Mycology Homewok Questions:
Fungal cultures should held for how many days before being discarded as negative: 3 days 7 days 14 days 30 days
30 days
Septate hyaline hyphae and a young conidiophore terminating in a swollen vesicle are distinguishing characteristics for which one of the following molds; a. Scopulariopsis b. Gliocladidum c.Acremonium d. Aspergillus e. Penicillium
Aspergillus
The genus of hyaline mold that causes the majority of human disease is: Aspergillus Penicillium Scedosporium Fusarium
Aspergillus
Which of the following is a fluorescent stain used for direct observation of yeast and fungal elements from clinical specimens? a. Lactophenol cotton blue b. Calcofluor white c. India Ink d. Wright stain
Calcofluor white
The fungal organism most commonly found in vaginal infections is: a. Cryptococcus neoformans b. Geotrichum candidum c. Candida albicans d. Coccidioides immitis e. Candida (Torulopsis) glabrata
Candida albicans
Capsule formation is a characteristic microscopic finding of: a. Penicillium b. Cryptococcus neoformans c. Scedosporium apiospermum d. Candida albicans
Cryptococcus neoformans
The observation of rapid urease activity is helpful in making a presumptive identification of: a. Candida albicans b. Cryptococcus neoformans c. Candida tropicalis d. Torulopsis glabrata
Cryptococcus neoformans
A dark brown, fluffy mold, with black reverse grew in 6 days. Multi-celled, "hand-grenade"- shaped conidia in chains were observed microscopically. This fungus is most likely a: a. Dermatophyte b. Zygomycete c. Dematiaceous mold d. Dimorphic fungus
Dematiaceous mold
A trip to which of the following regions in the United States carries with it the possible exposure to the fungal agents causing coccidioidomycosis: a. Desert southwest b. Missouri Valley c. Southeastern states d. Mississippi Valley
Desert southwest
All of the organisms listed below possess phialides except: Aspergillus fumigatus Penicillium Paecilomyces Fusarium
Fusarium
Each of the following is classified as a Dematiaceous fungus except: a. Alternaria b. Nigrospora c. Fusarium d. Cladosporium
Fusarium
Sinus drainage from an AIDS patient produced a lavender-colored colony after 4 days incubation. Microscopically, sickle-shaped macroconidia and hyaline hyphae were observed. This organism is most likely: Fusarium Paecilomyces Penicillium Aspergillus
Fusarium
Which superficial fungus has a characteristic "spaghetti & meatballs" microscopic morphology and requires a lipid overlay for growth? Exophiala werneckii Trichophyton tonsurans Malassezia furfur Microsporum gypseum
Malassezia furfur
An organism known to cause skin infections in children who have had close contact with a new puppy is (are): Trichophyton mentagrophytes Microsporum canis Microsporum gypseum All of the above
Microsporum canis
Several children in a family presented to their pediatrician with symptoms of tinea capitis. Hairs from the affected areas fluoresced green under a Wood's lamp. Cultures of these hairs produced aerial mycelia and pointed macroconidia. These isolates were most likely: Trichophyton rubrum Epidermophyton floccosum Microsporum canis Microsporum gypseum
Microsporum canis
Candida albicans is an agent of: a. "Valley fever" b. Chromomycosis c. Tinea corporis d. Oral or vaginal thrush
Oral or vaginal thrush
Mycetomas are most commonly associated with which of the following fungal agents? a. Pseudoallescheria boydia b. Fonsecaea pedrosoi c. Cladosporium d. Phialophora
Pseudoallescheria boydia
Blastoconidia that have elongated are termed: a. True hyphae b. Chlamydospores c. Conidia d. Pseudohyphae
Pseudohyphae
A fluffy white mold produced rhizoids, aseptate hyphae and sporangia microscopically. This organism most likely is: Penicillium Cunninghamella Rhizopus Mucor
Rhizopus
Select from the following the correct fungal agent/geographical association: a. Histoplasmosis - desert southwest U.S. b. Blastomycosis - Gulf Coast, U.S. c. Coccidioidomycosis - Missouri valley d. Sporotrichosis - worldwide e.Aspergillosis - Midwest
Sporotrichosis - worldwide
Two species of Trichophyton produce colonies on potato dextrose agar plates that are similar in color and appearance. In vitro hair perforation is used to differentiate which two fungi? T. mentagrophytes & T. rubrum T. tonsurans & T. schoenleinii T. tonsurans & T. mentagrophytes T. verrucosum & T. rubrum
T. mentagrophytes & T. rubrum
A culture from a patient with tinea corporis produced a red colored colony on Sabouraud's dextrose agar following 3 weeks of incubation. Microscopically, teardrop-shaped micronconidia along the sides of the hyphae were observed. The most likely identification is: Trichophyton rubrum Trichophyton tonsurans Microsporum canis Trichophyton violaceum
Trichophyton rubrum
A rapidly growing mold with broad asptate hyphae produced a gray colony resembling cotton candy that lifted the lid off the Petri dish. Microscopically, sporangiophores were seen between the rhizoids, but not opposite them. A conical apophysis was observed below the columella. What is the most likely identification? a. Absidia b. Cunninghamella c. Rhizopus d. Aspergillus
a. Absidia
The location of the rhizoids is the major clue in the differentiation of Rhizopus from: a. Absidia b. Circinella c. Cunninghamella d. Mucor e. Syncephalastrum
a. Absidia
In a germ tube preparation, a yeast isolate produced a few cells with hyphal extensions with constrictions where attached to the mother cells. Candida albicans was ruled out when confirmatory tests were performed. The most likely species of yeast is: a. Candida tropicalis b. Cryptococcus neoformans c. Candida glabrata d. Rhodotorula rubra
a. Candida tropicalis
Thick-walled, rectangular, or barrel-shaped alternate arthroconidia are characteristic of which of the following dimorphic molds? a. Coccidioides immitis b. Sporothrix schenckii c. Histoplaasma capsulatum d. Blastomyces dermatitidis
a. Coccidioides immitis
What fungus produces characteristic dark, round conidia with horizontal and vertical septa, supported on short conidiophores? a. Epicoccum b. Curvularia c. Gliocladium d. Alternaria e. Nigrospora
a. Epicoccum
What is the characteristic microscopic morphology of Penicillium species? a. Flask-shaped phialides with chains of round phialoconidia - "brush-like" appearance b. Lemon-shaped annelloconidia in chains c. Thick-walled, smooth- or rough-walled macroconidia d. Curved poroconidia with an enlarged central cell
a. Flask-shaped phialides with chains of round phialoconidia - "brush-like" appearance
Which of the following structures is not invaded by the genus Epidermophyton? a. Hair b. Nails c. Skin d. None of the above
a. Hair
The hyaline mold Fusarium species has been implicated in corneal ulcers and mycetomas. The colony morphology & microscopic characteristics most closely resemble which of the following: a. Rapid grower that usually produce a lavender pigment and crescent-shaped, septate macroconidia b. Rapid grower "lid lifer" that produces aseptate hyphae with nodal rhizoids c. Slow grower that is granular & light tan with orange-colored reverse and abundant macroconidia d. Slow grower that is gray-brown and produces macroconidia in chains
a. Rapid grower that usually produce a lavender pigment and crescent-shaped, septate macroconidia
The potassium hydroxide direct mount technique is most commonly used to examine which of the following specimens: a. Skin b. CSF c. Subcutaneous aspirate d. Bone marrow
a. Skin
What aseptate fungus produces branched sporangiophores that terminate in vesicles that are surrounded by cylindrical merosporangia filled with round sporangiospores? The microscopic morphology of the fungus resembles that of Aspergillus species. a. Syncephalastrum b. Mucor c. Rhizopus d. Saksenaea e. Cunninghamella
a. Syncephalastrum
Which of the following temperatures should fungal cultures be incubated: a. 2-4oC b. 30oC c. 37oC d. 56oC
b. 30oC
The India ink stain is used to presumptively identify which organism? a. Aspergillus niger in blood b. Cryptococcus neoformans in CSF c. Histoplasma capsulatum in CSF d. Candida albicans in blood or body fluids
b. Cryptococcus neoformans in CSF
What dematiaceous fungus is characterized by a microscopic morphology demonstrating 1o, 2o, and 3o blastoconidia in loosely organized conidial heads? a. Exophiala jeanselmei b. Fonsecaea pedrosoi c. Wangiella dermatitidis d. Cladosporium trichoides
b. Fonsecaea pedrosoi
A rapidly growing fungal colony on Sabouraud's dextrose agar appeared as a green colony. The microscopic examination revealed swollen-tipped conidiophores with phialides and conidia in chains. The most likely identification of this isolate is: a. Aspergillus b. Gliocladium c. Fusarium d. Penicillium
b. Gliocladium
A rapidly growing hyaline mold began as a white colony, but became dark green with hyphae, flask-shaped phialides with balls of conidia at the tips of the phialides were seen. What is the most likely identification? a. Penicillium b. Gliocladium c. Paecilomyces d. Aspergillus fumigatus
b. Gliocladium
What fungus produces chains of lemon-shaped annelloconidia that become echinulate with age? a. Scedosporium b. Scopulariopsis c. Fusarium d. Paecilomyces e. Acremonium
b. Scopulariopsis
This dimorphic fungus appears as oval or elongated cigar shapes, some with multiple buds in its yeast form: a. Coccidioides immitis b. Sporothrix schenckii c. Histoplasma capsulatum d. Blastomyces dermatitidis
b. Sporothrix schenckii
A KOH prep of skin scrapings reveals numerous hyphae and large, spherical blastospores resembling "spaghetii and meatballs". This patient probably has: a. Tinea corporis b. Tinea versicolor c. Tinea capitis d. Tinea unquium
b. Tinea versicolor
What fungus demonstrates endothrix hair invasion and causes black dot tinea capitis, epidemic in black school-age children? a. Microsporum audouinii b. Trichophyton tonsurans c. Trichophyton schoenleinii d. Trichophyton violaceum e. Epidermophyton floccosum
b. Trichophyton tonsurans
The genus Candida reproduces by: a. arthrospores b. blastoconidia c. ascospores d. sporangiospores
b. blastoconidia
The diagnostic forms of Nigrospora species typically produce conidia which appear as: A. single cells in chains B. multi-celled macroconidia with transverse septa C. multi-celled macroconidia with transverse and longitudinal septa D. black, single spherical conidia supported by a short urn-shaped conidiophore
black, single spherical conidia supported by a short urn-shaped conidiophore
A yeast isolate may be considered to be normal flora when recovered from each of the following clinical specimens except: sputum stool blood vaginal secretion
blood
Allergic pulmonary disease is most commonly due to which of the following? a. A. niger b. A. terreus c. A. fumigatus d. A. clavatus
c. A. fumigatus
What type of asexual conidia may be terminal, sessile (on sides), or within the hyphal strand (intercalary) and are formed during unpleasant environmental conditions? a. Macroconidia b. Blastoconidia c. Chlamydoconidia d. Annelloconidia
c. Chlamydoconidia
To avoid laboratory-associated infections, extreme caution should be exercised when examining or subculturing which of the following arthrospore-producing fungi: a. Geotrichum candidum b. Trichosporon capsulatum c. Coccidioides immitis d. Nocardia asteroides
c. Coccidioides immitis
A sputum yeast isolate had the following characteristics: absence of pseudohyphae on cornmeal agar preparations, nitrates not assimilated, and urease produced at 37o C. The most likely identification is: a. Saccharomyces cerevisiae b. Geotrichum candidum c. Cryptococcus neoformans d. Candida albicans
c. Cryptococcus neoformans
Which phylum is known as the "Fungi Imperfecti" because the fungi in this phylum have no known sexual stage? a. Ascomycota b. Basidiomycota c. Deuteromycota d. Zygomycota
c. Deuteromycota
Smooth-walled, club-shaped macroconidia were observed from a microscopic mount of a fungus cultured from a patient with athlete's foot. The macroconidia were arranged singly or in clusters of two to three from the tips of short conidiophores. The colonies did not produce microconidia. What is the most likely identification? a. Trichophyton b. Alternaria c. Epidermophyton d. Microsporum
c. Epidermophyton
The stain that is used most commonly to stain fungal elements is: a. Gram stain b. India Ink c. Lactophenol-cotton blue d. Methylene Blue
c. Lactophenol-cotton blue
A sample of hair taken from a six year old child with an apparent ringworm infection fluoresces bright yellow-green under a Wood's lamp. This organism most likely belongs to what genus? a. Trichosporon b. Epidermophyton c. Microsporum d. Trichophyton
c. Microsporum
Sporangia are distinguishing characteristics for which one of the following organisms: a. Aspergillus b. Penicillium c. Mucor d. Scopulariopsis
c. Mucor
Which fungus is the causative agent of favus, a severe form of tinea capitis? a. Microsporum audouinii b. Epidermophyton floccosum c. Trichophyton schoenleinii d. Trichophyton violaceum
c. Trichophyton schoenleinii
Which Aspergillus species has characteristic rough or spiny conidiophores and its phialides cover the entire vesicle? a. A. fumigatus b. A. terreus c. A. clavatus d. A. flavus e. A. niger
d. A. flavus
Trichophyton is known to invade which of the following: a. Skin b. Nails c. Hair d. All of the above
d. All of the above
Recovered from a case of mycetoma was a dark fungus, microscopically presenting with "curved" macroconidia with an enlarged central cell. This organism is most likely: a. Alternaria b. Aspergillus niger c. Cladosporium d. Curvularia
d. Curvularia
The observation of tuberculate macroaleureospores with hair-like projections (echinulate) is characteristic and diagnostic for: a. Coccidioides immitis b. Blastomyces dermatitidis c. Paracoccidioides brasiliensis d. Histoplasma capsulatum e. Geotrichum candidum
d. Histoplasma capsulatum
All of the following opportunistic fungi are hyaline except ____________________. a. Penicillium b. Acremonium c. Gliocladium d. Nigrospora e. Scopulariopsis
d. Nigrospora
Which of the following accurately describes the microscopic morphology of the aseptate Saksenaea species? a. Unbranched sporangiophores opposite rhizoids support round sporangia filled with sporangiospores b. Branched sporangiophores terminate in vesicles on which one-celled, round sporangiola form at the tips of swollen denticles c. Branching sporangiophores between rhizoids support pear-shaped sporangia filled with sporangiospores d. Rhizoids are opposite flask-shaped sporangia that are filled with elongated sporangiospores
d. Rhizoids are opposite flask-shaped sporangia that are filled with elongated sporangiospores
The urease test is used to differentiate which two species of Trichophyton: a. T. tonsurans and T. mentagrophytes b. T. tonsurans and T. schoenleinii c. T. tonsurans and T. violaceum d. T. mentagarophytes and T. rubrum
d. T. mentagarophytes and T. rubrum
If the culturing of a fungal specimen is delayed, the specimen should never be: a. held at room temperature b. refrigerated c. incubated at 35oC d. frozen
d. frozen
A fungus usually classified as a nonpathogen, but capable of causing disease in an immunologically compromised patient is known as: a. saprobic b. hyaline c. aseptate d. opportunistic
d. opportunistic
What dematiaceous fungus produces cylindrical, 4-5 celled poroconidia with truncate hila that are usually in clusters along a bent-knee conidiophores? a. Alternaria b. Cladosporium c. Fusarium d. Exserohilum e. Bipolaris
e. Bipolaris
All of the following produce micrconidia except: a. Microsporum canis b. Trichophyton violaceum c. Microsporum gypseum d. Trichophyton rubrum e. Epidermophyton floccosum
e. Epidermophyton floccosum
A lactophenol cotton blue mount reveals slender tapering conidophores bearing small pear shaped conidia in "rosette"-like clusters. The most likely presumptive identification is: a. Blastomyces dermatitidis b. Coccidioides immitis c. Histoplasma capsulatum d. Paracoccidioides brasiliensis e. Sporothrix schenckii
e. Sporothrix schenckii
