6.2-CHROMOBLASTOMYCOSIS+PHAEOHYPOMYCOSIS+MYCETOMA Flashcards by Dave U.

What are the common etiologic agents of chromoblastomycosis?

Phialophora verrucosa
Fonsecaea pedrosoi
Cladophialophora carrionii
Fonsecaea compacta
Rhinocladiella aquaspersa

Veronica at Pedro carry compact aquaflasks

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A chronic skin and soft tissue infection characterized by musiform fungal structures (sclerotic bodies) in infected tissues

chromoblastomycosis

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What are the key clinical features of chromoblastomycosis?

Formation of verrucous plaques or nodules at the site of inoculation

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chromoblastomycosis Lesions may be ulcerative, leading to the alternate name

verrucous dermatitis/chromomycosis

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How is chromoblastomycosis transmitted?

Puncture wounds or trauma caused by contaminated vegetation

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What is a common characteristic of all chromoblastomycosis-causing fungi?

They are dematiaceous (darkly pigmented)

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What is the macroscopic appearance of chromoblastomycosis-causing fungi?

Colonies are compact, deep brown to black
Develop a velvety, often wrinkled surface

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How do these fungi appear in tissue?

They produce spherical brown cells (4–12 μm in diameter)

These cells are called muriform or sclerotic bodies

They divide by transverse septation

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What is the significance of sclerotic bodies in chromoblastomycosis?

They are diagnostic structures of the infection

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How do cells within superficial crusts or exudates behave?

They may germinate into septate, branching hyphae

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What are the macroscopic characteristics of Phialophora verrucosa colonies?

Rapidly growing
Olive-gray to black in color
Dome-shaped
Wooly or cottony colony

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What are the key microscopic features of Phialophora verrucosa

Septate hyphae with short conidiophores

Flask-shaped or cup-shaped phialides

Collarettes present

Conidia appear compact or joint together

Oval to cylindrical conidia in clusters at the ends of phialides

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What makes Fonsecaea pedrosoi unique as a fungus?

It is a polymorphic genus with multiple forms

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What microscopic structures can be seen in Fonsecaea pedrosoi isolates?

Phialides

Chains of blastoconidia (similar to Cladosporium species)

Sympodial conidiation

Rhinocladiella-type conidiation

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What is the predominant microscopic feature of Fonsecaea pedrosoi?

Dark septate hyphae

Short branching chains of blastoconidia

Sympodial conidia

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How does Fonsecaea pedrosoi appear macroscopically?

Very slow growing

Black-brown, gray-black, or olive-gray colony

Black aerial mycelium

Velvety to cottony texture

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What are the mixed sporulation characteristics of Fonsecaea pedrosoi?

Primary mycosis conidia develop at conidiophore tips

Secondary and tertiary conidia form in a loosely organized conidial head

Branching conidiophores with chains of conidia and flask-shaped phialides

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What is another name for Fonsecaea compacta?

Fonsecaea compactum

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How do the blastoconidia of F. compacta differ from F. pedrosoi?

Blastoconidia are almost spherical
Broad base connecting the conidia
Smaller and more compact than F. pedrosoi

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How do F. compacta and F. pedrosoi differ in morphology?

F. compacta → Subglobose (rounder, more compact)
F. pedrosoi → Ovoid (elongated and larger)

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How does Rhinocladiella aquaspersa produce conidia?

Produces lateral or terminal conidia from a lengthening conidiogenous cell through a sympodial process (tends to be erect).

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What is the shape of Rhinocladiella aquaspersa conidia?

Elliptical to clavate

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What other fungus exhibits an erect sympodial process?

Cladophialophora carrionii

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How do Cladophialophora and Cladosporium species produce conidia?

Through distal (acropetalous) budding in branching chains

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How does the terminal conidium give rise to the next conidium?

Through a budding process

What are the microscopic features of Cladophialophora carrionii?

Elongated, dark conidiophores Long, branching chains of oval blastoconidia Septate hyphae

What are the macroscopic characteristics of Cladophialophora carrionii colonies

Rapidly growing Velvety or cottony texture Olive to black in color Cannot grow at 37°C (saprophytic Cladosporium)

What type of lesion does Cladophialophora carrionii cause?

Verrucous plaques or nodules at the site of inoculation

What lesion is caused by Fonsecaea compacta?

Slow-growing verrucous dermatitis (chromomycosis)

What is the characteristic feature of Fonsecaea pedrosoi lesions?

Cauliflower-like nodules with crusting abscesses

What characteristic feature can be seen on the wart-like surface of Phialophora verrucosa lesions?

Black dots of hemopurulent material

What causes the black dots seen in Fonsecaea pedrosoi infections?

Secondary infections

Is chromoblastomycosis caused by Fonsecaea pedrosoi symptomatic or asymptomatic?

Usually asymptomatic, but complications can arise due to secondary infections

What secondary complications can develop in chromoblastomycosis?

Elephantiasis (Wuchereria bancrofti) Bacterial superinfection Carcinomatous degeneration

Which body part is most commonly affected by Fonsecaea pedrosoi infections?

Lower extremities

Does Phialophora verrucosa chromoblastomycosis spread to other body parts?

Dissemination is very rare

What causes satellite lesions in Fonsecaea pedrosoi infections?

Local lymphatic spread or autoinoculation

Is Cladophialophora carrionii chromoblastomycosis transmissible between people?

No, it is not transmissible

What histological feature characterizes Fonsecaea compacta lesions?

Granulomatous inflammation with dark sclerotic bodies

How do sclerotic bodies of Phialophora verrucosa appear histologically?

Dark, round, thick-walled fungal cells within leukocytes or giant cells

What specimens are used for diagnosing chromoblastomycosis?

Scrapings or biopsies from lesions

What is the purpose of using 10% KOH in the diagnosis of chromoblastomycosis?

To dissolve keratin and allow visualization of dark, spherical fungal cells

What is a diagnostic microscopic finding in chromoblastomycosis?

Detection of sclerotic bodies (copper-colored septate cells)

What do tissue sections reveal in chromoblastomycosis?

Granulomas and extensive hyperplasia of dermal tissue

What are the recommended culture media for chromoblastomycosis?

Inhibitory mold agar Sabouraud’s agar with antibiotics

What is the therapy of choice for small chromoblastomycosis lesions?

Surgical excision with wide margins

What chemotherapy agents are effective for larger chromoblastomycosis lesions?

Flucytosine or itraconazole

What additional treatment method can be beneficial for chromoblastomycosis?

Application of local heat

What is a common issue in the treatment of chromoblastomycosis?

Relapse is common

How can chromoblastomycosis be prevented?

Wearing shoes and protecting the legs

In which climate is chromoblastomycosis most commonly found?

Tropical regions

Is chromoblastomycosis communicable between people?

No, it is not communicable

Where do the fungi that cause chromoblastomycosis naturally occur?

Saprophytic in vegetation and soil

Which population is most at risk for chromoblastomycosis?

Barefoot agrarian workers

How is chromoblastomycosis usually acquired?

Traumatic introduction of the fungus into the skin

What are the fungi that can cause phaeohyphomycosis?

Exophiala jeanselmei Wangiella dermatitidis Phialophora richardsiae Bipolaris spp. Curvularia spp. Alternaria spp. Drechslera spp. Exserohilum spp. wearin my Exotic JEANS to the DERMA coz am RICH

Infections characterized by darkly pigmented septate hyphae in tissue

phaeohyphomycosis

What are the clinical forms of phaeohyphomycosis?

Solitary encapsulated cysts in subcutaneous tissue Sinusitis Brain abscesses

How many species of dematiaceous molds have been associated with phaeohyphomycosis?

Over 100 species

What type of fungi cause phaeohyphomycosis?

Exogenous molds that normally exist in nature

What are the most common causes of subcutaneous phaeohyphomycosis?

Exophiala jeanselmei Phialophora richardsiae Bipolaris spicifera Wangiella dermatitidis

What types of mycoses can phaeohyphomycosis cause?

Cutaneous and systemic mycoses

What is the leading cause of cerebral phaeohyphomycosis?

Cladophialophora bantiana

How do hyphae appear in tissue during phaeohyphomycosis?

Large (5–10 μm in diameter), often distorted, and may be accompanied by yeast cells

How is phaeohyphomycosis diagnosed?

Specimens are cultured on routine fungal media to identify the etiologic agent

What are the drugs of choice for phaeohyphomycosis?

Itraconazole Flucytosine

How are brain abscesses caused by phaeohyphomycosis managed?

Amphotericin B and surgery

How does Exophiala jeanselmei appear in culture?

Moderately fast-growing, gray to black, moist, yeast-like colony with black woolly mycelium

At what temperature does Exophiala jeanselmei grow?

37°C but not at 40°C

How does Exophiala jeanselmei appear microscopically?

Pale brown conidiophores forming cylindrical annellides; one-celled hyaline conidia gathered at tips of annellides

How does Wangiella dermatitidis appear in culture?

Rapidly growing, moist, shiny, yeast colony that later develops black, olive, velvety mycelium

At what temperature does Wangiella dermatitidis grow?

Well at 40°C, unlike other dematiaceous fungi

How does Wangiella dermatitidis appear microscopically?

Dark budding yeast that later develops tube-like phialides lacking colarettes and annellations; balls of one-celled hyaline conidia at phialide openings

What is a distinguishing microscopic feature of Phialophora richardsiae?

Phialides with distinct flattened or saucer-like collarettes

How are conidia produced in Phialophora richardsiae?

Produced endogenously and occur in clusters at the tip of the phialide

How do Bipolaris spp. colonies appear in culture?

Gray-green to dark brown, slightly powdery

What is the term used to describe the bent structure in Bipolaris spp.?

Geniculate (bent)

What type of hyphae do Bipolaris spp. have?

Dematiaceous and septate

What characteristic shape do Bipolaris spp. conidiophores exhibit?

Bent (geniculate) at locations where conidia are attached

How are conidia of Bipolaris spp. arranged?

Sympodially, oblong to fusoid

What is a key feature of Bipolaris spp. conidia?

Hilum slightly protrudes; germ tubes form at one or both ends, parallel to the long axis of the conidium

What conditions are required for germ tube formation in Bipolaris spp.?

25°C for up to 24 hours

How do Curvularia spp. colonies appear in culture?

Fluffy or downy, olive-gray to black, rapid growth

What type of hyphae do Curvularia spp. have?

Dematiaceous and septate

What characteristic structure do Curvularia spp. conidiophores exhibit?

Geniculate (bent at conidia attachment sites)

How are Curvularia spp. conidia arranged?

Sympodially

What is a distinguishing feature of Curvularia spp. conidia?

Golden brown, multicelled, curved, with a central swollen cell

How do the end cells of Curvularia spp. conidia compare to the swollen cell?

Lighter in color than the swollen cell

Why is Curvularia spp. named as such?

Due to its curved conidia

How do Alternaria spp. colonies appear in culture?

Rapidly growing, fluffy, gray to gray-brown or gray-green

What type of hyphae do Alternaria spp. have?

Septate, golden brown pigmented

What are the characteristics of Alternaria spp. conidiophores?

Simple, sometimes branched

How are Alternaria spp. conidia arranged?

In chains, large, brown, resembling a drumstick

What type of septation do Alternaria spp. conidia have?

Both horizontal and longitudinal septa

What makes observation of Alternaria spp. conidia difficult?

Chains of conidia may become dislodged

What type of hyphae do Drechslera spp. have?

Septate, darkly pigmented

What characteristic shape do Drechslera spp. conidiophores exhibit?

Geniculate (bent at conidia attachment sites)

How are Drechslera spp. conidia arranged?

Sympodially

What is a distinguishing feature of Drechslera spp. conidia?

Sporulation is sparse and not commonly seen

How can Drechslera spp. be differentiated from Bipolaris spp.?

Using the germ tube test

How do Drechslera spp. germ tubes grow in relation to the conidium?

Perpendicular to the long axis of the conidium

How do Bipolaris spp. germ tubes grow in relation to the conidium?

Parallel to the longitudinal axis of the conidium

What type of hyphae do Exserohilum spp. have?

Septate and dematiaceous

What characteristic shape do Exserohilum spp. conidiophores exhibit?

Geniculate (bent at conidia attachment sites)

How are Exserohilum spp. conidia arranged?

Sympodially

What is the shape of Exserohilum spp. conidia?

Elongate, ellipsoid to fusoid

What is a unique feature of Exserohilum spp. conidia?

Prominent hilum that is truncated and protruding

What type of septation do Exserohilum spp. conidia have?

Multicellular with perpendicular septa

How many septa do Exserohilum spp. conidia usually contain?

5 to 9 septa

What are the two types of Mycetoma?

Actinomycetoma (bacterial) & Eumycetoma (fungal)

What is another name for Eumycetoma?

Madura foot / Maduramycosis

What type of fungi cause Mycetoma?

Hyaline & Dematiaceous fungi

What is the mode of transmission for Mycetoma?

Traumatic injury with contaminated soil-laden materials (splinter, thorn, pricks)

What is the characteristic appearance of Mycetoma?

Painless subcutaneous mass with multiple sinuses draining pus and granules

Which areas are most affected by Mycetoma?

Feet & hands

Which fungi produce white granules?

Pseudallescheria boydii, Acremonium falciforme

Which fungi produce black granules?

Madurella grisea, Exophiala jeanselmei, Curvularia spp.

Which fungus produces red to black granules?

Madurella mycetomatis

Which fungus produces hard granules?

Madurella mycetomatis

What type of granules do all other fungi produce?

Soft granules

What is a unique feature of Pseudallescheria boydii?

Self-fertile (homothallic) & produces ascospores in culture

What is a major clinical significance of Pseudallescheria boydii?

Resistant to amphotericin B

What color granules does Pseudallescheria boydii produce?

White granules

How do Pseudallescheria boydii colonies appear?

Cottony, white to gray, fluffy; later brownish-gray

How does Pseudallescheria boydii appear on Potato Dextrose Agar?

Gray appearance

What is the reverse color of Pseudallescheria boydii colonies?

Tan to brown or black

What is the teleomorph structure of Pseudallescheria boydii?

Sac-like cleistothecia containing asci & ascospores

What is the anamorphic (asexual) form of Pseudallescheria boydii?

Golden-brown, elliptoid, single-celled conidia on conidiophores

What is the less common stage of Pseudallescheria boydii?

Graphium stage (clusters of conidiophores with conidia at ends, aka coremia)

What type of hyphae does Acremonium falciforme develop?

Hyaline hyphae

What type of conidiophores does Acremonium falciforme have?

Simple, unbranched, erect

How are Acremonium falciforme conidia arranged?

Loosely or in gelatinous masses at conidiophore tip (mucoid clusters)

What other structures may Acremonium falciforme produce?

Intercalary & terminal chlamydoconidia

How do Madurella mycetomatis colonies appear?

White (early), then olive-brown with brown diffusible pigment

Which fungus does Madurella mycetomatis resemble?

Piedraia hortae

Why is there no conidial description for Madurella mycetomatis?

Hyphae are sterile

What is the primary method for Mycetoma diagnosis?

Culture on standard fungal media (SDA), takes ≥ 4 weeks

What is examined from pus or biopsy material in Mycetoma diagnosis?

Granules (color, texture, size, hyaline/pigmented hyphae)

What bacterial infections often superinfect Mycetoma?

Staphylococci & Streptococci

What is the general management for Mycetoma?

Surgical debridement/excision + chemotherapy

What is the treatment for Pseudallescheria boydii?

Topical nystatin or miconazole

What is the treatment for Madurella spp. infections?

Itraconazole, ketoconazole, or amphotericin B

What is the treatment for Exophiala jeanselmei?

Flucytosine

6.2-CHROMOBLASTOMYCOSIS+PHAEOHYPOMYCOSIS+MYCETOMA Flashcards

(143 cards)