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Dr.Sharon V.A.KIMS HubballiSubcutaneous mycoses

Deep fungal infectionsDeep fungal infections comprise two distinct groups of conditions,the subcutaneous & systemic mycosesNeither are common,the subcutaneous mycoses,with some exceptions are largely confined to the tropics & subtropics.Systemic mycoses are common among immunocomprised patients AIDS & those receiving treatment for malignancies.

IntroductionSubcutaneous mycoses-Disease in which the pathogen, an exosaprophyte, penetrates the dermis or even deeper during or after skin traumaLesions gradually spread locally without dissemination to deep organsRarely cause deep mycoses in patients with severe underlying abnormalitiesOccurs mostly in tropics

SUBCUTANEOUS MYCOSESMycetomaPhaeohyphomycosisChromoblastomycosis SporotrichosisLobomycosisRhinosporidiosis

MYCETOMA

What is Mycetoma? Mycetoma is a chronic granulomatous, progressive inflammatory disease that involves the subcutaneous tissue after a traumatic inoculation of the causative organism

It may be caused by true fungi (eumycetes) or by higher bacteria (actinomycetes) and therefore it is classified into eumycetoma and actinomycetoma respectively.

Mycetoma Mycetoma was first described in the mid 1800s and initially named Madura foot, after the region of Madura in India where the disease was first identified. This infection results in a granulomatous inflammatory response in the deep dermis and subcutaneous tissue, which can extend to the underlying bone. Characterized by the formation of grains containing aggregates of the causative organisms that may be discharged onto the skin surface through multiple sinuses.

Mycetoma caused by Microaerophilic actinomycetes is termed actinomycetoma, and mycetoma caused by true fungi is called eumycetoma.A common causative organism is Actinomadura madurae, but Madura foot is also caused by other actinomycetes including Streptomyces somaliensis .

Actinomadura spp

MycetomaThe body parts affected most commonly in persons with mycetoma include the foot or lower leg, with infection of the dorsal aspect of the forefoot being typical. The hand is the next most common location; however, mycetoma lesions can occur anywhere on the body.

Mycetoma LesionsLesions on the chest and back are frequently caused by Nocardia species, whereas lesions on the head and neck are usually caused by Streptomyces somaliensis.

Fungal causes differentiated byColonial appearanceGrowth ratePigmentationMicroscopyColour of granulesPhysiological reactions

Clinical featuresActinomycetomaEumycetoma

Causative organismsAerobic actinomycetesHyaline and phaeoid hyphomycetesTumor massMultiple,diffuse with ill-defined mariginsUsually single with well defined marginsSinusesAppear early and more in numberAppear late and relatively less in numberOpening of sinusesRaised, inflamed and flared upFlat opening and not flared upFlap of openingEasily removedNot easily removedDischarge Usually purulentSerous or sero-sanguinousGrainsWhite except A.pelletieri which is redBlack or whiteExtent of involvementMore extensive and obliterative with hypertrophic, punched out osteolytic lesionsLess extensive, only osteosclerotic lesions of bone

Causative agents of Eumycetoma

Madurella mycetomatis (most common)Madurella griseaExophiala jeanselmeiAcremonium sppAspergillus sppFusarium sppScedosporium (Pseudallescheria)

Causative agents of Actinomycetoma

Actinomadura madurae Actinomadura pelletieri Streptomyces somaliensis Nocardia species

Causative fungal agentTextureSize(mm)ShapeCement-like matrixMadurella mycetomatisHard0.5-5Oval to lobedPresent,homogenousMadurella griseaSoft0.3-0.6Oval to lobedPresent,peripheralExophiala jeanselmeiSoft0.2-0.3IrregularAbsentCurvularia geniculataHard0.5-1OvalPresent,peripheral

BLACK GRAIN EUMYCETOMACausative fungal agentsTextureSize(mm)ShapeCement-like matrixPseudallescheria boydiiSoft0.5-1Oval Absent

Aspergillus nidulans1-2Acremonium falciforme0.2-0.5Fusarium species0.2-0.6

WHITE GRAIN EUMYCETOMA

Pathogenesis The causative organism enters through sites of local trauma (eg, cut on the hand, foot splinter, local trauma related to carrying soil-contaminated material). A neutrophilic response initially occurs, which may be followed by a granulomatous reaction. Spread occurs through skin facial planes and can involve the bone. Haematogenous or lymphatic spread is uncommon.

Clinical features of mycetomaThe characteristic triad Tumefaction (tumor-like swelling)Multiple draining sinuses pathognomic of mycetomaSclerotia (granules/ grains in sinuses)

Dissemination - muscles and bonesSites commonly affected feet, lower extremities, hands

Lab diagnosis of mycetomaGranules differ in colour, shape, dimension and compositionTransport in distilled water or sterile normal salineBlack granules usually fungalSmall red granules StreptomycesWhitish yellow granules either bacterial or fungalKOH of granules- presence or absence of hyphaeHistological stains of biopsy from sinus tract

Fine needle Aspiration Cytology of Mycetoma:

Mycetoma can be accurately diagnosed by Fine Needle Aspiration (FNA) cytology. Mycetoma lesion has a distinct appearance in a cytology smear characterised by the presence of polymorphous inflammatory cells consisting of an admixture of neutrophils, lymphocytes, plasma cells.

Identification of pathogens The mycetoma causative organisms can be identified by their textural description morphological and biological activities in pure culture which may include acid fastness optimal temperature proteolytic activity utilization of sugars and nitrogenous compounds. The grains are the source of the culture and they should be alive and free of contaminants and they are usually obtained by deep surgical biopsy.

TreatmentSurgicalEumycetoma- Itraconazole, KetoconazoleActinomycetoma- Streptomycin +/- Dapsone, Cotrimoxazole

Treatment of Mycetoma The treatment of mycetoma depends mainly on its aetiological agent and the extent of the disease. Until recently, in many centres, the only available treatment for mycetoma was amputation or mutilating surgical excision of the affected part

Treatment of Mycetoma Actinomycetoma is amenable to medical treatment with antibiotics and other chemotherapeutic agents. Combined drug therapy is always preferred to a single drug to avoid drug resistance and to eradicate residual infection.The common drugs regimes are:Amikacin sulphate (15 mg/kg) in combination with Co-trimoxazole(14 mg/kg twice daily) is the first line for actinomycetoma treatment.

Surgical Treatment Surgical excision is recommended for small localized lesions, debulking of massive lesions; for better response to medical treatment and for lesions became well encapsulated by medical treatment. Amputation is rarely done nowadays. It is done for very advanced lesions with bad general condition and as a life saving procedure.

BotryomycosisBotryomycosis is a chronic, Suppurative infection characterized by a granulomatous inflammatory response to bacterial pathogens; it may present with cutaneous or, less commonly, visceral involvement . The term botryomycosis is derived from the Greek word botrys (meaning "bunch of grapes") and mycosis (a misnomer, due to the presumed fungal etiology in early descriptions).

BotryomycosisOther terms used to describe botryomycosis include bacterial pseudomycosis, staphylococcal actinophytosis, granular bacteriosis, and actinobacillosis

Lab diagnosis

Demonstration of granules in the infected tissue

The colour and consistency of the granules vary with the different agents

In actinomycotic mycetoma, the grains are composed of very thin filaments, while in mycotic lesions, they are broader and often show septae and chlamydospores

Growth of organisms in culture and physiological and serological tests also help in establishing the diagnosis

Sporotrichosis

SPOROTRICHOSISThis is a chronic infection involving cutaneous, subcutaneous and lymphatic tissue It is frequently encountered in gardeners, forest workers and manual labourers. Pulmonary (acute or chronic).urban alcoholics ,particularly homeless (alcoholic rose garden sleepers disease)

Caused by the thermally dimorphic fungus Sporothrix schenckii25C mold, 37C yeastSaprophytic fungus decaying vegetation, soil, thornsOccupational hazard florists, agricultural workersAlso known as 'Rose thorn disease'

The incidence is highest in the autumn and rst half of the winter (high humidity and temperatures between 16 and 22C) .

These conditions favour saprophytic growth of S. schenckii.

Sporotrichosis is rare in semiarid areas. The fungus grows on decaying vegetable matter, for example the timber in mines

Acquired through direct inoculation into the skin and rarely via inhalation of conidiaFormation of initial chancre then subcutaneous nodules appear followed by ascending lymphangitis. Nodules ulcerateLymphocutaneous lesions on hand and forearm- Skin lesions characteristically follow lymphatic pathwaysCan disseminate to face and joints Rx; Cutaneous potassium iodide, terbinafine; disseminated amphotericin B; itraconizole cutaneous and disseminated

S. schenckii- Mould Form- Hyphae with rosettes and sleeves of conidiaS. schenckii- Yeast Form- Cigar Shaped

Presentation

Spore is the infective stage of the fungus

It causes infection primarily on the hand or the forearm through direct contact of the skin by spores

Typically, infection is introduced in skin through a penetration of thorn

At the site of thorn injury, it causes a local pustule or ulcer with the nodules along the draining lymphatics

Frequently , the regional lymph nodes draining the ulcer enlarge, suppurate and ulcerate

The primary lesion may remain localized or in the immunocompromised individuals may disseminate to involve the bones, joints, lungs and rarely the central -nervous system

Pathogenesis Melanin protects fungus against macrophages attack and phagocytosis.2 extracellular proteinases-fungal invasion and growth. proteinase I-serine proteinase by chymostatinproteinase II-aspartic proteinase by pepstatin

Asteroid bodies-central yeast surrounded by eosinophilic spicules.3 granulomatous patterns:Sporotrichoid type-concentric zones with necrotic material in the centre surrounded by epitheloid histiocytesTuberculoid type- merges into the area of epitheloid cellsForeign body type

Laboratory diagnosis

Specimens

The samples to be collected include aspiration fluid, pus, biopsy material, skin scrapings and swabs

Microscopy

KOH mount of specimen or histopathological examination of tissue sections stained by methanamine silver stain

The characteristic feature is the asteroid body; a rounded or oval, basophilic, yeast-like body 3-5 um in diameter, with rays of an eosinophilic substance radiating from the yeast cell

Culture

The fungus may not be demonstrable in pus or tissue.

Hence, culture is done on media incubated at 250C and 370C

Slender (2-m) hyphae bear small, oval to pyriform, hyaline conidia produced along the sides of the hyphae and sympodially at the ends of delicate conidiophores arising at right angles from the hyphae.

The arrangement of the conidia at the apex of the conidiogenous cell is often described as palmate or ower-like, with each conidium attached by a denticle to the small vesicle

Microscopic morphology of the saprophytic or mycelial form of Sporothrix schenckii when grown on Sabouraud's dextrose agar at 25oC. Note clusters of ovoid conidia produced sympodially on short conidiophores arising at right angles from the thin septate hyphae.

45440.

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.

46441.

Serology

Serological tests are especially helpful in the diagnosis of extracutaneous or systemic infection

A slide latex agglutination test, using peptido-L-rhamno- D-mannan as antigen is a reliable, sensitive and specific test

Treatment

For cutaneous infection, potassium iodide given topically or orally

For lymphocutaneous infection, itraconazole is effective

For disseminated infection, amphotericin B is the drug of choice

5 clinical types:Lymphocutaneous sporotrichosisFixed cutaneous sporotrichosisMucocutaneous sporotrichosis traumaticDisseminated sporotrichosis implantation

Pulmonary sporotrichosis- inhalation of conidia

Clinical features:

The main clinical varieties of sporotrichosis are the cutaneous and the systemic forms.

In turn cutaneous sporotrichosis is normally divided into two main types, the lymphangitic and xed forms.

occasionally atypical varieties such as mycetoma-like or cellulitic forms may occur

Lymphocutaneous form:

The most common type of sporotrichosis is the localized lymphatic variety, which follows the implantation of spores in a wound.

usually occurs on exposed skin, often on the upper and lower extremities, and is known as lymphangitic sporotrichosis. Incubation period- 8 to 30 days

A nodule or pustule forms, which may break down into a small ulcer

Untreated the disease usually follows a chronic course, which is characterized by involvement of lymphatics from the draining area, a chain of lymphatic nodules develops. -Sporotrichoid

New nodules appear at intervals of a few days. These soften and ulcerate, and are connected by tender lymphatic cords.

A thin purulent discharge may come from the primary lesion and the earliest lymphatic nodules.

As the disease becomes chronic, the regional lymph nodes become swollen and may break down. The primary lesion may heal spontaneously leaving the lymphatic nodes enlarged

Mucocutaneous sporotrichosis:Lesions in mouth, pharynx, vocal cords or noseAt first erythematous,ulcerative and suppurative at first Eventually become granulomatous,vegetative or papillomatous.Accompanied by pain.

Fixed type:

where the pathogen remains more or less localized at the point of inoculation, is less common. The lesions may be acneiform, nodular, ulcerated or verrucous; the latter form is occasionally very extensive. Less commonly, there may be inltrated plaques or red scaly patches. An ulcer may be gummatous or may simulate an epithelioma.

The plaques may suggest leishmaniasis or tuberculosis.

It is thought that this variety may reect a high degree of immunity on the part of the patient.

The variable morphology of this type is notable

Pulmonary Sporotrichosis:The less common systemic form probably follows inhalation, and presents either with local pulmonary disease or focal or widely disseminated lesions in the joints, meninges and skin. Single cavitary lesion of the upper lobe is the most distinctive feature.Gradually chronic pneumonitis wit thin walled cavities with fibrosis and pleural effusion.Spotrichoma- solitary residual fibrocaseous nodules.

Radiology : patches of pneumonitis with widespread miliary infiltration Mediastinal widening There is some evidence that systemic sporotrichosis occurs in patients with some defect in host defence, such as alcoholics.

Where sporotrichosis has been reported in AIDS patients, the lesions have usually been widespread and have affected internal organs as well as the skin.

contrast to the cutaneous variety, which occurs in perfectly healthy individuals.

Sporotrichosis in AIDS patients, the lesions have usually been widespread and have affected internal organs as well as the skin.

In the systemic type, which is rare, ulcerated nodules may develop anywhere on the body or mucous membranes, and visceral lesions may occur

If untreated, this type is fatal but systemic sporotrichosis is exceedingly rare

Lab diagnosis:S. schenckii is very rarely present in quantity in infected tissues, and direct microscopy of clinical material is of little or no value in conrming a diagnosis.

Fluorescent antibody techniques have been successfully employed in locating the pathogenic phase in vivo.

The fungus grows readily on common agar media.

Cigar bodies represent the elongated yeast like form of the fungus and when these yeast forms are surrounded by eosinophilic hyaline ray like processes they are referred to as sporothrix asteroid,usually seen in the centre of suppurative granulomas

The colonies are leathery, moist and initially white or cream with a wrinkled surface.

As the colonies age, they may become progressively darker until they are brown or black

Physiological tests: To conrm the identication, it is essential to convert this thermally dimorphic fungus to the yeast phase, as fungi that are non-pathogenic and morphologically very similar may be isolated as contaminants.

This is best achieved on brainheart infusion agar supplemented with sheeps blood and incubated at 37C. The yeasts are typically oval or cigar-shaped

Treatment:

Localised lymphangitic: Potassium iodide in large oral doses is effective in the localized types, and should be continued for 34 weeks after clinical cure. It is cheap and effective, although side effects are common.(hypersalivation & nausea)A recommended schedule is ve drops initially, increasing to 46 mL of saturated potassium iodide three times daily.

If unresponsive, Itraconazole 100200 mg/day or terbinane 250 mg/day are both effective and well tolerated or iv amphotericin B Systemic form: Itraconazole 100200 mg/day or terbinane 250 mg/day

intravenous amphotericin B may also be helpful

In all cases treatment is continued for at least 1 week after clinical resolution

the local application of heat may produce recovery in some patients.

Differential diagnosis:

Mycobaterial infections

Leishmaniasis

Mycobacterium marinum infection (sh-tank granuloma) may closely resemble lymphangitic sporotrichosis

Primary cutaneous nocardia infections

Chromoblastomycosis

ChromoblastomycosisChromomycosis Verrucous dermatitis

A chronic fungal infection of the skin and subcutaneous tissues caused by pigmented fungi, which produce thickwalled single or multicelled clusters (sclerotic or muriform bodies) in tissue

characterized by the production of slowgrowing exophytic lesions, usually on the feet and legs

Chromoblastomycosis is caused by several fungi, the most common : Phialophora verrucosa Fonsecaea pedrosoi F. compacta Cladophialophora carrionii Rare causes Rhinocladiella aquaspersa The causative fungi have been isolated from wood & soil, and the infection usually results from trauma, such as a puncture from a splinter of wood. The condition is usually found in rural communities

Soil inhabiting fungi enters hand or feet after traumaUnilateral swelling on one site of lower limb which can beOne swelling with nodules around itScaly lesionUlcerated lesionThickened skin.Secondary bacterial infection causes pus productionRecurrent infections results in fibrosis with scar formation causing lymphatic obstruction (resembles elephantiasis)

All these fungi are named according to the dominant form of conidiation

Phialophora verrucosa

Microscopy: dominant form of conidiation is the production of ask-shaped phialides with a pronounced dark collarette at the apex. These are produced laterally or terminally

hyaline thin-walled elliptical conidia are produced at the tip of the phialide in basipetal succession

Phialophora verrucosa

Fonsecaea pedrosoi

Microscopy: dominant form of conidiation is sympodial with the conidia conned to the upper part of the cell. Cladosporium type : The brown single-celled conidia are produced on short denticles and may in turn produce secondary conidia in a similar manner with disjunctor and shield cells at the confluence.Rhinocladiella type:bottle-brush conidiaPhialophora type:flask-shaped conidia with flaring conidia having a flower in vase appearance.Conidia produced by acropetal budding

Fonsecaea pedrosoi

Clinical features:The lesions are usually found on exposed sites particularly the feet, legs, arms, face and neck.

A warty papule slowly enlarges to form a hypertrophic plaque.

In some lesions, the plaque is at and expands slowly with central scarring.

The early lesion may occasionally be an ulcer. Eventually, after months or many years, large hyperkeratotic masses are formed, and these may be as large as 3 cm thick.Pseudoepitheliomatous hyperplasia(PEH)with epithelium playing a role in transepidermal elimination (TEE) of fungus, the site represented by black dots.

Secondary ulceration may occur

The lesion is usually painless unless the presence of secondary infection causes itching and pain.

Satellite lesions are produced by scratching, and there may be lymphatic spread to adjacent areas.

Haematogenous spread has occurred but is rare, and brain abscesses have been described. Secondary infection may eventually lead after several years to lymphatic stasis with the production of elephantiasis. Some forms of the infection produce psoriasiform lesions. Squamous carcinomas may develop in chronic lesions

Rhinocladiella aquaspersa

Cladosporium carrionii

Slow growing producing small, smooth or folded Dark olive black compact colonies with entire edges marginated by black submerged hyphae.

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CHROMOBLASTOMYCOSIS(Chromomycosis)DIAGNOSTICS:specimen: scrapings orbiopsy from lesionsmicroscopy: scrapings in 10%potassium hydroxide (dark,round fungus cells = scleroticbodies diagnostic)culture in Saborauds anddigests gelatin

Lab diagnosis:

Irrespective of species, the pathogen can be seen in biopsy sections as deeply pigmented, thick-walled muriform or sclerotic cells,medlar bodies,copper-penny. Occasionally, in supercial skin scrapings from the surface of the lesions, pigmented hyphae rather than sclerotic cells are seen.Multiplication in vivo is by ssion rather than budding, and this results in the production of single, two- or multiple-celled clusters giving a chest-nut appearance.

H&E stained section showing characteristic dark brown sclerotic cells which divide by binary fission and not by budding. Note all agents of chromoblastomycosis form these sclerotic bodies in tissue.

Culture:

colonies of all species are dark greygreen to black and velvety or downy, with a black reverse.

Three forms of conidial production are observed in the most common agents of infection: acropetal budding production of phialides sympodial conidiation

Treatment:

Itraconazole (100200 mg daily) or terbinane (250 mg daily) is often successful, although responses to both are thought to be better if the causative organism is C. carrionii .

Flucytosine used on its own or combined with amphotericin B may also be effective, but resistance to ucytosine may develop if used alone

Other approaches to treatment: cryotherapy or the local application of heat

The use of surgery is contentious; in larger plaques there is a risk in pursuing this approach as satellite lesions may develop around the excision site

Surgery is really only indicated in very small lesions combined with chemotherapy.

Differential diagnosis: blastomycosis (by the absence of a sharp border containing minute abscesses and also the absence of pulmonary lesions ) cutaneous tuberculosis leishmaniasis syphilis yaws

Pheohyphomycosis

PhaeohyphomycosisA mycotic infection of humans and lower animals caused by a number of dematiaceous (brown-pigmented) fungi where the tissue morphology of the causative organism is mycelial. This 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). Clinical forms of the disease range from localized superficial infections of the stratum corneum (tinea nigra) to subcutaneous cysts (phaeomycotic cyst) to invasion of the brain.Distribution: World-wide.

Etiological agents:Wangiella dermatitidisExophiala jeanselmeiCladophilophora bantianaNattrassia mangiferaeAlternaria speciesUlocladium speciesBipolaris speciesChaetomium speciesCurvularia speciesExserohilum speciesOchrochonis gallopavum

Muriform macroconidiaAlternaria speciesUlocladium speciesEpicoccum speciesMacroconidia with transverse septaeCurvularia speciesDrechslera Ochrochonis gallopavumMicroconidiaCladophilophora bantianaWangiella dermatitidis

Clinical formsCutaneous phaeohyphomycosisSubcutaneous phaeohyphomycosisInvasive and cerebral phaeohyphomycosis - Cladophilophora bantiana4. Paranasal sinus phaeohyphomycosis

. Alternaria sp. colonizing a tomato showing typical darkly pigmented (dematiaceous) lesions.

97399. Alternaria sp. colonizing a tomato showing typical darkly pigmented (dematiaceous) lesions.

Clinical slide showing cutaneous phaeohyphomycosis of the face caused by Wangiella dermatitidis

98400.Clinical slide showing cutaneous phaeohyphomycosis of the face caused by Wangiella dermatitidis. (Courtesy of Dr. J.W. Rippon, University of Chicago, USA).

Clinical slide showing cutaneous phaeohyphomycosis of the forearm caused by Exophiala jeanselmei

99401. Clinical slide showing cutaneous phaeohyphomycosis of the forearm caused by Exophiala jeanselmei. (Courtesy of Dr. J.W. Rippon, University of Chicago, USA).

Clinical slide of subcutaneous phaeohyphomycosis following a non-penetrating injury. The lesion, on the dorsum of the right thumb, was fluctuant, tender, blue-grey and had no connection to the surface. Wangiella dermatitidis was isolated

100402. Clinical slide of subcutaneous phaeohyphomycosis following a non-penetrating injury. The lesion, on the dorsum of the right thumb, was fluctuant, tender, blue-grey and had no connection to the surface. Wangiella dermatitidis was isolated. (Courtesy of Dr. J.W. Rippon, University of Chicago, USA).

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Phaeohyphomycosis - Periodic Acid-Schiff (PAS) stained smear of pus from a subcutaneous abscess of the toe showing septate hyphal elements of Exophiala moniliae

101403. Phaeohyphomycosis - Periodic Acid-Schiff (PAS) stained smear of pus from a subcutaneous abscess of the toe showing septate hyphal elements of Exophiala moniliae.

. Exophiala jeanselmei on Sabouraud's dextrose agar showing black mucoid, yeast-like streaked colonies producing, with age, greenish-grey suede-like aerial mycelium. Reverse is olivaceous-black

102404. Exophiala jeanselmei on Sabouraud's dextrose agar showing black mucoid, yeast-like streaked colonies producing, with age, greenish-grey suede-like aerial mycelium. Reverse is olivaceous-black.

Microscopic morphology of Exophiala jeanselmei. Numerous ellipsoidal, yeast-like, budding cells are usually present, especially in young cultures. 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 (slide 405

103405. Microscopic morphology of Exophiala jeanselmei. Numerous ellipsoidal, yeast-like, budding cells are usually present, especially in young cultures. 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 (slide 405). 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 (slides 406 and 407). Conidiogenous pegs are 1-2 (-3) um long, slightly tapering and imperceptibly annellate (slides 406 and 407). Conidia are hyaline, smooth, thin-walled, broadly ellipsoidal, 3.2 - 4.4 x l.2 - 2.2 um and with inconspicuous basal scars (slide 406).

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 1-2 (-3) um long, slightly tapering and imperceptibly annellate (slides 406 and 407). Conidia are hyaline, smooth, thin-walled, broadly ellipsoidal, 3.2 - 4.4 x l.2 - 2.2 um and with inconspicuous basal scars

104406. Microscopic morphology of Exophiala jeanselmei. Numerous ellipsoidal, yeast-like, budding cells are usually present, especially in young cultures. 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 (slide 405). 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 (slides 406 and 407). Conidiogenous pegs are 1-2 (-3) um long, slightly tapering and imperceptibly annellate (slides 406 and 407). Conidia are hyaline, smooth, thin-walled, broadly ellipsoidal, 3.2 - 4.4 x l.2 - 2.2 um and with inconspicuous basal scars (slide 406).

Microscopic morphology of Exophiala spinifera showing pigmented spine-like conidiophores and clusters of single-celled annelloconidia produced in basipetal succession from an annellide.

105408. Microscopic morphology of Exophiala spinifera showing pigmented spine-like conidiophores and clusters of single-celled annelloconidia produced in basipetal succession from an annellide.

Microscopic morphology of Cladophialophora bantiana (= Xylohypha bantiana) showing conidia formed in long, sparsely branched, flexuous, acropetal chains from undifferentiated conidiophores. Conidia are one-celled (very occasionally two-celled), pale brown, smooth-walled, ellipsoid to oblong-ellipsoid and are 2-3 x 4-7 um in size. Cladophialophora bantiana may be distinguished from Cladosporium species by the absence of conidia with distinctly pigmented hila, the absence of characteristic shield cells and by growth at 42oC (compared with Cladophialophora carrionii which has a maximum growth temperature of 35-36oC and Cladosporium species which have a maximum of less than 35oC.

106409. Microscopic morphology of Cladophialophora bantiana (= Xylohypha bantiana) showing conidia formed in long, sparsely branched, flexuous, acropetal chains from undifferentiated conidiophores. Conidia are one-celled (very occasionally two-celled), pale brown, smooth-walled, ellipsoid to oblong-ellipsoid and are 2-3 x 4-7 um in size. Cladophialophora bantiana may be distinguished from Cladosporium species by the absence of conidia with distinctly pigmented hila, the absence of characteristic shield cells and by growth at 42oC (compared with Cladophialophora carrionii which has a maximum growth temperature of 35-36oC and Cladosporium species which have a maximum of less than 35oC.

Microscopy morphology of Cladosporium cladosporioides branching chains of single-celled conidia (ameroconidia) produced in an acropetal manner from simple erect, pigmented conidiophores. The term blastocatenate is often used to describe chains of conidia where the youngest conidium is at the apical or distal end of the chain. Conidia are pale brown to dark brown and have a distinct dark hilum. the conidia closest to the conidiophore, and where the chains branch, are usually "shield-shaped". The presence of shield-shaped conidia, a distinct hilum, and chains of conidia that readily disarticulate, are diagnostic for the genus Cladosporium.

107410. Microscopy morphology of Cladosporium cladosporioides showing branching chains of single-celled conidia (ameroconidia) produced in an acropetal manner from simple erect, pigmented conidiophores. The term blastocatenate is often used to describe chains of conidia where the youngest conidium is at the apical or distal end of the chain. Conidia are pale brown to dark brown and have a distinct dark hilum. Note the conidia closest to the conidiophore, and where the chains branch, are usually "shield-shaped". The presence of shield-shaped conidia, a distinct hilum, and chains of conidia that readily disarticulate, are diagnostic for the genus Cladosporium.

Microscopy morphology of a Phialophora sp. showing clusters of single-celled phialoconidia (ameroconidia) produced in basipetal succession from a phialide. conidia are not formed in chains but aggregate in slimy heads at the apices of the phialides, which show distinctive collarettes.

108411. Microscopy morphology of a Phialophora sp. showing clusters of single-celled phialoconidia (ameroconidia) produced in basipetal succession from a phialide. Note conidia are not formed in chains but aggregate in slimy heads at the apices of the phialides, which show distinctive collarettes.

Microscopic morphology of Wangiella dermatitidis showing flask-shaped to cylindrical phialides without distinctive collarettes. Conidia are hyaline to pale brown, one-celled, round to obovoid, 2.0-4.0 x 2.5-6.0 um smooth-walled and accumulate in slimy balls (glioconidia) at the apices of the phialides or down their sides. Cultures grow at 42oC

109412. Microscopic morphology of Wangiella dermatitidis showing flask-shaped to cylindrical phialides without distinctive collarettes. Conidia are hyaline to pale brown, one-celled, round to obovoid, 2.0-4.0 x 2.5-6.0 um smooth-walled and accumulate in slimy balls (glioconidia) at the apices of the phialides or down their sides. Cultures grow at 42oC

Microscopic morphology of Epicoccum nigrum showing a cluster of darkly pigmented (phaeo), globose to pyriform, rough walled multicellular conidia (dictyoconidia). Conidia are formed holoblastically on nonspecialized, determinant, slightly pigmented conidiophores, which are grouped in aggregates called sporodochia.

110413. Microscopic morphology of Epicoccum nigrum showing a cluster of darkly pigmented (phaeo), globose to pyriform, rough walled multicellular conidia (dictyoconidia). Conidia are formed holoblastically on nonspecialized, determinant, slightly pigmented conidiophores, which are grouped in aggregates called sporodochia.

Microscopic morphology of a Stemphylium sp. showing solitary, darkly pigmented (phaeo), terminal, multicellular conidia (dictyoconidia) formed on a distinctive conidiophore with a darker terminal swelling.The conidiophore proliferates percurrently through the scar where the terminal conidium (poroconidium) was formed. Stemphylium should not be confused with Ulocladium, which produces similar dictyoconidia from a sympodial conidiophore, not from a percurrent conidiogenous cell as in Stemphylium.

111414. Microscopic morphology of a Stemphylium sp. showing solitary, darkly pigmented (phaeo), terminal, multicellular conidia (dictyoconidia) formed on a distinctive conidiophore with a darker terminal swelling. Note the conidiophore proliferates percurrently through the scar where the terminal conidium (poroconidium) was formed. Stemphylium should not be confused with Ulocladium, which produces similar dictyoconidia from a sympodial conidiophore, not from a percurrent conidiogenous cell as in Stemphylium.

Ulocladium sp. Colonies are rapid growing, brown to olivaceous-black or greyish and suede-like to floccose. Microscopically, numerous, usually solitary, multicelled conidia (dictyoconidia) are formed through a pore (poroconidia) by a sympodially elongating geniculate conidiophore. Conidia are typically obovoid (narrowest at the base), dark brown and often rough-walled. Seven species have been described all being saprophytes.

112415. Ulocladium sp. Colonies are rapid growing, brown to olivaceous-black or greyish and suede-like to floccose. Microscopically, numerous, usually solitary, multicelled conidia (dictyoconidia) are formed through a pore (poroconidia) by a sympodially elongating geniculate conidiophore. Conidia are typically obovoid (narrowest at the base), dark brown and often rough-walled. Seven species have been described all being saprophytes.

Microscopic morphology of Bipolaris australiensis (= Drechslera australiensis) showing sympodial development of darkly pigmented, multicellular conidia (phragmoconidia) on a geniculate or zig-zag rachis. Conidia are produced through pores in the conidiophore wall (poroconidia) and are fusiform to ellipsoidal, germinating only from the ends (bipolar). The genera Drechslera, Bipolaris, Curvularia and Exserohilum are all closely related.

113416. Microscopic morphology of Bipolaris australiensis (= Drechslera australiensis) showing sympodial development of darkly pigmented, multicellular conidia (phragmoconidia) on a geniculate or zig-zag rachis. Conidia are produced through pores in the conidiophore wall (poroconidia) and are fusiform to ellipsoidal, germinating only from the ends (bipolar). The genera Drechslera, Bipolaris, Curvularia and Exserohilum are all closely related.

. Microscopic morphology of Exserohilum sp. Conidia are straight, curved or slightly bent, ellipsoidal to fusiform and are formed apically through a pore (poroconidia) on a sympodially elongating geniculate conidiophore. Conidia have a strongly protruding, truncate hilum and the septum above the hilum is usually thickened and dark. The end cells are often paler than the other cells and the walls are often finely roughened. Conidial germination is bipolar.

114418. Microscopic morphology of Exserohilum sp. Conidia are straight, curved or slightly bent, ellipsoidal to fusiform and are formed apically through a pore (poroconidia) on a sympodially elongating geniculate conidiophore. Conidia have a strongly protruding, truncate hilum and the septum above the hilum is usually thickened and dark. The end cells are often paler than the other cells and the walls are often finely roughened. Conidial germination is bipolar. The genus Exserohilum may be differentiated from the closely related genera Bipolaris and Drechslera by forming conidia with a strongly protruding truncate hilum (i.e. exserted hilum). The hilum is defined as "a scar on a conidium at the point of attachment to the conidiophore". In Drechslera species, the hilum does not protrude whereas in Bipolaris species the hilum protrudes only slightly.

The genus Exserohilum may be differentiated from the closely related genera Bipolaris and Drechslera by forming conidia with a strongly protruding truncate hilum (i.e. exserted hilum). The hilum is defined as "a scar on a conidium at the point of attachment to the conidiophore". In Drechslera species, the hilum does not protrude whereas in Bipolaris species the hilum protrudes only slightly.

115419. Microscopic morphology of Exserohilum sp. Conidia are straight, curved or slightly bent, ellipsoidal to fusiform and are formed apically through a pore (poroconidia) on a sympodially elongating geniculate conidiophore. Conidia have a strongly protruding, truncate hilum and the septum above the hilum is usually thickened and dark. The end cells are often paler than the other cells and the walls are often finely roughened. Conidial germination is bipolar. The genus Exserohilum may be differentiated from the closely related genera Bipolaris and Drechslera by forming conidia with a strongly protruding truncate hilum (i.e. exserted hilum). The hilum is defined as "a scar on a conidium at the point of attachment to the conidiophore". In Drechslera species, the hilum does not protrude whereas in Bipolaris species the hilum protrudes only slightly.

Microscopic morphology of Veronaea botryose. Conidiophores are erect, straight or flexuose, occasionally branched and are usually geniculate, due to the sympodial development of the conidia. Conidia are pale brown, 2-celled, cylindrical with a truncated base, smooth-walled or slightly verrucose [5-12 X 3-4 um].

116420. Microscopic morphology of Veronaea botryose. Conidiophores are erect, straight or flexuose, occasionally branched and are usually geniculate, due to the sympodial development of the conidia. Conidia are pale brown, 2-celled, cylindrical with a truncated base, smooth-walled or slightly verrucose [5-12 X 3-4 um].

Microscopic morphology of Pithomyces chartarum showing darkly pigmented, multicellular conidia (phragmo- or dictyoconidia) formed on small peg-like branches of the vegetative hyphae. Conidia are broadly elliptical, pyriform, oblong, and commonly echinulate or verrucose. Pithomyces chartarum is often involved with facial eczema of sheep.

117421. Microscopic morphology of Pithomyces chartarum showing darkly pigmented, multicellular conidia (phragmo- or dictyoconidia) formed on small peg-like branches of the vegetative hyphae. Conidia are broadly elliptical, pyriform, oblong, and commonly echinulate or verrucose. Pithomyces chartarum is often involved with facial eczema of sheep.

Microscopic morphology of Aureobasidium pullulans showing chains of 1- to 2-celled, darkly pigmented arthroconidia commonly called chlamydoconidia. These arthroconidia actually represent the Scytalidium anamorph of Aureobasidium and are only of secondary importance in recognizing members of this genus. Presence of hyaline, septate hyphae, some undergoing holothallic transformation to arthroconidia, giving rise to numerous hyaline, single-celled, ovoid-shaped conidia (ameroconidia) which are produced on short denticles.

118422. Microscopic morphology of Aureobasidium pullulans showing chains of 1- to 2-celled, darkly pigmented arthroconidia commonly called chlamydoconidia. These arthroconidia actually represent the Scytalidium anamorph of Aureobasidium and are only of secondary importance in recognizing members of this genus. Also note the presence of hyaline, septate hyphae, some undergoing holothallic transformation to arthroconidia, giving rise to numerous hyaline, single-celled, ovoid-shaped conidia (ameroconidia) which are produced on short denticles.

Microscopic morphology of the Scytalidium anamorph of the Coelomycete Hendersonula toruloidea showing chains of 1- to 2-celled, darkly pigmented arthroconidia produced by the holothallic fragmentation of undifferentiated hyphae. Hendersonula toruloidea is a recognized agent of onychomycosis and superficial skin infections, especially in tropical regions.

119423. Microscopic morphology of the Scytalidium anamorph of the Coelomycete Hendersonula toruloidea showing chains of 1- to 2-celled, darkly pigmented arthroconidia produced by the holothallic fragmentation of undifferentiated hyphae. Hendersonula toruloidea is a recognized agent of onychomycosis and superficial skin infections, especially in tropical regions.

RhinophycomycosisSlow progressing infection of subcutaneous tisssues or paranasal sinuses Causative agent- Conidiobolus coronatusSaprophyte in soil humus and decomposing plant matterInhalation of spore or implantation of spores into nasal cavities by fingernails Older age group

Affects the nasal mucosa of the turbinates and spreads to the subcutaneous tissues of the face and neck facial deformities with large nosePainless, hard swelling+/- nasal obstruction, +/- epistaxisPain on secondary bacterial infections.Treatment- Itraconazole, Ketoconazole, fluconazole, amphotericin B, Potassium iodide

Rhinosporidiosis

This is a chronic granulomatous disease characterised by the development of friable polyps, usually confined to the nose, mouth or eye but rarely seen on the genitalia or other mucous membranes

Distribution

Although the disesase was first identified in Argentina, most cases come from India and Srilanka

Causative agent: Rhinosporidium seeberi

R. seeberi cannot be cultured in cell-free artifical media

Aimal inoculation is also not successful

Pathogenesis and clinical features

The mode of infection of this fungus is not known

However, it is suggested that it is transmitted in dust and water

Fish is believed to be the natural host of this fungus

Infection is seen most commonly in persons taking bath in stagnant pools and in individuals who dive in streams to collect sand from river beds

The disease is characterized by the development of large friable polyps or wart-like lesion in the nose, conjunctiva or eye

The lesions can also be seen in buccal cavity, skin or genitalia

Laboratory diagnosis

Depends on demonstration of sporangia of R. seeberi in tissue sections stained with H & E or other special stains such as GMS stain and PAS stain

The sporangia measure 10-200 m in diameter and contain thousands of endospores

H&E stainEndospores and sporangia of Rhinosporidium seeberi

Treatment

Treatment of the condition is carried out by surgery or cauterization

Chemotherapy with dapsone is also useful

LOBOMYCOSIS

Lobomycosis.Lobomycosis is a chronic, localized, subepidermal infection characterized by the presence of keloidal, verrucoid, nodular lesions or sometimes by vegetating crusty plaques and tumors. The lesions contain masses of spheroidal, yeast-like organisms tentatively referred to as Loboa loboi. There is no systemic spread. The disease has been found in humans and dolphins and is restricted to the Amazon Valley in Brazil. The aetiologic agent known as "Loboa loboi" remains to be cultured. It typically effects the exposed areas of the skin and the extremities.

Lobomycosis showing extensive verrucoid lesions on the legs. The initial infection is thought to be caused by traumatic implantation such as an arthropod sting, snake bite, sting-ray sting, or wound acquired while cutting vegetation. 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. Older lesions become verrucoid and may ulcerate.

131348.Lobomycosis showing extensive verrucoid lesions on the legs. The initial infection is thought to be caused by traumatic implantation such as an arthropod sting, snake bite, sting-ray sting, or wound acquired while cutting vegetation. 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. Older lesions become verrucoid and may ulcerate. The disease may be transferred to other areas of the skin by further trauma or autoinoculation. Thus the areas of involvement may become quite extensive. Lesions are usually found on the arms, legs, face or ears. 90% of cases are men, mostly in farmers and other high-risk groups exposed to various harsh conditions as well as aquatic habitats.

Grocotts 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. The disease may be transferred to other areas of the skin by further trauma or autoinoculation. Thus the areas of involvement may become quite extensive. Lesions are usually found on the arms, legs, face or ears. 90% of cases are men, mostly in farmers and other high-risk groups exposed to various harsh conditions as well as aquatic habitats.

132349. Grocotts 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.

Virulence Factors: Does not become a systemic fungal infection, but fungalcells can be found in proximal lymph nodes.Epidemiology and Ecology Effects immunocompetent patients Wide distribution in South America Isolated cases in the United States, Canada, and inEurope More common in men (68-92% of cases) than in women Average age of infected patient: 38 years old

Forms of the disease Cutaneous lobomycosis Subcutaneous lobomycosisCutaneous Lobomycosis Shiny, atrophic, and discoloured skin Lesions, papules, or plaques that are verrucoid and orulcerative Lesions usually found on the arms, legs, face, or ears Lesions are typically burn and/or itchCollections of tissue samples

Diagnosis :-Tissue samples are typically obtained by curettage orsurgical biopsyHistopathology Tissue Stains 10% KOH and Parker Ink Gomori Methenamine silver stain Periodic acid-Schiff stain(all used to demonstrate the yeast-like cells)

Identification Slow growing fungi Most likely reproduces through budding Spherical intracellular yeast that are remarkablyhomogenous Darkly pigmented fungal cells when GMS is used forstaining

Treatment and Prevention Requires Early diagnosis Surgical excision Oral clofazimine therapy There is no current method known for preventinglobomycosis

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