Microbiology 2: Mycology, Mold and Yeasts

What does the growth on an overlaid agar look like for Malassezia furfur?

"Bowling pin" or "Pop bottle"

What are the characteristics of fungi?

- Eukaryotes; have nuclei - aerobes and live on dead, organic matter - Chitin in cell walls - Neutral pH - Examples are yeasts, molds, mushrooms

What are clinical specimens for fungal cultures?

- respiratory secretions - cerebrospinal fluid (CSF) - blood - eye (corneal scrapings) - hair, skin, and nail scrapings - vaginal - urine - tissue, bone marrow, and sterile body fluids

Explain the incubation requirements for fungal media:

- room temperature (30 C) - minimum of 21-30 days - humidity: 40%-50% - examined at least three times a week

What are common virulence factors of fungal infections?

- size of the organism - ability to grow at 37 degrees C at a neutral pH - conversion of mycelial form to yeast or spherule form - toxin production

Sparsely septate hyphae

AKA aseptate hyphae. Contain few separations

How should colony morphology be noted for fungal cultures?

Color and growth should be noted for front and reverse surfaces of the agar

Differentiate Endothrix and Ectothrix

Endothrix: hair shaft is filled with arthroconidia Ectothrix: spores are found around the hair shaft

Mycology is the study of:

Fungi

What is the most important any easiest test to perform for yeast?

Germ tube

What is Trichosporon spp. stained for?

Hyaline hyphae Numerous arthroconidia Few blastoconidia

Which Trichophyton does not invade the hair shaft and which one does? Trichophyton rubrum/ Trichophyton mentagrophytes

Invades hair shaft: Trichophyton mentagrophytes Does not invade hair shaft: Trichophyton rubrum

What does "lid lifter" associate with?

Mucorales

For Trichophytons, do infected hairs fluoresce under Wood's lamp (UV light)?

No, infected hairs do not fluoresce under Wood's lamp

What is the identification for Trichosporon spp.?

Urease positive and substrate utilization profile

Where are Mucorales distributed?

Worldwide

At what temperature is the mold phase of a dimorphism organism? a. 22-25 degrees C b. 4-10 degrees C c. 37 degrees C with increased CO2

a. 22-25 degrees C

Which of the following is associated with skin and nails? a. Epidermophyton b. Microsporum c. Trichophyton

a. Epidermophyton

What do you examine the skin scrapings with for Malassezia furfur? a. KOH b. India ink c. florescent light

a. KOH

Which of the following is associated with Ringworm of the Beard? a. Tinea barbae b. Tinea pedis c. Tinea capitis d. Tinea unguium

a. Tinea barbae

Which of the following is associated with Ringworm of the Scalp? a. Tinea capitis b. Tinea corporis c. Tinea cruris d. Tinea unguium

a. Tinea capitis

Which of the following occasionally reproduced asexually? a. anamorph b. teleomorph c. synanomorph

a. anamorph

What does verrucous mean? a. furrowed or convoluted b. slightly raised in the center c. furrows radiate out from the center (wrinkle)

a. furrowed or convoluted

How is velvety texture explained? (fungal) a. low aerial mycelium b. dense and powdery c. loose, high aerial mycelium d. high aerial mycelium that is slightly matted down

a. low aerial mycelium

Which of the following describes Zygospores? a. sexual phase of zygomycetes b. saclike structure containing sporagiospores only in zygomycetes c. formed directly from hyphae but are round d. structure that contains the conidia

a. sexual phase of zygomycetes

What specimen is used for Malassezia furfur? a. skin scrapings b. vaginal swab c. feces d. blood

a. skin scrapings

Which describes Ascospores? a. spores contained in the asci or sexual spores b. fragments of hyphae that form spores c. saclike structure containing sporagiospores only in zygomycetes d. large structure containing sexual spores

a. spores contained in the asci or sexual spores

Infections often involve the lungs but can disseminate to any organ: a. systemic mycoses b. oportunistic mycoses c. subcutaneous mycoses d. superficial cutaneous mycoses

a. systemic mycoses

Asexual reproduction: how are phialides described? a. vase-like structures b. ringed structures c. fruiting structures

a. vase-like structures

Which molds grow in agar? a. vegetative mycelium b. aerial mycelium c. Zygomycota d. Ascomycota

a. vegatative mycelium

What is the color of the reverse side of Trichophyton rubrum? a. wine-red b. blue-green c. rose-brown d. creamy white

a. wine-red

What is dimorphism?

ability to exist in two forms based on growth conditions

What media is preferred over screw-capped agar for fungal cultures?

agar plants

How do Dermatophytes utilize keratin?

as nitrogen source

How do ascomycota reproduce sexually?

ascospores

What Candida spp. is prevalent in patients with hematological malignancies? a. C. krusei b. C. tropicalis c. C. parasilosis

b. C. tropicalis

What is the most premier cause of yeast infections in the world? a. blastschizomyces b. Candida albicans c. Candida glabrata

b. Candida albicans

What yeast tends to be aggressive and difficult to treat with traditional anti fungal therapy? a. Candida albicans b. Candida glabrata c.Cryptococcus neoformans

b. Candida glabrata

What yeast is the India ink test used for? a. Candida albicans b. Cryptococcus neoformans c. Malassezia furfur

b. Cryptococcus neoformans

What is the most commonly used detection method for molds? a. potassium hydroxide (KOH) preparation b. Lactophenol cotton blue mounts c. India ink stain d. Calcofluor white stain

b. Lactophenol cotton blue mounts

Which of the following is associated with hair and skin? a. Epidermophyton b. Microsporum c. Trichophyton

b. Microsporum

Which of the following is associated with Ringworm of the Body? a. Tinea capitis b. Tinea corporis c. Tinea cruris d. Tinea unguium

b. Tinea corporis

Which of the following is associated with Ringworm of the Feet? a. Tinea barbae b. Tinea pedis c. Tinea capitis d. Tinea unguium

b. Tinea pedis

Which molds grow "upward and outward" on a plate? a. vegetative mycelium b. aerial mycelium c. Zygomycota d. Ascomycota

b. aerial mycelium

How is granular texture explained? (fungal) a. low aerial mycelium b. dense and powdery c. loose, high aerial mycelium d. high aerial mycelium that is slightly matted down

b. dense and powdery

Which is associated with Asocarp? a. asexual reproduction cycle b. large structure containing sexual spores c. fragments of hyphae that form spores d. formed directly from hyphae but are round

b. large structure containing sexual spores

What is overlaid on a blood culture for Malassezia furfur? a. E. coli b. olive oil c. antibiotics

b. olive oil

Infections occur in patients who are immunocompromised: a. systemic mycoses b. oportunistic mycoses c. subcutaneous mycoses d. superficial cutaneous mycoses

b. opportunistic mycoses

Asexual reproduction: how are annelides described? a. vase-like structures b. ringed structures c. fruiting structures

b. ringed structures

Which of the following describe Sporangium? a. sexual phase of zygomycetes b. saclike structure containing sporagiospores only in zygomycetes c. formed directly from hyphae but are round d. structure that contains the conidia

b. saclike structure containing sporagiospores only in zygomycetes

What does umbonate mean? a. furrowed or convoluted b. slightly raised in the center c. furrows radiate out from the center (wrinkle)

b. slightly raised in the center

Which describes conidiophores? a. spores contained in the asci or sexual spores b. Structure that contains the conidia c. fragments of hyphae that form spores d. sexual phase of zygomycetes

b. structure that contains the conidia

Which of the following has "perfect sexual reproduction"? a. anamorph b. teleomorph c. synanomorph

b. teleomorph

What is Candida albicans associated with? a. scarlet fever b. thrush c. "flu" d. diarrhea

b. thrush

Cryptococcus neoformans can be presumptively identified by what rapid test? a. citrate b. urease c. MR-VP

b. urease

What might Trichosporon spp. cause in immunocompromised patients? a. thrush b. white piedra c. leukemia

b. white piedra

How do basidiomycota reproduce sexually?

basidiospores

How would yeasts be described? biochemical or filamentous?

biochemical

How do yeasts replicate?

budding or fission

At what temperature is the yeast phase of a dimorphism organism? a. 22-25 degrees C b. 4-10 degrees C c. 37 degrees C with increased CO2

c. 37 degrees C with increased CO2

Which Candida spp is the primary cause of fungemia in the NICU? a. C. krusei b. C. tropicalis c. C. parasilosis

c. C. parasilosis

What causes brownish scaly lesions on light-skinned individuals (tinea versicolor)? a. Candida albicans b. Cryptococcus neoformans c. Malassezia furfur

c. Malassezia furfur

What has a hyphal arrangement that looks like "spaghetti and meatballs"? a. Candida albicans b. Cryptococcus neoformans c. Malassezia furfur

c. Malassezia furfur

Which of the following is associated with Ringworm of the Groin? a. Tinea capitis b. Tinea corporis c. Tinea cruris d. Tinea unguium

c. Tinea cruris

Which of the following is associated with hair, skin, and nails? a. Epidermophyton b. Microsporum c. Trichophyton

c. Trichophyton

Which mold looks like "birds on a fence"? a. Microsporum gypseum b. Epidermophyton floccosum c. Trichophyton rubrum d. Aspergillus niger

c. Trichophyton rubrum

Which of the following describes Chlamydoconidia? a. sexual phase of zygomycetes b. saclike structure containing sporagiospores only in zygomycetes c. formed directly from hyphae but are round d. structure that contains the conidia

c. formed directly from hyphae but are round

Which describes Arhroconidia? a. spores contained in the asci or sexual spores b. Structure that contains the conidia c. fragments of hyphae that form spores d. sexual phase of zygomycetes

c. fragments of hyphae that form spores

Asexual reproduction: how are conidia described? a. vase-like structures b. ringed structures c. fruiting structures

c. fruiting structures

What does rugose mean? a. furrowed or convoluted b. slightly raised in the center c. furrows radiate out from the center (wrinkle)

c. furrows radiate out from the center (wrinkle)

How is cottony texture explained? (fungal) a. low aerial mycelium b. dense and powdery c. loose, high aerial mycelium d. high aerial mycelium that is slightly matted down

c. loose, high aerial mycelium

Which of the following is NOT associated with Mucorales? a. diabetes mellitus b. prolonged drug therapy c. pernicious anemia d. dead tissue e. lung infections, GI problems f. all of the above

c. pernicious anemia

Infections confined to subcutaneous tissue without dissemination: a. systemic mycoses b. oportunistic mycoses c. subcutaneous mycoses d. superficial cutaneous mycoses

c. subcutaneous mycoses

Which of the following has different asexual forms in the same fungus? a. anamorph b. teleomorph c. synanomorph

c. synanomorph

How do Deuteromycota reproduce asexually?

conidia

How do ascomycota reproduce asexually?

conidia

What yeast produces a pigment on niger seed agar? a. a. C. krusei b. C. tropicalis c. C. parasilosis d. C. neoformans

d. Cryptococcus neoformans

Which of the following is associated with Ringworm of the Nail? a. Tinea barbae b. Tinea pedis c. Tinea capitis d. Tinea unguium

d. Tinea unguium

What media is used for fungal cultures? a. With & without cyclohexamide b. Saboraud's agar with and without antibacterial agent c. brain heart infusion (BHI) d. all of the above e. b and c only

d. all of the above

On what are Mucorales found? a. decaying vegetable matter b. bread c. in the soil d. all of the above

d. all of the above - decaying in vegetable matter - bread - in soil

How are Mucorales infections acquired? a. inhalation b. percutaneous routes c. ingestion of spores d. all of the above

d. all of the above - inhalation - percutaneous routes - ingestion of spores

How is wooly texture explained? (fungal) a. low aerial mycelium b. dense and powdery c. loose, high aerial mycelium d. high aerial mycelium that is slightly matted down

d. high aerial mycelium that is slightly matted down

Blastoshizomyces app is an emerging pathogen found in primary _______ patients? a. young b. adult c. obese d. immunocompromised

d. immunocompromised

Infections that involve the hair, skin, or nails without direct invasion of deep tissue: a. systemic mycoses b. oportunistic mycoses c. subcutaneous mycoses d. superficial cutaneous mycoses

d. superficial cutaneous mycoses

Cryptococcus neoformans can cause what? a. Meningitis b. Pneumonia c. Septicemia d. Hepatitis e. A, B, and C only f. A, B, and D only

e. a, b, and c only

Which of the following are considered vegetative mycelium? a. Arthrospores b. Chlamydospores c. Conidia d. Blastosphores e. Sproangia f. A, B, D only g. C & E only h. all of the above

f. A, B, D only

Cornmeal agar determines if the yeast produces: a. Blastoconidia b. Arthroconidia c. Pseudohyphae d. True hyphae e. Chlamydoconidia f. All of the above

f. all of the above

How would molds be described? biochemical or filamentous?

filamentous

How are arthroconidia formed?

fragmentation of fertile hyphae

Which of the following are considered Aerial mycelium? a. Arthrospores b. Chlamydospores c. Conidia d. Blastosphores e. Sproangia f. A, B, D only g. C & E only h. all of the above

g. C & E only

Blastoschizomyces spp. is isolated from patients with debilitating diseases, such as: a.Leukemia b.Renal Transplants c.Ambulatroy dialysis d.Spondyciscitis e. Osteomyelitits f. A and C only g. all the above

g. all the above

For what specimen is the Potassium hydroxide (KOH) preparation used?

hair and skin

septate hyphae:

hyphae with cross walls

What do dermatophytes require for growth?

keratin

What conidia does this explain: smooth, club-shaped and thin walled macroconidia or microconidia

macroconidia

What conidia does this explain: sperhical, pyriform, or clavate macroconidia or microconidia

microconidia

What do yeast colonies look like?

small, smooth, creamy, moist

How do zygomycota reproduce asexually?

sporangiospores

What is polymorphism?

the ability to form yeast and mold in the same culture

How do zygomycota reproduce sexually?

zygospores