Subcutaneous Mycoses Flashcards by Kyra Catedral

are introduced by traumatic injury of the skin or subcutaneous tissue with contaminated material.

Subcutaneous Mycoses

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exogenous fungi that normally reside in nature, and most are associated with soil or vegetation.

Subcutaneous Mycoses

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• are caused by a heterogeneous group of fungi that infect the skin, subcutaneous tissues, and in some cases the underlying tissues and organs.

Subcutaneous Mycoses

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7 subcutaneous mycoses

Sporothricosis
Chromoblastomycosis
Phaeyohyphomycosis
Eumycetoma
Subcutaneous zygomycosis - (Entomophthoromycosis)
Rhinosporidiosis
Lobonycosis

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Sporotrichosis

• Distribution: Worldwide (_____)

endemic in Brazil, Peru, Mexico (_____)

limited to Japan, Korea, China (_____)

South Africa; a cosmopolitan disease - warm, tropical, temperate regions

S. schenckii

S. brasiliensis - cats

S. globosa

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• Secondary spread to articular surfaces, bone and muscle (rare) and the infection may also occasionally involve the central nervous system, lungs or genitourinary tract; immunosuppressed patients

Sporotrichosis

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Sporotrichosis

• Major Etiological Agents:(3) - dimorphic fungi (one complex species)

Sporothrix schenckii,
S. brasiliensis, &
S. globosa

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Sporotrichosis

showing typical elevated subcutaneous nodules developing along the regional lymphatics of the forearm.

showing more advanced, ulcerating lesions developing along the lymph system of the forearm.

Lymphocutaneous sporotrichosis

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sporotrichosis of the **wrist and hand, **

looking remarkably similar to
chromoblastomycosis.

Fixed cutaneous verrucous-type

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Sporothrix schenckii complex
A dimorphic fungus that lives throughout the world in soil and on plant matter such as sphagnum moss, rose bushes, and hay.

A species complex of five distinct species: (5)

Infection: An occupational risk for….

Prevention: Minimize accidental inoculation. Use of fungicides to treat wood. Treat infected animals.

S. schenckii sensu strictu
S. brasiliensis
S. globosa
S. luriei

agricultural workers, forest rangers, horticulturists, etc.

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Sporotrichosis

LABORATORY DIAGNOSIS
> Specimens:_________
> KOH preparations and biopsies are difficult and not sensitive; enhanced with ____ and _____stains.

• Histopathology: non-specific granulomatous reaction, often developing pseudoepitheliomatous hyperplasia

Smears of biopsy material or exudates from ulcerative lesions

GMS and PAS

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Sporotrichosis
LABORATORY DIAGNOSIS

• Sporothrix schenckii:

• Yeasts observed in tissue: usually spherical, multiple budding yeasts, some fusiform or pleomorphic

• shape????

• 2-10m in diameter, single or rarely multiple buds

Elongated, or “cigar-shaped”

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Sporotrichosis

may appear to encapsulated but
this is an artifact caused by shrinkage of the cytoplasm from the cell wall during fixation

when present, the asteroid body is characteristic of it

Splendore-Hoeppli material surrounding yeast cells (non specific)

Sporothrix schenckii

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Sporotrichosis
LABORATORY DIAGNOSIS
> Culture: mandatory, gold standard for diagnosis;______ (25C) /______(37C), growth on SDA in 8 days

> Inhibitory Mold or SDA containing antibiotics incubated at 25 to 30 °C

> confirmation: growth at 35 °C and conversion to the yeast form (BHIA with blood)

> Colonies: blackish/gray/whitish, shiny, wrinkled/fuzzy with age

mycelial phase/ yeast phase

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Sporotrichosis
> Microscopy:

Narrow, hyaline, branching, septate hyphae, abundant distinctive ovoid conidia, 3-5 um, clustered at the ends of tapering conidiophores (rosette, daisy petal formation)

Sporothrix schenckii

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Sporotrichosis

Macromorphology of________;

Micromorphology reveals delicate, hyaline septate hyphae, conidiophore that originates primary hyaline conidia in a bouquet arrangement

Sporothrix brasiliensis

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Sporotrichosis
LABORATORY DIAGNOSIS

> ____________- a cell-mediated immune response within 48h

(not standardized nor accepted in several countries)

Intradermal sporothricin (sporotrichin) skin test

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Sporothriocis LD

detects antibodies against SsCBF (Ss cell wall antigen with high sensitivity and specificity)

> ELISA test

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Sporothricosis
LD

useful for rapid diagnosis

> PCR test

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•A subcutaneous mycotic infection that is usually caused by traumatic inoculation of any of the recognized fungal agents, which reside in soil and vegetation;

“chromomycosis”

Chromoblastomycosis (CBM)

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• Infection: Chronic & characterized by the slow development of progressive granulomatous lesions that in time induce hyperplasia (crusted, nodular, verrucose) of the epidermal tissue.

•Host reaction: suppurative and granulomatous, with dermal fibrosis & pseudoepithelomatous hyperplasia, if left untreated - co-bacterial infection, neoplastic transformation - epidermoid carcinoma

Chromoblastomycosis

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• Epidemiology: Worldwide, more common in bare footed populations in tropical regions.

Highest prevalence in Amazon region of Brazil, northern part of Venezuela, & in Madagascar.

Most frequently males.

Not transmitted from human to human.

WHO: NTD

Chromoblastomycosis

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Chromoblastomycosis

• Etiological Agents (most common):
(3)

• Fonsecaea pedrosoi
• Cladophialophora carrionii
• Phialophora verrucosa

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MORPHOLOGY & IDENTIFCATION:

• Dematiaceous fungi are similar in their pigmentation, antigenic structure, morphology & physiologic properties

• In tissues (biopsy): appear the same - spherical brown cells, 4-12um diameter, termed “muriform” or “sclerotic bodies” or “Medlar bodies,” planate-dividing (divide by transverse septation), with delayed separation may give rise to a cluster of 4-8 cells.

• In crusts (skin scrapings) or exudates: may germinate into septate, branching hyphae

Chromoblastomycosis

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Skin scrapings from a patient with________ mounted in 10%-20% KOH and Parker ink solution showing characteristic ***brown pigmented,*** planate-dividing, ***rounded sclerotic bodies.***

Chromoblastomycosis

• Identification: • Culture characteristics & microscopic morphology are important, esp. CONIDIAL morphology, the ARRANGEMENT of conidia on the conidiogenous cell & the ***morphology of the conidiogenous cell.*** ***Cellotape flag/slide culture preparations recommended.***

Chromoblastomycosis

Chromoblastomycosis ***Fonsecaea pedrosoi*** (siblings:2)

F. monophora & F. nubica

Chromoblastomycosis • Colonies: (Surface) black-brown to olive-gray in color, with velvety to fluffy texture, 45-50 mm diameter. Reverse: dark olive gray to black • Microscopic: polymorphic, sparingly branched, brownish conidiophores produce clusters of ***1-celled club-shaped conidia*** in ***SHORT chains, septate hyphae***

Foncasaea pedrosoi

Chromoblastomycosis Neurotropic-brain abscess

Cerebral PHM

Chromoblastomycosis • ***Club-shaped conidia*** in short branching chains arising from phialides & septate, brownish, conidiophores.

Fonsecaea pedrosoi

- ***rare agent*** of chromoblastomycosis

Fonsecaea compacta

Chromoblastomycosis .: Polymorphic - ***Rhinocladiella-like, Cladosporium-like, Phialophora-like forms;*** produce ***several types of conidiophores.*** • Colonies: Slow growing, velvety-woolly, ***olive to olivaceous black in color*** • Diagnostic form: densely, clustered, one-celled, pale brown, primary conidia, up to 4x8 um, irregularly swollen, club-shaped conidiophores. Primary to secondary to tertiary conidia formation.

• Fonsecaea spp

Chromoblastomycosis on Sabouraud's dextrose agar. Colonies: slow growing, reaching 3-4 cm in diameter after 1 month, with a ***compact suede-like to downy surface.*** Colonies are olivaceous-black in colour and have well defined margins. Microscopic morphology shows typical conidial ontogeny with elongate conidiophores producing ***branched acropetal (from base to apex) chains of smooth-walled conidia.***

Cladophialophora carrionii (formerly Cladosporium) C. carrionii

Chromoblastomycosis • Showing ***branched acropetal*** (from base to apex) chains of smooth-walled conidia arising from elongate conidiophores.

Cladophialophora carrionii

Chromoblastomycosis on Sabouraud's dextrose agar. Colonies are slow growing, ***initially dome-shaped, later becoming flat, suede-like and olivaceous to black in colour.*** well-formed, ***flask-shaped or elliptical phialides*** (distinctive widely-flaring, ***pigmented collarettes*** ). Single-celled phialoconidia (spherical-oval) are produced in ***basipetal succession & aggregate*** in slimy heads at the apices of the phialide.

Phialophora verrucosa

Chromoblastomycosis Key features: Characteristic ***flask-shaped phialides*** with distinctive funnel-shaped, darkly pigmented collarettes.

Phialophora verrucosa

Chromoblastomycosis Surveillance and control • Accurate data on the incidence and prevalence are not available. • Considered an occupational disease, occurring among…

farm laborers, babassu coconut harvesters, lumberjacks, or vendors of farm products

•A rare infection caused by a number of ***dematiaceous (pigmented) frequently reported in tropical & subtropical countries.***

Phaeohyphomycosis

Phaeohyphomycosis •Four clinical forms:

superficial cutaneous or corneal subcutaneous visceral forms

Phaeohyphomycosis •______-similar to tinea nigra •_______-phaeomycotic cyst • Invasive or disseminated (neurotropic, brain)

Superficial infections Subcutaneous cysts

•Opportunistic infections ***mostly affect the immunocompromised*** with widespread disease. •Risk factors: skin wounds, compromised immunity due to ***immunosuppressant medications, *** certain underlying chronic health conditions (diabetes, tuberculosis) •Malignancies such as ***lymphoma & leukemia*** •Use of topical or systemic corticosteroids

Phaeohyphomycosis

•Tissue morphology of the causative organism is ***mycelial, darkly pigmented septate.*** • ***Dark irregular hyphae in tissue*** - separates it from other clinical types of disease involving brown-pigmented fungi where the tissue morphology of the organism is a grain (mycotic mycetoma) or sclerotic body (chromoblastomycosis).

Phaeohyphomycosis

• Distribution: Worldwide. Rare. • Etiological Agents: Numerous and diverse (>100) dematiaceous hyphomycetes (found in soil and plant debris)

Phaeohyphomycosis

Phaeohyphomycosis (skin, neurotropic, cerebral, fatal)

Cladophialophora bantiana

Phaeohyphomycosis ***The Black fungus.*** Grow slowly. Incubation at 25°C. Colonies-initially moist, yeast-like, shiny. Aerial hyphae after 3 to 4 weeks. Color black, front and reverse. Can grow as high as 42°C and does not assimilate potassium nitrate.

Exophiala (Wangiella) dermatitidis

Phaeohyphomycosis Conidiophores, vegetative hyphae. Phialides-brown, ***flask-shaped to cylindrical, do not have collarettes*** Conidia (2-4 x 2.5-6 um) - round to oval in clusters at the apices of the phialides & down the sides of the conidiophores

Exophiala (Wangiella) dermatitidis

Phaeohyphomycosis The initial yeast-like phase is characterized by ***unicellular, ovoid to elliptical, budding yeast-like cells.*** The yeast-like cells are ***hyaline and thin-walled when young becoming darkly pigmented (dematiaceous) and thick-walled when mature.*** With the development of mycelium, ***flask-shaped to cylindrical annellides are produced.*** Conidia are hyaline to pale brown, one-celled, round to obovoid, 2-4 x 2.5-6 um, smooth-walled and accumulate in slimy balls at the apices of the annellides or down their sides. Cultures grow at 42C and on media containing 0.1% cycloheximide.

Exophiala dermatitidis

Phaeohyphomycosis Colonies ***- initially smooth, greenish-grey to black, mucoid, yeastlike,*** becoming raised, tufts of aerial mycelium, dome-shaped, suedelike. Reverse: ***olivaceous black.***

Exophiala jeanselmei

Phaeohyphomycosis ***Ellipsoidal, yeast-like, budding cells in young cultures.*** Scattered amongst these yeast-like cells are larger, inflated, subglobose to broadly ellipsoidal cells (germinating cells) which give rise to ***short toulose hyphae that gradually change into unswollen hyphae. *** Conidia are formed on lateral pegs either arising apically or laterally at right or acute angles from essentially undifferentiated hyphae or from strongly inflated detached conidia. Conidiogenous pegs are 1-3 um long, slightly tapering and imperceptibly annellate. Conidia are hyaline, smooth, thin-walled, broadly ellipsoidal, 3.2-4.4 x 1.2-2.2 um, and with inconspicuous basal scars. Cultures grow at 37C but not at 40C.

Exophiala jeanselmei

Phaeohyphomycosis-disseminated Microscopic findings: a) hyperkeratosis, acanthosis, hemorrhage in the epidermis, and dense inflammatory infiltrate in the dermis, H&E, X100 b) LARGE BROWN SPORES within & outside giant cells. HEx400. c) BROWN SEPTATE HYPHAE, Masson-Fontana stain x400.

Cladophialophora bantiana

Phaeohyphomycosis-disseminated CULTURE/Microscopic findings: a) Irregular, velvety, gray colored colonies with black reverse. b) Septate hyphae with unicellular conidia branching at acute angles, x400

Cladophialophora bantiana

Phaeohyphomycosis may be distinguished from Cladosporium species by the (1) absence of conidiophores, ***"shield cells,"*** or ***prominent hila (attachment points)*** (2) ability to grow on media with cycloheximide; (3) having dry, non-fragile chains of conidia, (4) ability to grow at 42°C (compared with Cladophialophora carrionii which has a maximum growth temperature of 35-37°C and Cladosporium species which have a maximum of less than 35°C.

C. bantiana

• consists of central, basophilic yeast cell surrounded by radiating extensions of eosinophilic material; rays contain antigen- antibody complexes, complement, and tissue components (PAS)

asteroid body S schenckii

Colonies stained with lactophenol cotton blue dye after tableting and coating and subsequently observed under a microscope (1000x magnification). Clear and divided mycelia could be observed with slender, branched, and tapered tips (A). Conidium stalks appeared ***pear-shaped*** and were clustered similarly to flowers (B). Conidium was arranged conically along the axis.

S globosa

Note tissue hyperplasia - formation of ***verrucoid, warty cutaneous nodules*** raised 1 to 3 cm above the skin surface.

Chromoblastomycosis of the foot due to P. verrucosa.

• In tissues (biopsy): appear the same - spherical brown cells, 4-12um diameter, termed ***"muriform" or "sclerotic bodies"*** or ***"Medlar bodies,"*** planate-dividing (divide by transverse septation), with delayed separation may give rise to a cluster of ***4-8 cells.*** • In crusts (skin scrapings) or exudates: may germinate into septate, branching hyphae

Chromoblastomycosis

Incubation at 25°C. Colonies-initially moist, yeast-like, shiny. Aerial hyphae after 3 to 4 weeks. Color black, front and reverse. Can grow as high as 42°C and does not assimilate potassium nitrate.

Exophiala (Wangiella) dermatitidis

Scattered amongst these yeast-like cells are larger, inflated, subglobose to broadly ellipsoidal cells (germinating cells) which give rise to ***short torulose hyphae*** that gradually change into ***unswollen hyphae.***

E jeanselmei

Conidia are formed on ***lateral pegs*** either arising apically or laterally at right or acute angles from essentially undifferentiated hyphae or from strongly inflated detached conidia.

E jeanselmei

Subcutaneous Mycoses Flashcards

(60 cards)