Mycology Exam 1 Flashcards
Long strands of tubelike structures. Made of chitin.
Hyphae
mat or growth of many hyphae
Mycelia
Mycelia growing above the agar
Aerial
Mycelia growing down into agar to obtain nutrients
Vegitative
Transverse subdivision of cells in hyphae
Septation
Lack of subdivision of cells in hyphae
Aseptate or “Sparsely Septate”
Dimorphic
a fungus that lives as a mold in the environment but as a yeast at body temp
Swollen structure at the end of conidiophore
Vesicle
flask-shaped segments which produce conidia
Phialides
Small, unicellular, round; borne on side of hyphal strand
Microconidia
Large, multiseptate, club of spindle-shaped; borne on conidiophore
Macroconidia
Budding forms produced by yeast
blastospores/blastoconidia
elongated blastoconidia that remain attached
Pseudohyphae
round, thick-walled resistant spores observed at the hyphal tip, on sides of hyphae, or within hyphal strand
Chlamydospores/chlamydoconidia. Associated with Candida albicans
Spores formed directly from hyphae by fragmentation of the points of septation
Arthrospores/arthroconidia
Formed by sexual reproduction by the fusion of 2 nuclei into a zygote
Ascospore
Hyphae and conidia appear clear or colorless
Hyaline
Hyphae and conidia appear dark brown due to melanin production
Dematiaceous
Asexual form of a fungus
Anamorph
Sexual form of a fungus with structures like ascospores or cleistothecia
Teleomorph
Primary routine media for fungi
Sabouraud Dextrose Agar (SAB)
Primary media for isolating Histoplasma and Blastomyces
Brain Heart Infusion Agar (BHI)
Primary media for recovering dermatophytes
Mycosel agar
What major difference is there between fungal and bacterial culture media?
Fungi use screw-cap tubes instead of plates to limit spore disseminations. Cap is kept semi-loose to allow them some O2.
Soap-like substance in media to differentiate yeast
Cornmeal Agar with Tween 80
Used to identify Cryptococcus neoformans. Turns deep brown to maroon if positive.
Niger Seed Agar (Birdseed Agar)
Used to stimulate sporulation of dermatophytes and pigment production
Potato Dextrose Agar
Media turns red if dermatophyte, can differentiate fungal infection from eczema
Dermatophyte Test Medium (i.e. Acuderm)
Urea Agar
helps differentiate several yeast and mold species
Fungal Culture growth conditions
30C for four weeks
Lactophenol cotton blue
Phenol kills fungi, cotton blue stains fruiting bodies and hyphae. Used for wet mount.
Modified Acid-Fast Stain
Used to ID Actinomycetes. Nocardia is positive. Uses a milder decolorizer than Acid Fast
10% KOH prep
Dissolves hair, nails, and skin, makes fungi more visible. Results are “yeast”, “mycelium”, or “none”.
India Ink Prep
Used to detect capsule of Cryptococcus neoformans, usually in CSF
Calcofluor white
Fluorescent stain that is taken up by chitin, requires fluorescent microscope
Macro: Rapid grower, bluish-green with white apron. Colorless reverse.
Micro: chains of spherical conidia on brush-like phialides
Penicillium
Macro: Rapid grower. Olive to pink or white. Off-white reverse.
Micro: Hyaline, septate, branched (spread out) conidiophores, chains of oval conidia
Paecilomyces
Macro: Rapid grower. Light brown and powdery (like cinnamon) with tan periphery. Tan reverse.
Micro: Large, thick-walled, round, spiny (echinulate)
Scopulariopsis
Macro: Rapid grower. White, yellow, rose, or gray. Yellow or pinkish reverse.
Micro: Think, delicate hyphae. Conidia in 1-2 cell clusters like sticky rice.
Acremonium
Macro: Rapid grower. Wooly, white to pink purple or brown. Light reverse.
Micro: Large canoe-shaped macroconidia AND small 1-2 cell clusters resembling sticky rice.
Fusarium
Macro: Rapid grower. Wooly, white to pink or green. White reverse.
Micro: spherical conidia in clusters at the phialide tips
Gliocladium
Macro: Rapid grower. White with concentric green rings.
Micro: Flask-shaped phialides with round, single celled and clustered conidia
Trichoderma
Macro: Yellow or white
Micro: Large round, knobby conidia (look like viruses)
Sepedonium
Macro: White to pale pinkish. White reverse.
Micro: Small, thin, and delicate single-celled conidia on flask-shaped conidiophores
Beauveria
Macro: White, yellow, or pink.
Micro: Septate and hyaline hyphae. Single-celled conidia directly on hyphae.
Chrysosporium
Macro: white yellow, beige, orange, or brownish. Granular to cottony.
Micro: Septate and hyaline hyphae. No conidiophores, arthroconidia alternating with empty cells.
Malbranchea
Macro: Wooly, dark gray green like a sweater. Black reverse.
Micro: Dark hyphae are septate, large club-shaped conidia like chicken legs
Alternaria
Macro: Grey-green, dark brown. Black reverse.
Micro: Thick walled conidia have 3-5 chambers with transverse septations
Bipolaris
Macro: Dark gray to black and cottony. Black reverse.
Micro: Large, dark club-shaped conidia with transverse septations
Helminthosporium
Macro: Rapid grower. Green-brown and suede-like. Black reverse.
Micro: Chains of oval conidia in brush-like clusters. Free conidia have dark attachment scars.
Cladosporium
Macro: Dark olive green to brown or black. Black reverse.
Micro: Swelling of central cell in 4-cell conidia cause “boomerang” appearance
Curvularia
Macro: Dark brown to black, cottony. Black reverse.
Micro: Septations within circular conidia are transverse and longitudinal
Ulocladium
Macro: Cottony white to tan. Orange-tan to brown or black reverse.
Micro: Septate with large, round perithecia. Tentacle-like filaments rupture to release ascospores
Chaetomium
Macro: Powdery grayish-brown or greenish. Brown to black reverse. Can diffuse red-brown pigment.
Micro: Large fruiting bodies called pycnidia. Openings through which conidia are released.
Phoma
Macro: Black, sludgy with gray fringe. Black reverse.
Micro: Young colonies produce yeast-like cells.
Aureobasidium pullulans
Macro: White, cottony, turns black with age.
Micro: Dark, oval, single celled conidia in clusters
Produces mycotoxins, “sick building syndrome”
Stachybotrys
What is the difference between sporangia and conidia?
Conidia are “naked” spores, sporangia is a sac-like structure and spores burst out
Root-like mycelium structures
Rhizoids
Macro: Lid lifter. Wooly, grayish
Micro: Hyaline, wide, aseptate. Rare rhizoids appear internodally between sporangiophores
Lichtheimia complex (Absidia)
Macro: Lid lifter. Wooly, gray to brown
Micro: Hyaline, aseptate. Large, round, branched sporangia. No rhizoids form.
Mucor
Macro: Lid lifter. Wooly, white to gray or brown
Micro: Hyaline, aseptate, unbranched sporangia with “collapsed umbrella” appearance. Nodal rhizoids.
Rhizopus
Macro: Lid lifter. White, fluffy that turns gray to black.
Micro: Broad, hyaline, aseptate. “Daisy-head” appearance with cylindrical mesosporangia
Syncephalastrum
Macro: Lid lifter.
Micro: Long branched sporangiophore ending with swollen vesicle. Spine-like denticIes with round sporangioles
Cunninghamella
Macro: Lid lifter.
Micro: Inward-curving sporangiophores encrusted with calcium oxalate
Circinella
Aspergillus - Common Characteristics
- Rapid grower
- Hyaline
- Produce Foot Cell
Macro: Grey-green with white apron. Pretty.
Micro: club-shaped vesicle, uniseriate phialides over upper 2/3 bearing long chains of conidia
Aspergillus fumigatus
Macro: Powdery, coarse, black, granular
Micro: Jet black conidia
Aspergillus niger
Macro: Yellow-green or yellow brown
Micro: Conidia cover entire surface of vesicle like a dandelion gone to seed
Aspergillus flavus
Macro: Rapid grower with cinnamon brown surface
Micro: small dome shaped vesicle, biseriate covering upper portion of vesicle
Aspergillus terreus
Macro: Rapid grower, green or tan colonies. Possible red exudate.
Micro: Reduced conidial heads resemble Penicillium
Aspergillus versicolor
Macro: green with white apron
Micro: Q-tip appearance of vesicles
Aspergillus clavatus
Macro: Thermally dimorphic fungi
Micro: Yeast phase forms sausage-shaped cells. Red diffusible pigment.
Penicillium marneffei
Tinea pedis
athlete’s foot
Tinea unguium
infection of the nails
Tinea corporis
ringworm
Tinea barbae
Barber’s itch, infection of the bearded areas of face and neck
Tinea capitis
ringworm of the scalp
Tinea favosa (favus)
chronic ringworm of the scalp causing scarring and baldness. Growth of cup-shaped crusts called scutula
Tinea cruris
jock itch
Tinea versicolor
Brownish skin discoloration of the chest and back that fluoresces under the Wood’s lamp
Common causative organism of Tinea versicolor, “spaghetti and meatballs” on 10% KOH stain
Malassezia furfur
Tinea nigra
Darkening of the palms of hands and feet
Common cause of Tinea nigra, dematiaceous branched hyphae on 10% KOH stain
Exophiala werneckii
Black piedra
stony, hard nodules along hair shaft (often scalp)
White piedra
Soft, light nodules along hair shaft (often beard and mustache)
Common cause of black piedra. Slow growing black to greenish-black colonies.
Piedraia hortae
Common cause of white piedra. Hyaline, septate hyphae with arthrospores. Yeast-like wrinkled, rubbery looking colony with true and pseudohyphae.
Trichosporon beigelii
Microsporum can infect
skin and hair
Trichophyton can infect
skin, hair, and nails
Epidermophyton can infect
skin and nails
Macro: khaki, membranous colonies.
Micro: Thin, septate, hyaline hyphae. Large, thick-walled macroconidia with 2-6 cells in “beaver tail” cluster. No microconidia.
Epidermophyton floccosum
Macro: Slow growing, white, fluffy, featureless
Micro: No micro or macroconidia. Favic chandeliers present
Microsporum audouinii
Macro: Rapid growing, wooly, white to yellow, yellow reverse.
Micro: Spindle-shaped echinulate macroconidia with >6 compartments. Can have beak-like end. Some small club-shaped microconidia.
Microsporum canis
Macro: Rapid growing, beige, granular with irregular border. Cinnamon brown reverse.
Micro: Ellipsoidal, thin-walled macroconidia with 6-9 cells. Club-shaped microconidia.
Microsporum gypseum
Common characteristics of Microsporum species
- Thick-walled macroconidia with spiny surfaces
- Few microconidia
- Ectothrix infections
- Fluoresces under Wood’s lamp
Common characteristics of Trichophyton species
- Many microconidia
- Pencil-shaped macroconidia
- Endothrix and ectothrix infections
Macro: Slow growing, white, cottony to grainy
Micro: Clusters of round microconidia, cigar-shaped macroconidia with <6 cells, possible spiral hyphae.
Special tests: Positive for hair penetration and urease
Trichophyton mentagrophytes
Macro: Slow growing, white sometimes with red pigment. Wine-red reverse.
Micro: Oval microconidia directly on hyphae like “birds on a wire”. Possible spiral hyphae.
Special tests: Negative for hair penetration and urease.
Trichophyton rubrum
Macro: Slow growing
MIcro: Club-shaped microconidia directly on hyphae. Intercalary and terminal chlamydospores.
Trichophyton tonsurans
Drug classes used to treat fungi
- Polyenes
- Azoles (usually best)
- Candins