Fungus Reservoir Morphology Microscopic Clinical Image Diagnosis Treatment Miscellaneous Su

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Malassezia sp. M. furfur M. pachydermatis

Warm moist/humid environments “Sweaty workers in the sun outside”

Yeast clusters & short curved non-branching septate hyphae “spaghetti & meatballs”

“bacon & eggs”

Pityriasis versicolor/ Tinea flava Hypo/hyperpigmented sports on trunk, blotchy suntan Pityriasis folliculitis on sun

exposure MCC dandruff & Seborrhoeic dermatitis on scalp, face, trunk

KOH mount of skin scrapings Coppery-orange fluorescence under

wood lamp (UV) Sabouraud’s + olive oil or Dixon’s agar

Topical selenium sulfide in dandruff shampoo Topical imidazole

(ketoconazole) in shampoo

Lipophilic yeast requires fat. Thus grow near sebaceous glands on skin

Fungemia in premature infants on intravenous lipid supplements

Hortaea werneckii

(formally Exophiala werneckii)

Tropical: central,

south America or Asia & Africa Saprophytic fungus in soil

Brown pigmented branched

septate hyphae and buddying yeast

Tinea nigra

brown to black non-scaly painless macules often on the palms of hands or soles of feet resembles a silver-nitrate stain

KOH mount of skin

scrapings Sabouraud’s agar

Topical selenium

sulfide in dandruff shampoo Topical imidazole (ketoconazole) in shampoo

Brown pigment

because of melanin production in cell wall

Trichosporon beigelii

Irregular, soft, white or light brown nodules, 1.0-1.5 mm in length, firmly adhering to the hairs

White piedra Epilated hairs with white soft nodules present on the shaft

Mainly on axilla, scalp, facial or pubic hair

KOH Sabouraud’s agar

Shaving Topical imidazole

the nodules are easily detached from the hair shaft by rubbing along its length

Piedra iahortae

Black piedra Brown to black nodules will be

firmly adherent to the shaft and cannot be readily detached

KOH Sabouraud’s agar

Shaving Topical imidazole

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Dermatophytes

Trichophyton sp. (hair, skin, nail) Microsporum sp. (hair, skin) Epidermophyton

floccosum (skin, nail)

Human infected skin

scales primarily from foot Skin shedding on carped, soil

Typical dermatophyte hyphae

breaking up into arthroconidia “Tinea” b/c ringworm like appearance

Tinea corporis (body) glabrous skin

Tinea cruris (pubic) “jock itch” Tinea pedis (foot) “athlete’s foot” Tinea unguium (nails) Onychomycosis Tinea barbae (beard) Tinea capitis (scalp) - ectothrix: outside hair shaft - endothrix: invasive in hair shaft

- favus: cup-shaped crusts (scutula) > kerion (inflammatory response)

KOH

Sabouraud’s agar

Terbinafine

Topical imidazole

Keratinase helps

digest keratin in cutaneous skin Tinea favus of the scalp is highly contagious and causes permanent baldness.

Candida albicans

Sub

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Sporothrix schenckii Soil, plants, “rose

thorns”

Dimorphic

@ 25*C Hyphae with rosettes & sleeves of conidia @ 37*C Cigar shaped/ small narrow base budding yeast in tissue

“Rose handler’s disease”

Lymphocutaneous sporotrichosis Painless nodule > necrotic + exudate > progression to proximal nodules along lymph channels Pulmonary sporotrichosis cough > hemoptysis > death

KOH

Sabouraud’s agar In tissue: PAS GMS stain ( Grocott's methenamine silver, GMS)

Potassium iodide

Itraconazole Amphotericin B

Phialophora verrucosa Fonsecaea pedrosoi Cladophialophora carrionii

Rotting wood Brown pigmented/ copper colored, planate-dividing, rounded sclerotic bodies Saprophytic

Chromoblastomycosis Painless scaly papules > raised irregular plaques, verrucose (wart like) > cauliflower like tumorous, epithelial hyperplasia, fibrosis, & mircoabscesses

KOH Sabouraud’s agar In tissue: PAS GMS

Itraconazole Flucytosine Surgical

Lacazia loboi

(formerly named Loboa loboi)

Latin America, Brazil chains of darkly pigmented,

spheroidal, yeast-like organisms

Lobomycosis

Hard nodules resembling keloids can spread Lesions are usually found on the arms, legs, face or ears

KOH

Sabouraud’s agar In tissue: PAS GMS

Surgery traumatic

implantation such as an arthropod sting, snake bite, sting-ray sting, or wound acquired while cutting vegetation

Syst

emic

Blastomyces dermatitidis

Soil & rotting wood eg. beaver dams Ohio, Mississippi river valley extending north

to Great Lakes, Minnesota, Canada

Dimorphic @ 25*C Mycelial form, hyphae with nondescript conidia @ 37*C

large, broad-base, unipolar budding yeast-like cells, refractile thick cell walls

Blastomycosis Inhalation of spores > asymptomatic or pneumonia > cutaneous spread to face, scalp,

upper body with irregular verrucous ulcers > osteoarticular spread to spine, pelvis, ribs

KOH Sabouraud’s agar Lung biopsy: PAS

GSM

Ketoconazole Amphotericin B

Hardest to acquire infection but when acquired leads to severe disease

Histoplasma capsulatum

Ohio Mississippi river valley

Soil enriched with bat & bird droppings Cave exploring Chicken coops

Dimorphic @ 25*C

Tuberculate macroconidia and small microconidia with hyphae @37*C small narrow base budding yeast cells (1-5um diam) inside macrophages

Histoplasmosis Inhalation of spores

95% asymptomatic Tuberculosis like disease spread Calcified lesions on chest X-ray Disseminated mucocutaneous lesions common +/- Hepatosplenomegaly

KOH Sabouraud’s agar

Lung biopsy: PAS GSM

Itraconazole Amphotericin B

Facultative intracellular parasite found in

reticuloendothelial cells (RES)

Coccidioides immitis Southwestern US ( San Joaquin valley, Arizona, New Mexico, Nevada, Texas)

Dessert sand

Dimorphic @ 25*C Hyphae breaking up into arthroconidia

@ 37*C Spherules with endospores +/- prominent thick cell wall

Coccidioidomycosis “Valley fever” Inhalation of spores > Calcified pulmonary lesions as they heal, self-limiting pneumonia >

Desert bumps (erythema nodosum), granulomatous lesions

KOH Sabouraud’s agar Lung biopsy: PAS

GSM

Amphotericin B Pregnant females in third trimester or AIDS patient increased chance of dissemination from

initial disease

Cryptococcus

neoformans

Soil enriched with

pigeon droppings

Polysaccharide capsule

Globose to ovoid budding yeast-like cells Urease positive

Cryptococcosis

Pulmonary: self-limiting pneumonia Disseminated: Brain most commonly, causing meningitis or rarely cryptococcoma Skin nodular ulcerated acne like lesions

KOH + India ink (

50% miss) Confirm with Latex particle agglutination for capsule

Amphotericin B +

Flucytosine

MCC of meningitis in

Hodgkin’s/AIDS patients

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Aspergillus fumigatus A. flavus A. niger

Everywhere Common contaminant

Dichotomously acute angled branched, septate hyphae and a conidial head

Aspergillosis Pulmonary: Allergy/asthma exacerbation Aspergilloma (fungus ball) in preformed lung cavities > hemoptysis

Invasive: neutropenic, leukemic, CGD, CF, & burn unit patients Necrotizing pneumonia spreads to to brain, kidney, bone

KOH Chest X-ray for pneumonia or aspergilloma

Surgery for aspergilloma Invasive: Amphotericin B

A. flavus secretes Aflatoxin which contimanted peanuts, grains, rice > ingestion leads to liver cancer

Candida albicans Normal flora Mucus membranes

Yeasts +/- germ tubes in serum Pseudohyphae & true hyphae when invades tissue

Candidiasis Normal host: Oral thrush, glossitis, cheilitis (perleche), diaper rash, intertrigo (inflammation in body folds) ,

vulvo-vaginitis, blanitis Immune-compromised: Esophagitis, gastritis, septicemia in AIDS Endocarditis: iv drug abuse Chronic mucocutaneous Disseminated

KOH In tissue: PAS GMS

Cutaneous and oral infections use nystatin and imidazoles

Systemic and chronic infections use amphotericin B and ketoconazole

Cottage cheese/ curdish discharge in vaginitis patients Normal host get

infections because of antibiotics use

Rhizopus Rhizomucor Mucor

Soil Non-septate thin walled hyphae with focal bulbous dilations and irregular broad angled branching

Mucormycosis Rhinocerebral (associated with diabetes): invades nasal mucosa into orbit

Pulmonary: necrosis and cavitation Gastrointestinal (malnutrition) Cutaneous (burn patients)

KOH In tissue: PAS GMS

Amphotericin B Surgery aggressive

Rapidly fatal

Pneumocystis jiroveci (formally P. carinii)

Acquired early by respiratory route Latent in normal host

Cysts in silver stained tissue Flying saucer type cysts

“PCP pneumonia” Atypical pneumonia in AIDS CD4+ < 50 Kills Type I pneumocytes causing damage to alveolar epithelium. Foamy or honeycomb appearance on H&E

Diffuse/patchy infiltrate Granular, reticular , ground glass appearance on X-ray

Silver stain the bronchoalveolar lavage fluid H&E

Trimethoprim Sulfamethoxazole Dapsone

MCC death in AIDS patients