Opportunist

• cause disease in people who are immunocompromised

Endogenous opportunist

Candida albicans

Morphology: yeast(blastospore), pseudohyphae(like links), true hyphae (have septa, paralel walls)

Candida albicans in rabbit kidney

very light stain

Candida albican in liver

Candida albican

this is a culture (most likely not tested)

Candida albican Chlamydospores

in starvation medium "corn meal agar test"

Candida albicans in sputum

over decolorized slide

Rhizopus in tissue

wide nonseptate hyphae

irregualr branching (90 deg)

Rhizopus in kidney

wide nonseptate hyphae

irregular branching

Pneumocystis carinii

cause pneumonia in AIDS patients

note the brown red blood cells

Pneumocystis carinii

Cryptocossus neoformans in tissue

has fuzzy coloring capsule

barrow base buddings

Extracellular

Mating type a & alpha

haploid dominant

Serotype: D (found in Europe) associate with AIDS& children in NYC

Systemic fungi

• normal habitat: soil
• can cause pulmonary infection when inhaled

Blastomyces dermatitidis

Blastomyces dermatitidis tissue section

Blastomyces dermatidis mycelial phase

Conidia wider than pointer 4-5 micrometer

Blastomyces dermatitidis yeast phase (lactophenol blue wet mount)

Yeast wider than pointer 8-20 micrometer

Blastomyces dermatitidis tissue section (Gomori silver stain)

yeast wider than pointer (8-20 micrometer)

Histoplasma capsulatum

Histoplasma capsulation in brain tissue (Gomoro stain)
Magnification 100X

Histoplasma capsulatum in tissue

100X

Histoplasma capsulatum mycelial phase (slide culture wet mount)
8-20micrometer, 400X
note the spiky conidia

Paracoccidioides brasiliensis 

No sexual phase

37 deg C: multiple buds yeast with narrow bases (multinucleate, need sulfur containing aminoa acid)

Disease: Lesions [due to conidia inhalation]

Subclinical (no symptom just flu, nodules & plaques)

Chronic unifocal (adult smoker, whose 1 lung infected)

Chronic multifocal (resemble TB, cough, chest pain, weight loss)

Subjuvenile

AIDS

Distribution:

South, Central America

humid Summer & dry Winter

Rural>>Urban

Clinical disease M>>F

-Estrogen inhibit tranformation of Y to H

-Estrogen bing protein found in cytoplasm

Diagnose:

Skin test

Serological test

 Paracoccidioides brasiliensis yeast phase (lactophenol blue wet mount)
10-60 micrometer
multiple buds with narrow bases

Paracoccidiodes brasiliensis tissue section (Gomori stain)

multiple buds with narrow bases

Agents that cause Mycetoma

granule from Mycetoma (Madura foot)

causative agent: fungus

Coccidiodes immitis

"immitis" = not mild, severe biohazard

18S rRNA
25 deg C: septate hyphae & alternating arthroconidia with disjunctions that lyse [saprophytic that ruptures with wind]

37 deg C: slimy polysaccharide, yeast with large endospores [in host]

Habitat: alkali soil, arid climate (southern Arizona, central California, Southern New Mexico, & west Texas)

Disease: MOST DANGEROUS SYSTEMIC MYCOSES

Acute Coccidiodomycetoma [inhaling the arthroconidia, effect ppl with low immune system]

-endospores germinate in the lungs (rare, but lethal)

-erythema nodusum (red infected lumps)

-Adult M> Adult F (hormomal control)

Chronic cutaneous Coccidiodomycosis

-High risk for: HIV patients, organ transplant, pregnant woman (hormone)

Diagnose:

Skin test

Serological test

Microscopy

Coccidiodes immitis sperule

note the large endospores

Coccidiodes immitis sperule in human lung tissue (Gomori silver stain)

humungus endospores

Coccidioides immitis sperule (KOH mount)

spot the endospore

Artifact: this is fat globule that can be mistaken for sperule or yeast.

Geotrichum mycelia (lactophenol blue wet mount)

Coccidiodes immitis mycelial phase (Lactophenol blue wet mount)

Sporothrix schenckii

• dimorphic
• 22 deg C: fine septate hyphae with cluster of conidia
• 37deg C: elongated yeast cells with cigar-shaped buds (the form when they infect tissues)

Habitat: soil, animal excreta, living or decaying vegetative
Disease: Sporotrichosis [caused by animal bites, rose thorns, insect sting...]
-papule enlarges overdays or weeks
-can persist for years
-does not cure without treatment
-erythematous(redness from inflamation), ulcerated, pus

Sporothrix schenckii yeast phase from a laboratory mouse
smaller than pointer 1-3 micrometer
look for cigar shaped yeast

Sporothrix schenckii yeast phase lactophenol blue wet mount

look for cigar shaped yeast

Sporothrix schenckii mycelial phase (stain of slide culture)

very fine, delicate

smaller than pointer

...

Scopulariopsis spp.geicohands-like conidiophore

large, rough, annelloconidia (produced by annelides)

Aspergillus spp.

Conidiophores with phialoconidia

brush like

similar with Penicillium but has more volume & shorter conidia

Superficial Mycoses

1. Disease:

• Pityriasis versicolor (patches altered pigment, versicolor & scaling)
• Seborrhoeic dermatitis (includes Follicular pityriasis & Dandruff)

causative agent: Malassezia furfur

hyphae & yeast (spaghetti & meat balls)

Basidiomycete

Lipophilic yeast (loves fat/lipid)

can be systemic => nutritional, supplementation, associate with catheters  

1. Tinea nigra
• causative agent: Exophiala wernekii (dimorphic, Ascomycete, yeast in culture; mold in lession)
• form brown to black spots
• tropical disease
• palm & soles
• young F>M 
2. Piedra: infect hair, formation of waxy small, firm masses on hair
• Black
• black nodules on scalp
• causative agent: Piedraia hortae ()
• tropical, M>F (swimmers)
• White
• white nodules on beard, mustache, genital region
• causative agent: Trichosporon beigelii (mold, septate, hyphae)
• temperate & tropical, south US, M>F

Dermatophytes (skin infection)

• Trichophyton
• Microsporum
• Edidermophyton

All molds, septate hyphae
30-70% adults
incident increase with age

Techniques, Sapprophyte

Sexual stages of 3 classes:

Basidiomycetes

brown basidiospore

Zygomycetes

dark colored zygospore formed from fusion of 2 aseptate hyphae

Ascomycetes

the 2 celled ascospores are produced in a sac like ascus

Dermatophytes and other fungi that causes superficial infections:

limited to keratinized tissues. ie. skin, hair, nails

dermatophyte infection determined by observing skin scrapping in KOH wet mount

has macroconidia & microconidia

Microsporum canis

spindle-shaped, thick walled macroconidia.

has up to 15 septa.

Microsporum gypseum

thin wall
usually 4-6 septa

Epidermophyton floccosum

club-shaped macroconidia
2-3 septa
no microconidia

Tricophyton mentagrophytes
cigar-shaped
thin walled macroconidia
abundant
coiled hyphae
hair perforation positive

Tricophyton rubrum
cigar-shaped macroconidia
thin walled microconidia
Dermatophyte
anthropophillic (attracted to man*), zoophillic, geophillic [as pop. decrease, lose ability to mate]

Saprophytes: Organisms that live on dead organic matter

Aspergillus

chained conidia on phialides arise from swollen vesicle

Exogenous opportunistic fungus.

Scopulariopsis spp.

geicohands-like conidiophore

large, rough, annelloconidia (produced by annelides)

Penicillium

chains of conidia from branched conidiaphore

brush like, longer than Aspergillus

Penicillium marnefei

severe biohazard

intracellular (Histo too!!)

dimorphic

haploid, no sexual stage

most infected by HIV positive patients

Disease:(by inhalation)

once infected, cannot be cured

effect immune surpress individuals (ie. HIV)

Disribution:

Southeast Asia, nothern Thailand

Diagnose:

Culture, PCR, Serological test

Rhizopus

non-septate, wide hyphae

sporangia filled with sporangiospores

has rhizoids at base of sporangiophore

Rndogenous opportunistic fungi

Mucor

septate hyphae
sporangiospores in sporangia.

Alternaria

dematiaceous (dark colored)

club-shaped conidia