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Mycology > Subcutaneous Mycoses > Flashcards

Subcutaneous Mycoses Flashcards

1
Q

Subcutaneous Mycoses

A

Due to traumatic implantation (skin trauma)
Agents are ALL soil saprophytes
More significant

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2
Q

Most Common Subcutaneous Infections

A

Sporotrichosis
Mycetoma
Chromomycosis

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3
Q

Sporotrichosis

A

Agent: Sporothrix Schenckii
Growth sources: Roses and Sphagnum Moss
Manifestations:
Cutaneous - small local papules (arms/legs)
Lymphocutaneous - nodules in lymphatics are enlarged and discolored (buboes)
Bronchitis, TB -like - rare cases
Osteoarticular - most common extracutaneous disorder
Dioagnosis: Sporotrochin Skin Test

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4
Q

Microscopic Characteristics of Sporothriz schencki

A

Conidiophores arise from thin septate hyphae TAPERED towards end, and
Conidia are formed in clusters with their arrangement to a FLOWER “DAISIES”.
CIGAR SHAPED

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5
Q

A chronic suppurative infection of subcutaneous tissue and contagious bone

A

Mycetoma

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6
Q

Most common Site of infection

A

FEET

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7
Q

Mycetoma

A

Other name: Maduromycosis/Madura Foot Infection

Agents:
Sexual Form - P. boydii
Asexual Form - S. apiospermum & S. prolificans
E. jeanselmei, M. grisea, M. mycetomatis

Manifestation:
Discharge of viscous purulent fluid/serosanguinous fluid with GRANULES
Spread to bones, causing deformity

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8
Q

Hallmark of Mycetoma

A

Fluids Granules/Grains

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9
Q

Microscopic Morphology: S. apoiospermum

A

Single celled, TRUNCATE BASES, simple or branched conidiophores, annelation - RING LIKE SCARS ON APEX

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10
Q

Microscopic Morphology: S. prolificans

A

Basally swollen , FLASKED SHAPED ANNELIDES

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11
Q

This organism is inhibited by cycloheximide

A

P. boydii

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12
Q

True or False.
S. apiospermum - does not grow in cycloheximide
S. prolificans - grow with cycloheximide

A

False.
S. apiospermum - GROW in cycloheximide
S. prolificans - DOESN’T GROW with cycloheximide

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13
Q

Microscopic appearance of P. boydii

A

Sepatated Hyphae are hyaline
Conidiophores with annelides
LARGE BROWN CLEISTIOTHECIA (sac-like structure with asci and ascospores)

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14
Q

Mycetoma - Exophiala jeanselmei

A

Macroscopic: Greenish gray to black, mucoid, smooth with tufts of aerial mycelium and becoming sude-like texture.

Microscopic: Bradly ellipsoidal cells, inflated, smooth thin walled with inconspicuous basal scars.

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15
Q

Mycetoma - Madurella grisea

A

Macroscopic: Leathery folded with radial grooves and light brown greyish surface mycelium.

Microscopic:
Septate Hyphae - branched and dark
Grains: Black, deeply pigmented periphery

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16
Q

Mycetoma - Medurella mycetomatis

A

Macroscopic - Brown diffusible pigment

Microscopic - Conidia; Flasked-shaped PHIALIDES (1st), Pyriform conidia wit truncated bases (2nd)

17
Q

Chromoblastomycosis

A

Agent: Chlodosporium, Phiolophora, Fonsecaea
Characteristic: Slowly progressive GRANULOMATOUS infection; “Wart-like lesions”
Colonial appearance: Darkly pigmented colonies, heaped-up, VELVETY appearance; Reverse - Jet black

18
Q

A slowly progressive GRANULOMATOUS lesions by dematiaceous fungi.

A

Chromomycosis/Chromoblastomycosis

19
Q

Three Types of Sporulation in Chromomycosis

A

Chladosporium Type - shield shape
Rhinocladiella Type - Single at tend and side of conidiophore
Phiolophora Type - Conidia extrude from flasked-shaped phialides

20
Q

Fonseceae spp. to cause Chromoblastomycosis

A

F. pedrosoi (most common)
F. monophora
F. compacta (morphological variant of F. pedrosoi)

21
Q

Fonseceae spp. Characteristics

A

Indistinct MELANISED conidiophores with BLUNT, SCATTERED DENTICLES
Pale olivaceous
Formation of Sclerotic Bodies

22
Q

Most common cause of Chromoblastomycosis

A

F. pedrosoi

23
Q

A specific structure formed by Fonseceae spp. in single or clustered, round, tick walled, dark brown to black organism that multiply by planate division

A

Sclerotic Bodies

24
Q

True or False.
F. Pedrosoi - Long Conidial chains with Short denticles. F. monophora are shorter conidial chains and denticles are slightly longer.

A

1st Statment: True

2ns Statement: False. F. monophora have slighlty longer chains with slightly shorter denticle

25
Q

Most common indoor and outdoor Molds

A

C. carrionii

26
Q

C. carrionii

A

Macroscopic: Olivaceous- black colony
Microscopic: Branching olivaceous green, elongate conidiophores, smooth walled conidia; Bulboes phialides

27
Q

C. bandium

A

Macroscopic: Olivaceous grey colony, suede like
Microscopic: Chains of undifferentiated conidiophores, Pale brown, Ellipsoid to Oblong-Ellipsoid

28
Q

Difference of C. bandium to C. carrionii

A
  1. Absence of conidia with distinct pigmented Hila
  2. No shield cell characteristic
  3. Grows at 42C
29
Q

A NEUROTROPIC fungus involving CNS and associated with Keratitis, Otitis, Pneumonia, and Endocarditis.

A

Wingellia dermatitidis

30
Q

W. dermatitidis

A

Macroscopic:
Black to Olive black
Budding yeasts and Hyphae
Moist, Shiny, Velvety at Periphery

Microscopic: FLASK SHAPED TO CYLINDRICAL W/O COLLARETES
Septate Brown hyphae
Yeast cells are present
Brown Phialides, branched,

31
Q

P. verrucosa

A

Microscopic: FUNNEL/CUP SHAPED DARKLY PIGMENTED COLLARETTES

Macroscopic: Dome Shaped,

32
Q

Regarding ringworm and the dermatophytes, which one of the following is most
accurate?
(A) The dermatophytes are molds and are not thermally dimorphic.
(B) The drug of choice for the treatment of ringworm lesions is amphotericin B.
(C) The purpose of the KOH prep is to observe fungal antigens within infected cells.
(D) The dermatophytid reaction refers to the necrotic area typically seen in the center of ringworm lesions.
(E) The principal reservoir of dermatophytes in the genus Trichophyton is domestic animals such as dogs and cats.

A

A The dermatophytes are molds and are not thermally dimorphic.

33
Q

Regarding sporotrichosis and Sporothrix schenckii, which one of the following is most accurate?
(A) The main reservoir of Sporothrix is dog feces.
(B) Laboratory diagnosis involves seeing a nonseptate mold in an aspirate of the lesion.
(C) Sporothrix is often acquired by penetrating wounds sustained while gardening.
(D) The treatment of choice for sporotrichosis is surgical removal of the lesion because there is no effective drug.
(E) Disease occurs primarily in patients who are deficient in the late-acting
complement components.

A

C Sporothrix is often acquired by penetrating wounds sustained while gardening.

34
Q

Your patient is a 65-year-old woman with a 2-cm ulcerated lesion on the palm of her hand that has been gradually getting bigger during the past month. The lesion is only slightly tender and is not red, hot, or painful. A careful history reveals that
she was making holly wreaths for use at Christmas. (Holly leaves have sharp points.) She is afebrile and otherwise well. An aspirate of the lesion was
obtained. Which one of the following would best support a diagnosis of sporotrichosis?
(A) A culture on blood agar at 25°C revealed white, beta-hemolytic colonies.
(B) A methenamine silver stain examined in the light microscope revealed budding yeasts.
(C) A KOH preparation examined in the light microscope revealed septate
hyphae.
(D) A culture on Sabouraud’s agar at 37°C revealed a brownish mycelium with
green spores.
(E) An unstained sample examined in the dark field microscope revealed nonseptate hyphae.

A

(B) A methenamine silver stain examined in the light microscope revealed budding yeasts.

35
Q

A landscaper noticed a hard, unmovable lump under
the skin of his index finger but decided to ignore it. A
month later, the lump ulcerated to present a necrotic
appearance, and two more lesions developed further
up the wrist and forearm. A histologic stain of material from deep in the lesions showed elongated yeast
cells resembling cigars. What disease is suspected?
a. Mycetoma
b. Sporotrichosis
c. Chromoblastomycosis
d. Blastomycosis

A

b. Sporotrichosis

36
Q

A mold that produces colonies with a dark brown,
green-black, or black appearance of both the
surface and reverse side is classified as a:
A. Dematiaceous mold
B. Dermatophyte
C. Hyaline mold
D. Dimorphic fungus

A

A. Dematiaceous mold

Mycology (7 decks)

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