6.2-CHROMOBLASTOMYCOSIS+PHAEOHYPOMYCOSIS+MYCETOMA Flashcards
What are the common etiologic agents of chromoblastomycosis?
Phialophora verrucosa
Fonsecaea pedrosoi
Cladophialophora carrionii
Fonsecaea compacta
Rhinocladiella aquaspersa
Veronica at Pedro carry compact aquaflasks
A chronic skin and soft tissue infection characterized by musiform fungal structures (sclerotic bodies) in infected tissues
chromoblastomycosis
What are the key clinical features of chromoblastomycosis?
Formation of verrucous plaques or nodules at the site of inoculation
chromoblastomycosis Lesions may be ulcerative, leading to the alternate name
verrucous dermatitis/chromomycosis
How is chromoblastomycosis transmitted?
Puncture wounds or trauma caused by contaminated vegetation
What is a common characteristic of all chromoblastomycosis-causing fungi?
They are dematiaceous (darkly pigmented)
What is the macroscopic appearance of chromoblastomycosis-causing fungi?
Colonies are compact, deep brown to black
Develop a velvety, often wrinkled surface
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
What is the significance of sclerotic bodies in chromoblastomycosis?
They are diagnostic structures of the infection
How do cells within superficial crusts or exudates behave?
They may germinate into septate, branching hyphae
What are the macroscopic characteristics of Phialophora verrucosa colonies?
Rapidly growing
Olive-gray to black in color
Dome-shaped
Wooly or cottony colony
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
What makes Fonsecaea pedrosoi unique as a fungus?
It is a polymorphic genus with multiple forms
What microscopic structures can be seen in Fonsecaea pedrosoi isolates?
Phialides
Chains of blastoconidia (similar to Cladosporium species)
Sympodial conidiation
Rhinocladiella-type conidiation
What is the predominant microscopic feature of Fonsecaea pedrosoi?
Dark septate hyphae
Short branching chains of blastoconidia
Sympodial conidia
How does Fonsecaea pedrosoi appear macroscopically?
Very slow growing
Black-brown, gray-black, or olive-gray colony
Black aerial mycelium
Velvety to cottony texture
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
What is another name for Fonsecaea compacta?
Fonsecaea compactum
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
How do F. compacta and F. pedrosoi differ in morphology?
F. compacta → Subglobose (rounder, more compact)
F. pedrosoi → Ovoid (elongated and larger)
How does Rhinocladiella aquaspersa produce conidia?
Produces lateral or terminal conidia from a lengthening conidiogenous cell through a sympodial process (tends to be erect).
What is the shape of Rhinocladiella aquaspersa conidia?
Elliptical to clavate
What other fungus exhibits an erect sympodial process?
Cladophialophora carrionii
How do Cladophialophora and Cladosporium species produce conidia?
Through distal (acropetalous) budding in branching chains
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
