Mycology Final

Aspergillus spp.

A bone marrow transplant patient develops an abrupt fever with respiratory distress. Despite treatment with antifungal medications, the patient dies on the fifth day. The following organism was isolated from both sputum and blood cultures. Identify the organism seen in the image below. Histoplasma capsulatum Aspergillus spp. Mucor spp. Rhizopus spp.

Trichophyton 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 microconidia along the sides of the hyphae were observed. The most likely identification is: Microsporum canis Trichophyton violaceum Trichophyton rubrum Trichophyton tonsurans

Rhizopus

A fluffy white mold produced rhizoids, aseptate hyphae and sporangia microscopically. This organism most likely is: Mucor Rhizopus Cunninghamella Circinella

opportunistic

A fungus usually classified as a nonpathogen, but capable of causing disease in an immunologically compromised patient is known as: hyaline opportunistic aseptate saprobic

Yeast

A patient sputum contains dimorphic fungi. If the sputum was put on a slide what structure would you expect to see? Cocci Hypae Yeast Rods

Fusarium spp

A patient who wears long-term contact lenses comes to her physician after noting a small spot on her cornea. Collection of the lesion for culture produced a fast-growing mold with a slight pink color on the surface. Microscopic review showed the following organism. This organism is most likely Fusarium spp. Geotrichum spp. Mucor spp. Mircosporum spp.

Trichophyton mentagrophytes.

A patient with thickened and discolored nails was diagnosed with onychomycosis. A scraping of the nail was sent for culture. Microscopic analysis of the mold colony growth revealed the following morphology. The most likely identity of this organism is Microsporum canis. Microsporum gypseum Epidermophyton spp. Trichophyton mentagrophytes.

a

A presumptive diagnosis of tinea capitis from Microsporum canis can be confirmed by: a. direct examination of infected hair for fluorescence under a Wood's lamp b.production of abundant microaleuriospores on Sabouraud's dextrose agar c.orange-colored reverse of colony d.positive urea test

Absidia

A rapidly growing gray-white mold with aseptate hyphae and internodal derivation of rhizoids might be identified as: Mucor Circinella Absidia Rhizopus

Absidia spp.

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 not opposite them. A conical apophysis was observed below the columella. What is the most likely identification? Penicillium spp. Aspergillus spp. Absidia spp. Rhizopus spp.

Microsporum

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? Microsporum Trichosporon Epidermophyton Trichophyton

Aspergillus flavus

A sputum specimen from a cancer patient with pneumonia produced a rapidly growing fluffy yellow-white colony. A scotch tape preparation from the colony revealed conidia that grew in short chains from the entire surface of the vesicle. This organism is probably: Aspergillus fumigatus Aspergillus flavus Penicillium Aspergillus niger

Microsporum canis.

A young boy develops itchy, dry scaly lesions on his leg with a raised, red, outer edge. A culture of the lesion reveals the following organism in a lactophenol cotton blue stain. This organism is most likely Epidermophyton spp. Microsporum canis. Acremonium Trichophyton spp.

Fusarium spp

All of the organisms listed below possess phialides except: Penicillium spp Fusarium spp Aspergillus fumigatus Paecilomyces spp

A. fumigatus

Allergic pulmonary disease is most commonly due to which of the following? A. terreus A. niger A. fumigatus All choices are correct

M. canis

An organism known to cause skin infections in children who have had close contact with a new puppy is (are): M. gypseum all of the choices T. mentagrophytes M. canis

septate hyphae

Aspergillus fumigatus: sporulation on full vesicle aseptate hyphae septate hyphae phialides absent

All correct

Aspergillus niger: otitis externa (otomycosis) phialides with conidia covering entire vesicle surface black peppered rapidly growing colony hyphae hyaline and septate

all of these answers

Certain inherent or induced conditions may predispose a patient to fungal infection from a zygomycete. These conditions may include: antineoplastic drugs antibiotic therapy all of these answers immunosuppression

at least 30 days

Fungal cultures should be held for how many days before being discarded as negative: 14 days 7 days at least 30 days 3 days

a b d g h

HI is agar that is used to grow fungi. What is this media usually enriched with? a. Blood b. Gentamicin c. Vancomycin. d. cycloheximide e. Glitter f. Penicillin g. Chloramphenicol h. Blood

pastel colored colonies

Hyaline saprophytic molds demonstrate which one of the following characteristics: yellow or brown hyphae pastel colored colonies slow growing sporangia

frozen

If the culturing of a fungal specimen is delayed, the specimen should never be: incubated at 35o C refrigerated frozen held at room temperature

a and b

Microscopic appearance of Aspergillus niger: a.sporulation all around vesicle b.conidia in chains c.most common cause of aspergillosis d.phialides in single row

Aspergillus

Septate hyaline hyphae and a young conidiophore terminating in a swollen vesicle are distinguishing characteristics for which one of the following molds; Absidia Mucor Aspergillus Rizopus

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: Microsporum canis Epidermophyton floccosum Microsporum gypseum Trichophyton rubrum

Fusarium spp.

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: Aspergillus spp. Paecilomyces spp. Penicillium spp. Fusarium spp.

contains a lower dextrose concentration

The Sabouraud's agar with Emmon's modification differs from conventional Sabouraud's agar because it: inhibits bacteria contains antibiotics has an acid pH contains a lower dextrose concentration

Aspergillus

The genus of hyaline mold that causes the majority of human disease is: Penicillium Fusarium Scedosporium Aspergillus

d

The hyaline mold Fusarium species has been implicated in corneal ulcers and mycetomas. The colony morphology and microscopic characteristics most closely resemble which of the following: a.Slow grower that is gray-brown and produces macroconidia in chains b.Rapid grower "lid lifer" that produces aseptate hyphae with nodal rhizoids c.Slow grower that is granular and light tan, with an orange-colored reverse, and abundant macroconidia d.Rapid grower that usually produce a lavender pigment and crescent-shaped, septate macroconidia

Aspergillus terreus

The photomicrograph shown below was taken from a rapidly growing cinnamon brown mold with a granular surface. The image to the right is a squash prep of the colony. This organism most likely is: Penicillium marneffei Scopulariopsis sp. Aspergillus terreus Aspergillus fumigatus

skin

The potassium hydroxide direct mount technique is most commonly used to examine which of the following specimens: Subcutaneous aspirate CSF Bone marrow Skin

a b d e

The stains that are used most commonly to stain fungal elements are: a. India ink b. Lactophenol-aniline blue c.Wright Stain d.Gram stain e. KOH f.Methylene blue

Arthroconidia

These conidia are formed by fragmentation of fertile hyphae. Annelloconidia Phialoconidia Arthroconidia Blastoconidia

Ascus

This is a sac-like structure in which sexual spores are produced. Sporangium Rhizoid Annellide Ascus

Mucor spp

This organism was isolated from a diabetic patient with a sinus infection. The mold was extremely fast growing with a dirty white surface. Microscopic observation revealed wide sparsely septate (aseptate) hyphae without rhizoids. This organism is most likely Mucor spp Malassezia furfur. Microsporum spp. Sporothrix schenckii.

Moniliaceous

This type of hyphae are not pigmented. Phaeoid Mycelia Dematiaceous Moniliaceous

All

Trichophyton is known to invade which of the following: Skin all of the choices Hair Nails

d

Two species of Trichophyton produce colonies on potato dextrose agar plates that are similar in color and appearance. The hair baiting test is used to differentiate which two organisms: a. T. verrucosum and T. rubrum b. T. tonsurans and T. schoenleinii c. T. tonsurans and T. mentagrophytes d. T. mentagrophytes and T. rubrum

Zygomycetes

Which of the following groups of mold possess aseptate hyphae? Zygomycetes Dematiaceous molds Hyaline molds Deramtophytes

Swab

Which of the following is the least acceptable specimen for fungal culture Aspirate of exudate Swab CSF Tissue biopsy

30C

Which of the following temperatures should fungal cultures be incubated: 30C 2-4 C 56 C 37C

Absidia

the location of the rhizoids is the major clue in the differentiation of Rhizopus from: Absidia Mucor Syncephalastrum Circinella Cunninghamella