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Dematiaceous molds (general) - meaning, disease, habitat, classification
- mean: brown-pigmented
- disease: superficial and subcutaneous mycoses
- habitat: ubiquitous in nature (humans and animals accidental hosts)
- classification: slow growing (7-10 days) and rapid growing (<7 days)
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disease and cause - Tinea nigra, black piedra, mycetoma, chromoblastomycosis, phaeohyphomycosis
- tinea nigra: skin infection caused by Hortaea werneckii
- Black piedra: hair/scalp infection caused by Piedraia hortae
- Mycetoma: chronic granulomatous infection involving lower extremities (bacterial or fungal)
- Chromoblastomycosis: chronic infection acquired by traumatic innoculation
- lesions reveal sclerotic bodies, resemble copper pennies
- Phaeophyphomycosis: infections from brownish yeastlike cells, pseudohyphae, or hyphae
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Hortea werneckii - disease, what is found in tissue
- Tinea nigra (skin infection)
- Tissue contains hyphal fragments, budding yeast
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Piedraia hortae - disease, what is found in tissue
- Black piedra (hair infection)
- Tissue contains asci-containing nodules cemented to hair shafts
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What are the two types of fungal mycetomas? Where are they found?
- White grain and Black grain
- Infections mostly in tropical/subtropical regions w/ those who have outdoor occupations
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Pseudallescheria boydii - disease, speed, unique colony, reproduction, unique micro
- disease: White grain mycetoma
- speed: rapid
- colony: white mouse fur (reverse is brownish)
- repr: Asexual = Scedosporium apiospermum (culture-based, graphium stage)
- sexual = cleistothecia
- micro: lollipop-like
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Acremonium - disease, unique colony, unique micro
- disease: white grain mycetoma
- colony: compact/glabrous -> felt-like, pale rose
- micro: extremely delicate, septate hyphae, oblong conidia
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Curvularia - disease, unique micro
- disease: black grain mycetoma
- micro: large brown conidia, 4 cells, appear curved due to 3rd cell swelling
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Cladosporium - disease, where in tissue, unique colony, unique micro
- disease: Chromoblastomycosis (copper penny lesions)
- saprophytic contaminant
- tissue: subcutaneous tissue
- colony: greenish/brown w velvety nap, reverse is black
- micro: produce conidial chains w/ dark spots at site of attachment
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Phialophora - disease, where in tissue, unique micro
- disease: Phaeohyphoycosis
- Chromoblastomycosis (copper penny lesions)
- tissue: subcutaneous, joints
- micro: Phialides are vase shaped w/ flared cup collaretts
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Fonsecaea pedrosoi - disease, where in tissue, unique micro
- disease: Chromoblastomycosis (#1 cause)
- Copper penny lesions in tissue samples
- tissue: subcutaneous tissue, brain and lung tissue
- micro: 4 types of conidiation (difficult to ID)
- Fonsecaea-type = (tertiary chains of conidia, "asterisks")
- Rhinocladiella type (swollen denticles, ovoid conidia)
- Phialophora type (vase-like w/ conidiospores on top)
- Cladosporium type (large primary shield w/ short branching chains of oval conidia)
- ****USE MALDI OR PCR!!!!
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Alternaria - disease, unique colony, unique micro
- disease: Phaeohyphomycosis
- saprophytic contaminant
- colony: fast grower, grayish white/whooley -> brown w/ light border
- micro: "alternating conidia" "drumsticks" "pinecones"
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Bipolaris - disease, unique micro
- disease: Phaeohyphomycosis
- micro: conidiophers bent where conidia are attached "zig zag"
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Pneumocystic jiroveci - disease, stages, differs from other fungi, transmission, common hosts, spp, specimen, morphology
- disease: Pnemocystis pneumonia (PCP)
- affects immunocomp
- inhaled cyst replicates extracellularly -> inflammatory response
- stages: cyst (diagnostic), precyst (sporozoite), trophozoite
- differs: cell membrane contains cholesterol
- trophozoite form susceptible to osmotic disturbance
- one-two copies of ribosomal subunit gene
- transmission: unknown
- hosts: most common opp infection in HIV/AIDS
- spp: P. jiroveci = humans, P. carinii = rodents
- specimen: brochoalveloar lavage fluid, induced sputum, lung biopsy
- trophozoite: predominant form, difficult to visualize *red
- Cysts: spherical, do not bud, intracystic bodies *green
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Information about yeasts (structure, repr, morph, imp. spp)
- Eukaryotic
- unicellular
- Asexual repr: via budding
- sexual repr: via ascospores/basidiospores
- Germ tube: tubular outpouch of cell wall
- Pseudohyphae: elongated buds that form more buds
- *full cleavage, plus 'pinched' appearance
- spp: Candida (most common opportunistic fungal infection)
- Cryptococcus (very common AIDS/HIV)
- Trichosporon
- Malassezia
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What are the non-albicans candida infections?
- albicans is the vast majority (thrush, vulvovaginitis, onychomycosis, paronychomycosis, systemic infections, UTIs, heart and lung infection)
- C. glabrata, krusei, and tropicalis in certain populations (older adults, oncology pts, neonatal ICU pts)
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Candida - stains, unique colony, biochem ID, CHROMagar, C. albicans unique
- stains: strongly gram+
- colony: smooth, waxy, creamy colonies (not a mold)
- biochem: fermentation of carbohydrates
- PNA-FISH
- beta-galactose-aminidase and 1-proline aminopeptidase
- CHROM: C. albicans - green, round
- C. glabrata - light/dark mauve
- C. tropicalis - smooth, blue colonies w/ dk brown agar halo
- C. krusei - pink, rough, crenated colonies w/ pale edges
- unique: Positive germ tube, Green on CAC, cornmeal agar growth
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Cryptococcus neoformans - disease, virulence factor, stains, cultivation, unique colony, unique ID
- disease: pulmonary infection -> CNS (esp in immunocomp) -> papular skin lesions, endocarditis, hepatitis, renal infection
- vir: polysaccharide capsule protects from environment and phago
- stains: India ink defines the capsule (appears as thick-walled yeats)
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- colony: mucoid (from capsule)
- ID: rapid urease positive
- pigment on niger seed agar
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Trichosporon - disease, unique micro, unique ID
- disease: trichosporonisis, skin lesions, brain abscess, resp infections
- white piedra in immunocomp
- micro: numerous arthroconidia, few blastoconidia
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- urease positive
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Malassezia - diseases, unique micro, cultivation
- M. furfur: Tinea versicolor (brownish scaly lesions on whitey, light lesions on darky)
- *disseminated infection in children
- M. pachydermatis: fungemia in immunocomp
- *recovered from skin lesions
- micro: spaghetti and meatballs hyphae
- "bowling pin" yeast morphology
- cult: requires olive oil overlay
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Who develops antifungal stds? What are the 3 guideline documents?
- CLSI
- M27-AS: broth dilution of yeasts
- M38-A: broth dilution of mold
- M44-A: disk diffusion of yeasts
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Polyene Macrolide Antifungal Agents - structure, examples
- contain multiple conjugated double bonds and one to three ring structures
- amphotericin B
- Nystatin
- Griseofulvin
- 5-Fluorocytosine (synergistic w/ amphotericin B)
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Amphotericin B agents - function, resistant fungi
- bind to ergosterol in cell membrane
- IV or topical
- Aspergillus are resistant
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Azole antifungal agents - function, common agents
- disrupt integrity of cell membrane, inhibit ergosterol synthesis
- clotrimazole and miconazole
- fluconazole
- ketoconazole
- itraconazole
- voriconazole
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Echinocandin agents - function, types, resistant
- inhibit glucan synthesis
- Caspofungin (C. neoformans is resistant)
- Micafungin
- Anidulafungin
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