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Types of

Mycoses

according tosite

Fungus Specimen

of Choice

Culture

Media and

InoculationConditions

Methods of

Identification

Morphology and

Microscopic

Characteristics

Treatment

Superficial

Mycoses

Piedraia hortae Hair Clippings Hair fragmentsshould beimplanted ontoprimary isolation

media, likeSabouraud'sdextrose agar.

Hair Clippingsare examinedby KOHpreparation

Green-black heapedcolonies on SDA.

Microscopic: dark,thick-walled hyphaewith swellings

Haircut-shave,improve hygiene,topical azoles (ifhygiene is notsufficient), If notcleared by hygienethen can use

Terbinafine (given6wks)

Malassezia furfur Skinscrapings

Grows onSDA with oliveoil in 2-4 daysat 30C.

Skin scrapingswith KOH

Yeast-like colonieson SDA.

Microscopic:Spaghetti withmeatballs

appearance

Selenium sulfideTopical imidazoles

Exophiala werneckii Skinscrapings

Clinicalspecimensshould beinoculated ontoprimary isolation

media, likeSabouraud'sdextrose agar.

Skin scrapingsare examinedusing 10% KOHand Parker ink orcalcofluor whitemounts.

Black yeastlycolonies with olive-green mycelium onSDA.

Microscopic: darkone to two-celledblastoconidia

Usually, topicaltreatment withWhitfield's ointment(benzoic acidcompound) or an

imidazole agent twicea day for 3-4 weeks iseffective.

Trichosporon beigelii Hair Clippings cornmeal-tween 80agar; SDAwithoutcycloheximideat roomtemperaturefor 48 hours.

Cream-colored,wrinkled colonies onSDA.

Microscopic:hyalinehyphae,blastoconidia andarthrospores whengron on cornmeal-tween 80 agar.

Haircut-shave,improve hygiene,topical azoles (ifhygiene is notsufficient.

Amphotericin,fluconazole, anditraconazole areused in treatment oftrichosporonosis


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Cutaneous

MycosesMicrosporum (M.canis,M.audouinii)

SkinscrapingsHair Clippings

Inoculation onspecificmedia, suchas potatodextrose agaror Sabouraud

dextrose agarsupplementedwith 3 to 5%sodiumchloride maybe required tostimulatemacroconidiaproduction ofsome strains.

Microscopy offungal hyphaefrom skinscrapings, hairspecimens in10% KOH

(Parkers Ink(blue),CalcofluorWhite stains);

Microsporum spp.produce septatehyphae,microaleurioconidia,andmacroaleurioconidia.

Conidiophores arehyphae-like.Microaleuriconidiaare unicellular,solitary, oval toclavate in shape,smooth, hyaline andthin-walled.Macroaleuriconidiaare hyaline,echinulate toroughened, thin- tothick-walled,typically fusiform(spindle in shape)and multicellular (2-15 cells).

ImidazoleOral griseofulvin

Trichophyton(T.mentagrophyte,

T.rubrum,T.tonsurans)

SkinScrapings

Hair ClippingsNailSpecimen

Growth onSDA

supplementedwithcycloheximide

Microscopy offungal hyphae

from skinscrapings, hairor nailspecimens in10% KOH(Parkers Ink(blue),CalcofluorWhite stains);

T.mentagrophyte:White granular and

fluffy varieties;occasional lightyellow on youngercultures.

Microscopic:microconidia appearin grapelike clusters.

ImidazoleOral griseofulvin


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along withblastoconidiaand true hyphae

Microscopic:morphology showsspherical to

subspherical buddingyeast-like cells orblastoconidia, 2.0-7.0 x3.0-8.5 um in size.

Subcutaneous

mycoses

Sporotrichosis:Sporothrix schenckii

Exudateaspiratedfromunopenedsubcutaneousnodules

Growth inSDA.

Stain sampleusing PAS.

Usually appears assmall, round to ovalcigar-shaped yeastcells. If stained withPAS, an amorphouspink material may beseen surroundingthe yeast cell.

Microscopic:Hyphae are delicate,septate andbranching.

Potassium iodide isone of the oldesttherapeuticmodalities used fortreatment ofsporotrichosis,

Amphotericin B,ketoconazole, anditraconazole arenow morecommonly used intreatmentof Sporothrixschenckii infections.

Chromoblastomycosis:

Fonsecae(F.pedrosoi,F.compacta),Phialophora(P.verrucosa)Cladosporium (C.carrionii)

Skin

scrapings

Growth on

SDAsupplementedwithcycloheximide;

Scrapings from

crusted lesionsadded to 10%potassiumhydroxide.

These fungi are slow

growing andproduce heaped-upand slightly fold,darkly pigmentedcolonies with a grayto olive to black andvelvety or suedlikeappearance.

Itraconazole +

Terbinafine

Mycetoma:

Pseudallescheria boydiiNocardia brasiliensis

Pus, exudate,

or tissue.

Specimens

containingfungi areinoculatedonto InhibitoryMould agar orBHI agar with10% sheepblood andincubated at30C. The

Acid-fast stain

is used todetect Nocardiaspp;Pus, exudate,or tissue shouldbemacroscopicallyexamined forsclerotia.Sclerotia are

P.boydii: Initial

growth begins as awhite, fluffy colonythat changes inseveral weeks tobrownish graycolony.

Mycetomas caused

by fungi are usuallyresistant tochemotherapy ,although anecdotalreports of responseto long-termtherapy withketoconazole hasbeen appeared.Surgical


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sclerotiashould bewashed insterile water orin an antibioticsolution priorto inoculation.Some fungiare sensitivetocycloheximide,thus IMA, SDA

and a mediumcontainingcycloheximideshould beused together.

mounted insterile salineand thencrushed.

Actinomycetegranules arecomposed offilaments 0.5-1.0 m indiameter as wellas coccoid andbacillary

elements.Fungal hyphaeare 2-5 m indiameter withmanyintercalaryswollen cells

debridement maybe necessary, andamputation issometimes the finalstep.

Opportunistic

systemic

mycoses

Cryptococcus neoformans This isolate isurease

positive butfails to growon mediumcontainingcycloheximideor at 40C

Colonies onSabouraud dextrose

agar at 25C arecream to beige andmucoid due to thecapsule surroundingthe yeast cells.Some a-capsularstrains have beenrecovered,particularly from HIVpatients on long-term maintenancetherapy.

On cornmealfollowing 72 hoursincubation at 25C, itproduces globoseyeast cells only (2.5-10 m in diameter).


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Aspergillus fumigatus Cultures arethermotolerantand are ableto withstandtemperaturesup to 45C.Fresh clinicalspecimens areneeded fordirectmicroscopicexamination.

Produces a fluffy togranular, white toblue-green colony,Microscopic:Characterized by thepresence of septatehyphae and short orlong conidiosporeshaving acharacteristic footcell at their base.

Azoles

Candida albicans Skinscrapings

Grown onSDA.

Microscopy offungus fromskin scrapingsin 10% KOH(H&E stain),Observe forpseudohyphaealong withblastoconidia

and true hyphae

On Sabouraud'sdextrose agar coloniesare white to creamcolored, smooth,glabrous and yeast-likein appearance.

Microscopic:morphology showsspherical to

subspherical buddingyeast-like cells orblastoconidia, 2.0-7.0 x3.0-8.5 um in size.

Topical creams(Desitin, Butt Paste)and oils

Dimorphic

systemic

mycoses

Histoplasma capsulatum SputumSpecimenfrom bonemarrow andrarelyperipheral

blood.

It isrecommendedthat thespecimen becultured assoon as

possible. It isconsidered tobe a slow-growing moldat 25C to30C andcommonlyrequires 2 to 4weeks or more

Wright-GiemsaStain.Exoantigen TestSpecific Nucleic

Acid probe

Microscopic:intracellularly withinmononuclear cellsas small, round tooval yeast cells.

Amphotericin B,itraconazole andfluconazole


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for colonies toappear.

Blastomyces dermatitidis Sputum Grown onenrichedculture media;Commonlyrequires 5days to 4weeks orlonger forgrowth to bedetected.

Exoantigen TestSpecific Nucleic

Acid probe

Microscopic:Appears as large,spherical, thick-walled yeast cellsusually with a singlebud that isconnected to aparent cell with asingle base.

Amphotericin B,ketoconazole, anditraconazole

Coccidioides immitis Sputum Strict safetyprecautionsmust befollowed whenexaminingcultures.Maturecoloniesappear within

3 to 5 days ofincubation onmost media,includingthose used inbacteriology.

Exoantigen TestSpecific Nucleic

Acid probe

Microscopic:Appears as anonbudding, thick-walled spherulecontaining eithergranular material ornumerous smallnonbuddingendospores.

Amphotericin Band azoles, such asfluconazole,itraconazole,and ketoconazole.

Paracoccidioidesbrasiliensis

Sputum,mucosalbiopsy andotherexudates

Grown onBlood-enrichedmedium.

Exoantigen Test Microscopic: Smallhyphae are seenalong with numerouschlamydoconidia.Small, delicate,globose or pyriformconidia may beseen.

Types of Mycoses According to Site

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