Fungi/Mycology Flashcards
Characteristics of Fungi
Eukaryotes
Heterotrophs
Ergosterol in cell membrane instead of cholesterol
Cell wall of chitin, mannans and glucans
yeast or mold
Yeast
Unicellular
reproduce by budding
colonies are pasty and smooth
Molds
composed of hyphae which together form mycelium
colonies are cottony, fuzzy or woolly
Types of Fungi
septate hyphae or aseptate hyphae
Thermal Dimorphicism
some fungis grow as yeast or mold depending on the temperature.
Mold- 25C
Yeast- 37C (body temp)
Pseudohyphae
chains of elongated yeast, devoid of septa, constrictions between the cells
Polymorphic/pleomorphic
candida albicans is an example bc of its ability to grow as yeast, hyphae or pseudohyphae
Sexual Reproduction of fungi
meiosis
Asexual Reproduction of fungi
mitosis- formation of spores that germinate to give rise to a new organism
Conidia
asexual spore not enclosed in sacs
blastoconidia/blastospore
budding daughter cells produce by yeasts
arthrospores/arthroconidia
formed by fragmentation from preexisting cells in the hyphae
sporangiospores
enclosed in sacs called sporangia
Lab tests to ID fungi
morphology
isolation/culture
immunoassay/AG detection
PCR, SDA, Woods Lamp, KOH
Superficial Mycoses
Pitryiasis versicolor or tinea versicolor
skin or hair, nondestructive
Pitryiasis versicolor or tinea versicolor
Malassezia spp
lipophilic yeasts that are normal skin biota
Disease occurs when yeasts converts to hyphal form and there is excessive proliferation.
More common in tropics
more common in younger indv, using oils/lotions, sweaty, corticosteroid use
Lab Dx: skin scraping, KOH, microscope observation, culture
SPAGHETTI and MEATBALL appearance, blastoconidia
hypo/hyperpigmentation
Cutaneous mycosis
infections of keratinized layer of skin, hair, nails
Dermatophytosis, tinea, ringworm
molds: tricophyton, microsporum, epidermophyton
antropophilic
zoophilic
geophilic
spore germination
lab dx: collect specimen, treat with KOH, culture
Microsporum
Mostly Macroconidia
Tricophyton
Many microconidia, macro usually absent or cigar shaped
Epidermophyton
NO microconidia. Thin walled MACROCONIDIA, produced in clusters coming straight form the hyphae
Clinical Presentations of Tinea
Tinea capitis, corporis, mannum, pedis, endothrix/ectothrix, barbae, cruris, facie, unguium
hyperpigmentation
Subcutaneous Mycoses
infections of the deeper layers of the skin, muscle, fascia, or cornea
immune response produces varying levels of tissue destruction
sporothrix schenckii
Sporothrix schenckii
Sporotrichosis: dimorphic, yeast is round, oval, cigar shaped. Asteroid bodies. Mold is septate hyphae with small oval conidia in a daisy pattern
rose gardeners disease; subcutaneous nodules or ulcerative lesions in a linear pattern. Rarely pulmonary or disseminated distribution in bones, joints, lungs, CNS
soil/vegetable matter (hay or rose thorns)
garden workers, ag workers
Sporothrix brasiliensis is zoonotic
Fungal keratits
infection of cornea caused by molds in warm/humid areas
Candida, Aspergillus, Fusarium
Risks: Trauma, immunosuppression, wearing contacts/overnight
Lab Dx: corneal scrapings, KOH/calcofluor white, microscope, PCR, culture
Fusarium (solani)
Canoe shaped macroconidia
cylindrical microconidia
Opportunistic Mycoses
Candidiasis
murcomycosis
apergillosis
cryptococcosis
pnuemocystis pneumonia
IC, metabolic conditions, implanted catheters, altered microbiomes
