Subcutaneous & Systemic Mycoses

TRANSCRIBED GEN CAMATO

SUBCUTANEOUS & SYSTEMIC MYCOSES SUBCUTANEOUS & SYSTEMIC MYCOSES MYCOLOGY AND VIROLOGY | LECTURE

1

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

Fixed cutaneous verrucous-type sporotrichosis of the wrist and hand

Microscopic morphology of the saprophytic or mycelial form of Sporothrix schenckii when grown on Sabouraud's dextrose agar at 25oC. Note the daisy-like microconidia

Microscopic morphology of the parasitic or yeast form of Sporothrix schenckii when grown on brain heart infusion agar containing blood and incubated at 370C. Note budding yeast cells.

439

Sporothrix schenckii on Sabouraud's dextrose agar grown at 25oC colonies are moist and glabrous, with a wrinkled and folded surface. Pigmentation may vary from white to cream to black

Subcutaneous Mycoses } Involve the deeper layers of the skin, including the cornea,

muscle, and connective tissue } Caused by saprophytic fungi that lives on soil or on

vegetation } Occurs by direct implantation of spores or mycelia fragments

into a puncture wound in the skin } The host immune system recognizes the fungi, resulting in

variable tissue destruction and frequently epitheliomatous hyperplasia

} Tend to remain localized and rarely disseminate systemically } Types of Subcutaneous Mycoses:

c Sporotrichosis c Chromomycosis c Mycetoma c Rhinosporidiosis c Lobomycosis c Entomophthoromycosis

SPOROTICHOSIS

} ‘Rose gardener’s disease’ ê Thorns of roses would inoculate the spores

} Classic infection is associated with traumatic inoculation of soil or vegetable or organic matter contaminated with the fungus

} Chronic mycotic infection of the cutaneous or subcutaneous tissues and adjacent lymphatics characterized by nodular lesions which may suppurate and ulcerate

} Occasionally involve the CNS, lungs (Pulmonary sporothricosis) or genitourinary tract

} ETIOLOGIC AGENT: ê Sporothrix schenkii ê Thrives on vegetation ê Dimorphic fungi

� Ambient temp= MOLD � In vitro or tissue @ 35°C - 37°C= small

budding YEAST ê Grows in soil and decaying vegetation

} PATHOGENESIS & CLINICAL FINDINGS: ê Trauma to the skin introduces the conidia or hyphal

fragments ê Initial lesion usually on the lower extremities

� Can also be anywhere � In children, often with facial lesions

} Fixed Sporotrichosis ê Single nonlymphangitic nodule ê Limited and less progressive ê Endemic areas where there is high immunity

level } Lymphocutaneous sporotrichosis

ê Initial lesion develops as a granulomatous nodule that may progress to form a necrotic or ulcerative lesion

ê Multiple subcutaneous nodules and abscesses ê Occur along the lymphatics.

} LABORATORY DIAGNOSIS ê Specimens

� Specimens include biopsy material or exudate from granulous or ulcerative lesions.

ê Microscopic Examination � Sensitivity can be enhanced by

Gomori's and periodic acid-Schiff stain � Mold – flowerette or daisy-like conidia � Yeast – cigar-shaped yeast cell � Asteroid body

Often seen in tissue Consists of a central basophilic

yeast cell surrounded by radiating extensions of eosinophilic material, which are depositions of antigen- antibody complexes and complement

ê Culture � Most reliable method of diagnosis � Specimens are streaked on inhibitory

mold agar or Sabouraud's agar containing antibacterial antibiotics and incubated at 25-30 °C

� The identification is confirmed by growth at 35°C and conversion to the yeast form.

} TREATMENT ê Ocassionally self-limiting ê Oral administration of saturate solution of

Potassium Iodide in milk ê Oral itraconazole or other azoles



2

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

Chronic verrucose chromoblastomycosis of the foot due to Phialophora verrucosa. Note tissue hyperplasia characterized by the formation of verrucoid, warty cutaneous nodules raised 1 to 3 cm above the skin surface

Phialophora)type)

Phialophora verrucosa •  flask-shaped or elliptical

phialides with flaring collarettes

•  phialospores on top of the phialide

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phialide

phialospores

Cladosporium,type,

CHROMOMYCOSIS/CHROMOBLASTOMYCOSIS } Mycotic infection characterized by the development in tissue

of dematiaceous (brown-pigmented), planate-dividing, rounded sclerotic bodies (also called Muriform or Medlar bodies)

} Occurs mainly in tropics, usually observed on legs of barefooted agrarian workers

} ETIOLOGIC AGENTS

ê Phialophora verrucosa ê Fonsecaea pedrosoi ê Rhiniocladiella aquaspersa ê Fonsecaea compacta ê Cladosporium carrionii ê All dematiaceous ê Grow on woody plants and in the soil

} PATHOGENESIS & CLINICAL FINDINGS ê Agents often gain entry into the human body by

contact with wood splinters or thorns. ê Early lesions are small, warty papules and ê Usually enlarge only slowly. ê Over years lesions become crusted, verrucose,

wart-like with extension along the draining lymphatics

ê Cauliflower-like nodules with crusting abscesses eventually cover the area

} LABORATORY DIAGNOSIS ê clinical presentation histopathologic findings of

chestnut-brown, sclerotic bodies } CULTURE

ê Slow growing ê Suede like ê Olive black in color

} MICROSCOPIC MORPHOLOGY ê Microscopic Morphology ê Species can be differentiated by studying the

types of sporulation: ê Cladosporium – conidia in branching chain

formation ê Phialophora - production of vase or flask-shaped

conidiophore ê Acrotheca – conidia surrounding the swollen,

knotted, club-shaped terminal ends of hyphae

ê Phialophora verrucosa � Phialophora type

ê Cladosporium carrionii � Cladosporium

ê Rhinocladiella aquaspersa � Acrotheca type

ê Fonsecaea pedrosoi � acrotheca type

ê Fonsecaea compacta � May exhibit all 3 types of sporulation � Smaller conidia and more compact than

F. pedrosoi Phialophora type ª Phialophora verrucosa

§ Flask-shaped or elliptical phialides with flaring collarettes

§ Phialospores on top of the phialide

Cladosporium type ª Cladosporium carrionii

Acrotheca type ª Rhinocladiella aquaspersa ª Fonseceae pedrosoi ª Fonseceae compacta

� May exhibit all 3 types of conidiation

} TREATMENT ê itraconazole and terbinafine ê Because of the risk of recurrences developing

within the scar, surgery is not indicated



3

Mycetoma)

• Human & animal infection characterized by: ▫ draining sinuses ▫ granules vary in ! Size ! color ! hardness

Grains of Madurella mycetomatis (tissue microcolonies) are brown or black, 0.5 to 1.0 mm in size, round or lobed, hard and brittle, composed of hyphae which are 2 to 5 um in diameter, with terminal cells expanded to 12 to 15 (30) um in diameter

subcutaneous

Mycetomaa)

•  etiologic agents ▫ EUMYCOTIC MYCETOMA

•  Curvularia

www2.truman.edu

www.dehs.umn.edu

www.mold.ph

subcutaneous

Mycetoma)

www.biologie.uni-halle.de

• Etiologic agents •  EUMYCOTIC MYCETOMA

▫ Leptosphaeria

subcutaneous

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Mycetoma)

• Etiologic agents

▫ EUMYCOTIC MYCETOMA

• Pseudallescheria

MYCETOMA } Human & animal infection characterized by:

ê Draining sinuses ê Granules vary in

-Size -Color

-Hardness

ê caused by traumatic implantation of spores ê involves cutaneous & subcutaneous tissues, fascia &

bone of foot or hand } ETIOLOGIC AGENTS:

ê Actinomycotic mycetoma (caused by bacteria): ¶ Nocardia ¶ Actinomadura ¶ Streptomyces

ê Eumycotic mycetoma (caused by fungi): ¶ Madurella ¶ Acremonium ¶ Pseudallescheria ¶ Exophiala ¶ Leptosphaeria ¶ Curvularia ¶ Fusarium ¶ Aspergillus

} PATHOGENESIS & CLINICAL FINDINGS ê The earliest lesion is a small, painless,

subcutaneous nodule or plaque that increases slowly but progressively in size

ê As the mycetoma develops,the affected area gradually enlarges and becomes disfigured as a result of chronic inflammation and fibrosis.

ê With time, sinus tracts appear on the skin surface and drain serosanguineous fluid that often contains grossly visible granules.

ê The infection commonly breaches tissue planes and destroys muscle and bone locally

} LABORATORY DIAGNOSIS ê Key to the diagnosis of eumycotic mycetoma is the

demonstration of grains or granules ê Grains can be visualized microscopically by

mounting in 20% KOH. ê Grains are easily visualized in tissue stained with

H&E ê Culture is usually necessary for definitive

identification of the organism.

} ETIOLOGIC AGENTS: r Eumycotic mycetoma

ê Curvularia

ê Leptosphaeria

ê Pseudallescheria

ê Aspergillus

} TREATMENT

ê Response to amphotericin B, ketoconazole, or itraconazole is variable and often poor, although such therapy may slow the course of infection

ê Promising treatment responses have recently been reported for terbinafine, voriconazole, and posaconazole

ê Local excision is usually ineffective or not possible, and amputation is the only definitive treatment



4

•  Mature spherule with endospores typical of rhinosporidiosis.

Lobomycosis showing extensive verrucoid lesions on the legs

•  Grocott’s methenamine silver (GMS) stained tissue section showing numerous darkly pigmented yeast-like cells, often in chains, 9-12 um in size typical of Loboa loboi.

Entomophthoromycosis caused by Basidiobolus ranarum showing an ulcerated subcutaneous lesions on the abdomen of a young boy from Darwin.

Entomophthoromycosis caused by Basidiobolus ranarum showing a subcutaneous lesion involving the entire thigh and buttock of an Indonesian boy.

Haematoxylin and eosin (H&E) stained section of tissue from a lesion on a child's arm showing broad septate hyphae surrounded by an eosinophilic sheath (Splenodore-Hoeppli phenomenon) typical of Entomophthoromycosis

•  Microscopic morphology of Basidiobolus ranarum showing numerous round, smooth, thick-walled zygospores

Entomophthoromycosis caused by Conidiobolus coronatus in a patient seen at the Pasteur Institute in Paris in 1972 from the then French Camaroons. Note the massive swelling and distortion of the subcutaneous tissue of the nasal and perioral regions, with a large polypoid protrusion on the inner aspect of the lower lip.

•  Microscopic morphology of Conidiobolus coronatus showing several mature, spherical sporangiola (conidia) with hair-like appendages, called villae and prominent papillae, marking the site of former attachment to the sporangiophore.

RHINOSPORIDIOSIS } Is an infection of the mucocutaneous tissue caused by

Rhinosporidium seeberi } Causes a chronic granulomatous disease characterised by

the production of large polyps, tumours, papillomas, or wart-like lesions.

} The nose is the most commonly affected site.

LOBOMYCOSIS } Chronic, localised, subepidermal infection } Keloidal, verrucoid, nodular lesions or vegetating crusty

plaques and tumours } Loboa loboi - masses of spheroidal, yeast-like organisms in

lesions } Cauliflower-like and hyper or hypopigmented } Etiologic agent known as "Loboa loboi" } PATHOGENESIS AND CLINICAL FINDINGS

ê The initial infection is thought to be caused by traumatic implantation

ê The lesions begin as small, hard nodules resembling keloids and may spread slowly in the dermis and continue to develop over a period of many years.

ê Older lesions become verrucoid and may ulcerate. ê The disease may be transferred to other areas of

the skin by further trauma or autoinoculation. ê 90% of cases are men, mostly in farmers and

other high- risk groups exposed to various harsh conditions as well as aquatic habitats

} CONTROL ê Wide surgical excision of the affected area ê Clofazimine ê Slow and chronic and the although not life

threatening the prognosis is poor.

ENTOMOPHTHORMYCOSIS } Also known as Subcutaneous zygomycosis } Etiologic agents:

¶ Conidiobolus coronatus (upper part of the body, face)

¶ Basidiobolus ranarum (lower, legs) } Entomophthoromycosis caused by Basidiobolus } Chronic inflammatory or granulomatous disease generally

restricted to the limbs, chest, back or buttocks } Primarily occurring in children with predominance in males. } Initially, lesions appear as subcutaneous nodules, which

develop into massive, firm, indurated, painless swellings, which are freely movable over the underlying muscle but are attached to the skin which is hyperpigmented but not ulcerated.

} Etiologic Agent: ¶ Basidiobolus ranarum (= B. haptosporus)

commonly present in decaying fruit and vegetable matter, and as a commensal in the intestinal tract of frogs, toads and lizards.

} Entomophthoromycosis caused by Conidiobolus } A chronic inflammatory or granulomatous disease that is

typically restricted to the nasal submucosa and characterized by polyps or palpable restricted subcutaneous masses.

} Human infections occur mainly in adults with a predominance in males (80% of cases).

} Distribution: Worldwide, especially tropical rain forests of Africa.

} Aetiological Agent: Conidiobolus coronatus, commonly present in soil and decaying leaves.

} Laboratory Diagnosis ê Both types of subcutaneous zygomycosis require

biopsy for diagnosis ê Morphology: Short, poorly stained hyphal

fragments, surrounded by eosinophilic Splendore-Hoeppli material

} Treatment: ê Both types of infection may be treated with

itraconazole. ê Facial reconstructive surgery may be necessary ê in the case of C. Coronatus infection



5

322

Histoplasmosis of the lower gum showing ulcer around base of tooth.

327

Microscopic morphology of the saprophytic or mycelial form of Histoplasma capsulatum showing characteristic large, rounded, single-celled, tuberculate (with spike-like projection) macroconidia formed on short, hyaline, undifferentiated conidiophores.

323

Tissue section stained with haematoxylin and eosin (H&E) from a biopsy of the mouth lesion shown in slide 7. Note macrophages containing numerous yeast cells of Histoplasma capsulatum

329

Microscopic morphology of the parasitic or yeast form of Histoplasma capsulatum cultured on brain heart infusion agar containing blood incubated at 37oC. Note the small round to oval budding yeast-like cells.

325

Culture of Histoplasma capsulatum on Sabouraud's dextrose agar showing a white suede-like colony with a pale yellow-brown reverse.

326

Culture of Histoplasma capsulatum on Sabouraud's dextrose agar showing a pale yellow- brown reverse.

332

exoantigen immunodiffusion test kit for the identification of Histoplasma capsulatum

333

Exoantigen immunodiffusion plate showing positive identification of Histoplasma capsulatum. Note H and M bands of identification; EX = culture filtrate; H = Histoplasma antibody and antigen, C = Coccidioides antibody and antigen; B = Blastomyces antibody and antigen.

Systemic Mycoses } Deep w/in the body } Caused by fungi that live in the soil } Typically begins in the lungs then spread to other body

tissue } Not contagious } Types of Systemic Mycoses:

¶ Histoplasmosis ¶ Coccidiodomycosis ¶ Blastomycosis ¶ Paracoccidiomycosis

HISTOPLASMOSIS

} Also known as Cave disease, Darling's disease, Ohio valley disease, Spelunker’s Lung and Caver's disease

} Intracellular mycotic infection of the reticuloendothelial system caused by the inhalation of the fungus

} Approximately 95% of cases of histoplasmosis are inapparent, subclinical or benign.

} Five percent of the cases have chronic progressive lung disease, chronic cutaneous or systemic disease or an acute fulminating fatal systemic disease

} All stages of this disease may mimic tuberculosis. } Distribution: World-wide, especially U.S.A. Sporadic cases

do occur in Australia. } Aetiological Agent: Histoplasma capsulatum, especially

from soil enriched with excreta from chicken, starlings and bats.

} Laboratory Diagnosis: ê Specimen: Sputum, bronchoalveolar lavage (BAL)

, blood, bone marrow, tissue ê Morphology in Culture

¶ Room Temp (25°C); Saprobic phase - Mold with tuberculate macroconidia and small, oval microconidia

¶ Body Temp (37°C); parasitic phase – Small budding yeast

ê Serology ¶ Antibody: complement fixation,

Immunodiffusion ¶ Antigen: serum and urine

COCCIDIOMYCOSIS

} Commonly known as San Joaquin Valley fever } Initially, a respiratory infection, resulting from the inhalation

of conidia, that typically resolves rapidly leaving the patient with a strong specific immunity to re-infection

} Sometimes the disease may progress to a chronic pulmonary condition or as a systemic disease involving the meninges, bones, joints and subcutaneous and cutaneous tissues.

} Distribution: endemic in south-western USA, Northern Mexico and various centres in South America

} Aetiological Agent: Coccidioides immitis, a soil inhabiting fungus considered as the most virulent of all human mycotic pathogens; major biohazard to laboratory personnel

} Laboratory Diagnosis: ê Specimen: Sputum, bronchoalveolar lavage (BAL)

, tissue ê Morphology in Culture

¶ Room Temp (25°C); Saprobic phase - Mold with barrel-shaped arthroconidia

¶ Body Temp (37°C); parasitic phase – Spherul containing endospores


Immunodiffusion, tube precipitin, latex particle agglutination



6

Ulcerated granuloma due to B. dermatitidis.

051

Cutaneous blastomycosis of 20 years duration showing loss of skin.

Cutaneous blastomycosis from the same patient as in slide 31 showing loss of skin from the arm and fingers.

Blastomyces dermatitidis mold phase.

Giemsa stain of Blastomyces dermatitidis showing broad-based budding yeast

Coccidioidomycosis showing chronic lesions of the face. Active lesions are seen on the cheek. An atrophic, depigmented scar representing a healed lesion is on the forehead.

Chronic cutaneous coccidioidomycosis showing granulomatous lesions on face, neck and chin

106

Extension of pulmonary coccidioidomycosis showing a large superficial, ulcerated plaque.

112

Microscopic morphology of Coccidioides immitis showing typical single-celled, hyaline, rectangular to barrel-shaped, alternate arthroconidia, separated from each other by a disjunction cell.

113

Microscopic morphology of Coccidioides immitis showing typical single-celled, hyaline, rectangular to barrel-shaped, alternate arthroconidia, separated from each other by a disjunction cell

107

Direct microscopy of skin scrapings from a cutaneous lesion mounted in 10% KOH characteristic endosporulating spherules

The presence of spherules with endospores is and Parker ink solution showing (sporangia) of Coccidioides immitis. diagnostic.

109

Periodic Acid-Schiff (PAS) stained tissue section of viscera from an experimentally induced infection in a mouse showing typical endosporulating spherules of Coccidioides immitis. Young spherules have a clear centre with peripheral cytoplasm and a prominent thick wall. Endospores (sporangiospores) are later formed within the spherule by repeated cytoplasmic cleavage. Rupture of the spherule releases endospores into the surrounding tissue where they re-initiate the cycle of spherule development.

110

Culture of Coccidioides immitis on Sabouraud's dextrose agar showing a suede-like to downy, greyish white colony

111

Culture of Coccidioides immitis on Sabouraud's dextrose agar showing a tan to brown reverse.

(continuation… Coccidiomycosis)

BLASTOMYCOSIS } Also known as North American Blastomycosis,

Gilchrist’s disease and Chicago disease } Chronic granulomatous and suppurative disease having a

primary pulmonary stage that is frequently followed by dissemination to other body sites, chiefly the skin and bone

} Distribution: North America, some cases from Africa, Asia and Europe.

} Aetiological Agent: Blastomyxes dermatitidis, a soil inhabiting fungus.

} Laboratory Diagnosis ê Specimen: Sputum,BAL, lung, tissue, skin biopsy ê Morphology in Culture

¶ Room Temp (25°C); Saprobic phase - Mold, round to oval or pear-shaped conidia; “lolipop conidia”

¶ Body Temp (37°C); parasitic phase – Broad- based,budding yeast


Immunodiffusion, enzyme immunoassay ¶ Antigen: serum and urine



7

383

Mucocutaneous paracoccidioidomycosis showing extensive destruction of facial features.

384

Mucocutaneous paracoccidioidomycosis showing an ulcerated lesion on the lips and loss of teeth

385

Mucocutaneous paracoccidioidomycosis showing an ulcerated lesion on the pharyngeal mucosa.

386

Grocott’s methenamine silver (GMS) stained lung tissue section showing multiple, narrow base, budding yeast cells "steering wheels" of P. brasiliensis.

387

Microscopic morphology of Paracoccidioides brasiliensis showing multiple, narrow base, budding yeast cells "steering wheels" of P. brasiliensis

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PARACOCCIDIOIDOMYCOSIS } Also known as South American Blastomycosis } Chronic granulomatous disease that characteristically

produces a primary pulmonary infection, often inapparent, and then disseminates to form ulcerative granulomata of the buccal, nasal and occasionally the gastrointestinal mucosa.

} Distribution: geographically restricted to areas of South and Central America

} Aetiological agent: Paracoccidioides brasiliensis } Laboratory Diagnosis:

ê Specimen: Sputum, bronchoalveolar lavage (BAL), tissue

ê Morphology in Culture ¶ Room Temp (25oC); Saprobic phase -

Mold, round microconidia and intercalary chlamydospores

¶ Body Temp (37oC); parasitic phase - multiple, budding yeast; “steering wheel,” “pilot wheel,” “mariner’s wheel”


Immunodiffusion

**Activities FUNGI DISEASE MOLD FORM TISSUE

FORM Blastomyces dermatitidis

Gilchrist’s disease

Lollipop conidia

Broad base budding yeast

Histoplasma capsulatum

Ohio valley disease

Tuberculate macroconidia

Small budding yeast

Coccidioides immitis

San Joaquin valley fever

Barrel shaped arthroconidia

Spherule with endospores

Paracoccidioides brasiliensis

South American blastomycosis

Round macroconidia

Mariner’s wheel

• REFERENCES: Bailey & Scott's Diagnostic Microbiology 12th Ed • Murray, P eat al. Medical Microbiology 6th Ed.

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Subcutaneous & Systemic Mycoses