotia
✓ Granules: Black Mycetoma
Madurella spp.
IDENTIFY
- Recovered from soil and decaying vegetation
- Most cases are associated with
gardening
- “Rose Handler’s Disease”
Sporothrix schenckii spp. complex
Commonly manifest as
lymphocutaneous sporotrichosis
Sporothrix schenckii spp. complex
Appearance of Sporothrix schenckii spp. complex in direct examination
Small, cigar-shaped yeasts
Dimorphic, examined at 22°C -37°C
Sporothrix schenckii spp. complex
Appearance of Sporothrix schenckii spp. complex in microscopic examination
Rosette pattern conidia