MYCO & VIRULOGY L2 (Prelim- Subcutaneous & Cutaneous) Flashcards
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1
Q
Infects outermost layer of skin or hair
A
Superficial mycoses
2
Q
Causes patchy lesions/ scaling, dandruff, and prevalent during warm weather
A
Malassezia furfur
3
Q
Appearance of an outer ring of a progressing infection
A
Malassezia furfur
4
Q
Common sites of Malassezia furfur
A
- face
- chest
- trunk
- abdomen
5
Q
Appearance of Malassezia furfur under KOH
A
- “spaghetti and meatballs fungus”
- budding yeasts
6
Q
Positive for Malassezia furfur in wood lamp
A
Yellow fluorescence
7
Q
Causative agent of “black piedra”
A
Piedraia hortae (Septate Dematiaceous)
8
Q
Scalp hair infection, dark brown to black nodules that contain asci (saclike) structures and 8 ascospores
A
“black piedra” or Piedraia hortae (Septate Dematiaceous)
9
Q
This is known as skin colonizer, warm loving, and usually found in tropical locations
A
Malassezia furfur
10
Q
Also known as Tinea nigra
A
Hortaea werneckii
11
Q
Also known as Tinea versicolor
A
Malassezia furfur
12
Q
brown to black non scaly macules usually in palms and soles
A
Hortaea werneckii
13
Q
Confused or misdiagnosed with malignant melanoma
A
Hortaea werneckii
14
Q
Laboratory tests for Hortaea werneckii
A
- Skin scrapings
- 10-20% KOH
- Hyphal elements w/ budding cells
15
Q
Trichosporon spp. is also known as?
A
“white piedra”
16
Q
Occurs in hair shaft, opportunistic systemic pathogens, associated with immunocompromised diseases
A
Trichosporon spp.
17
Q
A Trichosporon spp. that is known to be a human pathogen
A
Trichosporon beigelii
18
Q
A Trichosporon spp. that is a systemic disease (meningitis)
A
T. mucoides
19
Q
A Trichosporon spp. that is a fatal disease in immunocompromised hosts
A
T. asahii
20
Q
Enumerate the important organisms that belong to Superficial mycoses
A
- Malassezia furfur - yeast
- Piedraia hortae
- Hortaea werneckii
- Trichosporon spp.- yeast
21
Q
This term is used to describe organisms that are able degrade keratin
A
Dermatophytes (usually cutaneous mycoses)
22
Q
This term is used to describe organisms that cannot degrade keratin
A
Non-dermatophytes (usually mga superficial mycoses)
23
Q
Utilizes keratin as source of nitrogen
A
Dermatophytes (Cutaneous mycoses)
24
Q
Important Genera that belonged to Cutaneous Mycoses
A
- Trichophyton - hair, skin, nails
- Microsporum - hair and skin
- Epidermophyton - skin and nails
25
**Trichosporon** **spp**. can be grown or cultured in?
Sabouraud Dextrose Agar (SDA)
26
Other tests that can be performed on Trichosporon spp. are?
- Carbohydrate fermentation
- Potassium nitrate
- Assimilation of sugars
- Urease Test
27
**Most common cause** of infection and is **anthropophilic**
Trichophyton
28
Caused by Trichophyton and appears as ringworm of the **groin, or “jock itch”**
Tinea cruris
29
Caused by Trichophyton and appears as ringworm of the **beard**
Tinea barbae
30
Caused by Trichophyton and appears as ringworm of the **body**
Tinea corporis
31
Caused by Trichophyton and appears as ringworm on the **nail**
Tinea unguium
32
Caused by Trichophyton and appears as ringworm of the **feet**, or ***“athlete’s foot”***
Tinea pedis
33
Caused by Trichophyton and appears as ringworm of the **scalp** and **hair**
Tinea capitis
34
Laboratory diagnosis for Trichophyton
Direct Detection Methods such as stain
35
This stain reveals **hyaline** septate hyphae or **arthroconidia**
Calcofluor white or potassium hydroxide
36
Spores that fill hairshaft
Endothrix
37
Spores that ensheath hair shaft
Ectothrix
38
A clinically significant Trichophyton that causes **crusty lesions** made up of dead epithelia. Has antler hyphae and white and wrinkled colony
T. schoenleinii
38
Other term for T. schoenleinii
“Tinea favosa”
39
A clinically significant Trichophyton that is a nail dermatophyte, **slow** **growing** and its microconidia appears **clavate- or peg-shaped**
T. rubrum
39
IDENTIFY THE TRICHOPHYTON
Colony:
i. white, granular, & fluffy varieties
ii. **yellow in younger colonies**
T. mentagrophytes
39
A clinically significant Trichophyton that infects the nails. Its microconidia appear **grapelike** or **teardrop-shaped**
T. mentagrophytes
40
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
41
State the appearance of the microconidia and macroconidia of T. tonsurans
Microconidia- teardrop or club-shaped with flat bottoms
Macroconidia- balloon shaped
42
IDENTIFY THE TRICHOPHYTON
Colony:
i. white downy - pink granular
ii. Young: reverse yellow
iii. Old: wine/red
T. rubrum
43
A clinically significant Trichophyton that has **glabrous** to **velvety white colonies**
T. verrucosum
43
IDENTIFY THE TRICHOPHYTON
- Microconidia: large and teardrop-shaped
- Macroconidia: ***rare, rat-tail***
T. verrucosum
43
A clinically significant Trichophyton that is a hair dermatophyte and is **chlamydoconidia** (commonly aligned in chains)
T. violaceum
44
Its macroconidia appear
- **echinulate** spindle-shaped
- thick-walled
- **four or more septa**
Microsporum spp.
44
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
45
The appearance of Microsporum spp. **microconidia**
- club-shaped
- borne on hyphae
46
***Primary cause of tinea capitis***. A low-grade superficial lesion, circular, scaly patches of alopecia and ***“black dot” ringworm***
M. audouinii
47
**Aerial hyphae,** appear velvety, powdery, glabrous, or cottony, vary in color (whitish-cinnamon brown)
Microsporum spp.
48
Transmitted through infected **hairs on caps, hats, combs**
M. audouinii
49
Appear as **rare bizarre-shaped**, and or **Terminal** **chlamydospores** microscopically
M. audouinii
50
“Zoophilic“ pathogen of animals. Most common cause of ringworm in dogs
M. canis
50
Its colony appears
i. cottony white –salmon
ii. velvety aerial mycelium
M. audouinii
50
IDENTIFY BASED ON THE FF. CHARACTERISTICS
Macroconidia:
- **Tapering spiny distal ends**
Colony:
- **lemon-yellow** or **yellow-orange fringe**
M. canis
50
M. audouinii positive test
- (+) **yellow-green** under woods lamp
51
Infection in hair & skin, **free living in the soil** (geophilic)
M. gypseum
51
IDENTIFY
Microscopic appearance:
▪ Fusiform, thick-walled conidia
▪ Spindle-shaped but not as pointed as distal ends of M.canis
M. gypseum
51
Test for M. canis
- (+) Woods lamp
- calcofluor white or potassium hydroxide
51
IDENTIFY
Colony:
- powdery surface
- buff or cinnamon color
- undersurface is brownish
M. gypseum
52
Common cause of tinea cruris and tinea pedis. Susceptible to cold and are slow growers
Epidermophyton spp.
(Epidermophyton floccosum)
53
IDENTIFY
Microscopic appearance:
- thin-walled macroconidia
- Multiseptate
- **Rounded tip**
Colony:
- **Olive green to khaki**
- **Dull orange-brown** periphery
Epidermophyton spp.
(Epidermophyton floccosum)
54
Traumatic implantation of foreign objects leading to fungus entry. These agents are commonly found in **soil** or **decaying vegetation**
Subcutaneous Mycoses
55
Chronic fungal infection. It is acquired through traumatic inoculation of organism, and appears as “**Papule**”
Chromoblastomycosis
55
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
56
Also known as “verrucous dermatitis” or “chromomycosis”
Chromoblastomycosis
57
Copper-colored, septate cells. Divide by binary fission and resemble “copper pennies”
Sclerotic bodies in Chromoblastomycosis
58
What are the agents of Chromoblastomycosis
- Cladophialophora carrionii
- Fonsecaea pedrosoi
- Phialophora verrucosa
58
Sample for lab dx of Chromoblastomycosis
Scrapings from crusted lesion
59
Appearance of Chromoblastomycosis in 10% potassium hydroxide (KOH)
“muriform cells” – aggregation of dark brown cells
60
Molecular method used for Chromoblastomycosis
MALDI-TOF MS
60
Darkly pigmented colonies, Gray – Olive black, Velvety or seudelike are the appearances of this organism when cultivated
Chromoblastomycosis
61
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
61
Microscopically this appears phaeoid, flask-shaped phialides, well developed collarette, and one-celled conidia oval
Phialophora verrucosa
62
Microscopically this appears with sporulation with long chains of elliptical conidia, erect conidiophores, and fusiform, conidia
Cladophialophora carrionii
63
Caused by darkly pigmented fungi. Distinguishable by phaeoid fungi
Phaeohyphomycosis
63
Agents of Phaeohyphomycosis. Enumerate at least three.
- Alternaria spp.
- Bipolaris spp.
- Cladophialophora spp.
- Curvularia spp.
- Exophiala spp.
64
Phaeohyphomycosis can cause? (Enumerate at least three)
- Phaeohyphomycotic cysts
- Progressive soft tissue infection
- Brain abscess
- Sinusitis
- Pulmonary infection
- Systemic infection
65
Methods to diagnose Phaeohyphomycosis
1. Direct microscopic examination
2. Histopathologic examination
3. Stains:
✓ Fontana-Masson – detects
melanization
✓ 10% Silver Nitrate
✓ Ammonium hydroxide
65
This stains fungal elements brown-black in red background
Ammonium hydroxide
66
Chain of large brown conidia. “Drumstick” appearance
Alternaria spp.
67
IDENTIFY
- Septate hyphae
- Geniculate conidiophores – bent where conidia are attached
- Conidia are oblong to fusoid
Bipolaris spp.
68
Appears as ***shield cells*** in wet mount
Cladophialophora spp.
69
IDENTIFY
- Hyaline septate
- Conidiophores are geniculate
- Conidia:
✓ sympodial
✓ golden-brown
✓ central swollen cell
Curvularia spp.
70
IDENTIFY
- Yeastlike cells
- Produced by annellides
- Conidiophores are cylindrical with tapered tip
- Conidia:
✓ clusters
✓ Round to oval
Exophiala spp.
70
Chronic infection that arises at the site of inoculation
Characterized by:
- swelling
- exudate
Eumycotic Mycetomas
71
Molecular method for Eumycotic Mycetomas
Amplification test for fungal DNA in sterile body fluids
71
Causes **mycetomas** . Can be caused by bacteria or fungi and occur in tropical or subtropical areas
Eumycotic Mycetomas
72
Stains used for lab dx of Eumycotic Mycetomas
1. Hematoxylin- eosin
2. Methenamine silver : appear black
3. Fontana- Masson: pigmented hyphae
73
The teleomorph term for Scedosporium boydii
Pseudoallescheria boydii
73
Microscopically it appears to produce single oval conidia
Scedosporium boydii
73
This forms “cleistothecia” containing ascospores and is homothallic
Pseudoallescheria boydii
73
This is the ability of an organism to go sexual reproduction without a mate
Homothallic
74
When cultured this is characterized to be a rapid grower, and appears to have white-dark gray colonies on Potato dextrose agar
Scedosporium boydii
75
Granules of Scedosporium boydii
White mycetoma
76
Microscopically, it appears unbranched, multiseptated conidiophore. Clusters of single-two-celled conidia, and has conidia at the tip of the conidiophore
Acremonium spp.
77
The previous name of Acremonium spp.
Fusarium falciforme
78
Granules of Acremonium spp.
White mycetoma
79
Septate hyphae and has the most cases of mycetoma
Madurella spp.
80
IDENTIFY
Microscopic appearance:
✓ Long tapering phialides
✓ Collarettes and sclerotia
✓ Granules: Black Mycetoma
Madurella spp.
81
IDENTIFY
- Recovered from soil and decaying vegetation
- Most cases are associated with
gardening
- “Rose Handler’s Disease”
Sporothrix schenckii spp. complex
82
Commonly manifest as
lymphocutaneous sporotrichosis
Sporothrix schenckii spp. complex
83
Appearance of Sporothrix schenckii spp. complex in direct examination
Small, cigar-shaped yeasts
83
Dimorphic, examined at 22°C -37°C
Sporothrix schenckii spp. complex
83
Appearance of Sporothrix schenckii spp. complex in microscopic examination
Rosette pattern conidia
