Advanced Clinical Mycology

A bulldozer operator became ill while working on a new highway in the San Joaquin Valley. He developed chest pain, anorexia, headache and general malaise, and myalgia with fever. Chest x-ray showed pneumonic infiltrate and a single, well-defined nodule in the left lower lobe. His leukocyte count and sedimentation rate were slightly elevated. Although no fungus was seen in direct examination of a sputum specimen, processing included a culture on Sabouraud's dextrose agar with chloramphenicol and cycloheximide. Within 3 days at 28°C this culture produced moist, grayish growth, and a white aerial mycelium began to develop. If this fungus was the cause of infection, it was most probably:

Asperigillus fumigatus

Blastomyces dermatitidis

Coccidioides immitis

Cryptococcus neoformans

Histoplasma capsulatum

coccidioides immitis

The formation of arthroconidia is a characteristic important in the identification of all of the following, except:

Coccidioides

Geotrichum

Trichosporon

Sporothrix

Aureobasidium

Sporothrix

A blood agar plate inoculated with sputum from a patient with diabetes mellitus grew very few bacterial flora and a predominance of yeast. Given the following results what is the most likely identification of the yeast isolate?
Cornmeal Tween 80 Agar
Germ tube = NegPseudohyphae = Pos
Arthrospores = NegBlastoconidia = + (arranged as 'logs in a stream')
Chlamydospores = Neg

C. tropicalis

C. kefyr

Trichosporon beigelii

Geotrichum candidum

C. albicans

C. tropicalis

Chronic mucocutaneous candidiasis (CMCC) in children is associated with genetic defects in cellular immunity. Which of the following syndromes has been found to predispose to CMCC?

Flu

Hepatitis syndrome

DiGeorge's syndrome (with absence of thymus)

Bruton's hypogammaglobulinemia (humoral immunity deficiency)

Diarrhea syndrome

DiGeorge’s syndrome with absence of thymus

The microscopic identification of Pneumocystis jirovecii is based on the detection of:

Arthroconidia in subcutaneous tissue biopsies

Cysts and trophozoites in respiratory specimens

Yeasts in respiratory specimens

Tuberculate macroconidia in lung biopsies

Conidia in respiratory specimens

Cysts and trophozoites in respiratory specimens

In tissues infected with Histoplasma capsulatum:

The hyphae usually invade blood vessels

Encapsulated yeast cells are typical

Tuberculate macroconidia are typical

The fungus is usually intracellular

Fungal organisms are not detectable

the fungus is usually intracellular

For each numbered mycosis below, choose the lettered environment most commonly associated with an increased incidence of that infection.

Blastomycosis

coccidioidomycosis

crytococcosis

histoplasmosis

sporotrichosis

Pigeon roosts

mississippi and ohio river basins

lower sonoran life zone

starling roosts

sphagnum moss

Histoplasmosis-starling roosts

sporotrichosis-sphagnum moss

blastomycosis- Mississippi and Ohio river basins

coccidioidomycosis- lower sonoran life zone

crytococcosis- pigeon roosts

The incomplete statements below describe the appearance of growth of yeast or yeast-like fungi in morphology agar, such as rice agar or cornmeal agar with Tween 80, a finding helpful in the presumptive identification of these organisms. For each numbered description, select the most appropriate lettered species.

True hyphae and arthrospores only

true hyphae, arthrospores, and blastospores

pseudohyphae, blastospores, and chlamydospores

pseudohyphae and blastospores only

blastospores only, without hyphae or pseudohyphae

crytococus neoformans

trichosporon

candida tropicalis

candidat albicans

geotrichum

Pseudohyphae, blastospores, and chlamydospores- candida albicans

pseudohyphae and blastospores only- candida tropicalis

blastospores only, without hyphae or pseudohyphae- cryptococcus neoformans

true hyphae, arthrospores, and blastospores-trichosporon

true hyphae and arthrospores only-geotrichum

A black pigment produced by colonies growing on bird seed agar is due to:

Urease

Phenol oxidase

Sucrose assimilation

Arthroconidia production

Glucose assimilation

Phenol oxidase

Which of the following is likely to be found in clinical specimens as normal microflora and as clinically significant isolates?

Aspergillus niger

Scopulariopsis

Penicillium notatum

Candida albicans

Fusarium

Candida albicans

For each incomplete statement, select the most appropriate lettered species.

the cause of white piedra

the cause of black piedra

the cause of tinea nigra

the cause of pityriasis (tinea) versicolor

a keratinophilic saprophyte

Trichosporon beijelii

malassezia furfur

trichophyton ajelloi

exophiala werneckii

piedraia hortae

the cause of white piedra-trichosporon beigelii

The cause of tinea nigra- exophiala werneckii

The cause of pityriasis (tinea) versicolor- malassezia furfur

the cause of black piedra- piedraia hortae

A keratinophilic saprophyte- trichophyton ajelloi

Although Candida albicans is the species most often found in clinical candidiasis, other species are more frequently isolated from Candida endocarditis. The more common etiologic agent of this syndrome is:

C. tropicalis

C. glabrata

C. pseudotropicalis

C. parapsilosis

C. famata

C. parapsilosis

Host conditions that are associated with an increased incidence of Candida albicans infections include all of the following, except:

Diabetes

Childhood viral infections

Prolonged antibiotic usage

Pregnancy

Use of immunosuppressive agents

childhood viral infections

Identify the dimorphic fungus that typically has a tissue phase in which the large mother cells have one to a dozen narrow-necked buds and slow-growing mycelial form with intercalary chlamydoconidia and coiled hyphae.

Blastomyces dermatitidis

Coccidioides immitis

Histoplasma capsulatum

Paracoccidioides brasiliensis

Sporothrix schenckii

paracoccidioides brasiliensis

Observation of hyaline or dematiacious hyphae is an early clue in the identification of common, airborne fungi. Which of the following genera contains species found as dematiacious contaminants?

Alternaria

Penicillium

Paecilomyces

Fusarium

Scopulariopsis

alternaria

A fungus infecting only skin and nails typically produces in culture:

Spindle-shaped, hyaline, echinulate macroconidia and microconidia

Cylindrical or club-shaped, smooth thin-walled macroconidia and microconidia

Many microconidia in clusters or along the hyphae

Large, thin-walled, club-shaped conidia without microconidia

Racquet and spiral hyphae without conidia

Large, thin-walled, club-shaped conidia without microconidia

Broad, coenocytic hyphae found in tissue would be most typical of infection with:

Aspergillus

Blastomyces

Microsporum

Nocardia

Rhizopus

Rhizopus

Trichophyton rubrum and Trichophyton mentagrophytes may be differentiated by the:

Consistently different appearance of their colonies

Endothrix hair infection produced by T. rubrum

Fluorescence of hairs infected with T. rubrum

In vitro hair penetration by T. mentagrophytes

Production of urease by T. rubrum

in vitro hair penetration by T. mentagrophytes

Which of the following species of fungus is usually encapsulated and urease positive and typically produces mucoid, red colonies?

Crytococcus neoformans

Rhodotorula rubra

Saccharomyces cerevisiae

Trichophyton rubrum

Trichosporon beigelii

Rhodotorula rubra

Five types of fungal structures are given below. Which of these is not produced by causative agents of chromomycosis?

a

b

c

d

e

A 69-year-old male patient who was a cigarette smoker visited the doctor's office complaining of a cough and congestion of the lungs. Routine cultures of early morning sputum (x3) for bacteria as well as for AFB revealed no pathogens. A fungal culture was also ordered that grew the following on Sabouraud dextrose agar after 3 days.
Hyphae = septate with dichotomous branching
Spores = produced by conidial heads with numerous conidia
Colonies = velvety or powdery, white then turning dark green to gray (reverse = white to tan)
Vesicle = holding phialides usually on upper two-thirds only
What is the most likely identification?

Aspergillus niger

Absidia spp.

Mucor spp.

Aspergillus fumigatus

Candida tropicalis

aspergillus fumigatus

The most useful finding for prompt, presumptive identification of C. albicans is its:

Failure to assimilate sucrose

"Feathering" on EMB

Production of chlamydoconidia

Production of germ tubes

Production of pseudohyphae

Production of germ tubes

A yeast-like fungus was isolated from sputum. No hyphae were produced in morphology agar. It was negative for nitrate assimilation and positive for inositol assimilation and produced urease at 37°C. These findings are typical of:

Candida krusei

Cryptococcus terreus

Cryptococcus neoformans

Trichosporon beigelii

Geotrichum candidum

cryptococcus neoformans

Select the most appropriate lettered specimen source for isolation of each numbered species.

Aspergillus niger

cryptococcus neuformans

histoplasma capsulatum

pseudallescheria boydii

trichophyton mentagrophytes

Chronic interdigital lesion of foot

otitis externa

cerebrospinal fluid

bone marrow

chronic draining sinus tract of foot

Cryptococcus neoformans- cerebrospinal fluid

histoplasma capsulatum- bone marrow

pseudallescheria boydii- chronic draining sinus tract of foot

aspergillus niger- otitis externa

trichophyton mentagrophytes- chronic interdigital lesion of foot

Large, one-celled, smooth to tuberculate macroconidia and smooth or echinulate microconidia are typical of mycelial phase growth of:

Bastomyces dermatitidis

Coccidioides immitis

Histoplasma capsulatum

Paracoccidioides brasiliensis

Sporothrix schenckii

Histoplasma capsulatum

Quesiton was weird

Fungi considered to be opportunistic pathogens include all of the following, except:

Absidia

Aspergillus

Coccidioides

Fusarium

Rhizopus

coccidioides

The location of the sporangiophores in relation to the rhizoids is the major clue in the differentiation of Rhizopus from:

Absidia

Circinella

Cunninghamella

Mucor

Syncephalastrum

Absidia

Which of the following types of Candida albicans infection is commonly acquired from an exogenous source?

Diaper rash

Neonatal thrush

Perianal infection

Urinary tract infection

Vulvovaginitis

Neonatal thrush

A rose gardener pricked himself with a contaminated thorn. A subcutaneous fungal infection characterized by the development of necrotic ulcers followed this direct inoculation of fungal spores into the skin. The causative fungus was cultured as a small yeast form at 36°C and as a mold at room temperature with delicate hyphae and conidia. This disease is:

Blastomycosis

Chromomycosis

Mycetoma

Sporotrichosis

Tinea

sporotrichosis

Weird again

Several children in a second-grade classroom developed tinea capitis. Under a Woods' lamp, their infected hairs showed green fluorescence. Cultures of these hairs grew fungi with aerial mycelia and terminal chlamydospores. These isolates were most probably:

Candida albicans

Epidermophyton floccosum

Microsporum audouinii

Microsporum gypseum

Trichophyton rubrum

Microsproum audouinii

All of the following statements correctly describe the yeast Rhodotorula rubra, except:

It has been isolated from dairy products, air, soil, and water

It is the most common fungal cause of diaper rash

It has been identified as a nosocomial pathogen

It has been found as a contaminant or commensal in specimens of urine, sputum, and feces

It has been found to cause endotoxic shock

It is the most common fungal cause of diaper rash. Rhodotorula are environmental organisms in the soil, air, foods, and some dairy products. Candida albicans is the primary fungal cause of diaper rash.

It is usually difficult or impossible to identify a fungal culture before it is mature. However, the presence of hyaline, septate hyphae, and a young conidiophore with a foot cell and a swollen vesicle are excellent clues to the identification of:

Scopulariopsis

Aspergillus

Paecilomyces

Penicillium

aspergillus

Which of the following stains greatly enhances the visibility of fungi by binding to the cell walls, causing the fungi to fluoresce blue-white or apple green?

Rhodamine-auramine

Warthin-Starry

Calcofluor white

Periodic acid-Schiff

Acridine orange

Calcofluor white

Conversion of the myelial phase to the tissue phase is especially important in differentiating certain dimorphic pathogens from saprophytes that resemble them. These "look-alike" pairs include:

Blastomyces and Chrysosporium

Coccidioides and Paracoccidioides

Histoplasma and Scopulariopsis

Trichosporon and Sporothrix

Fusarium and Coccidioides

blastomyces and chrysosporium

Which of the following fungi is most likely to be found as a common saprobe and as an agent of keratitis?

Exophiala

Phialophora

Fusarium

Wamgiella
b.Sporothrix

Fusarium

Zygomycetes are fast-growing, airborne saprobes. In clinical specimens they:

Are common as normal, human microflora

Are found only as contaminants

May be seen in a dimorphic tissue phase

May be found as a cause of rapidly fatal infection

May be found as a cause of tinea

May be found as a cause of rapidly fatal infection