Deck 22: Pathogenic Fungi

Question 1

Which of the following contributes to the pathogenesis of Cryptococcus neoformans?

A) the production of mucinase
B) the ability to produce hyphae which penetrate tissues
C) the production of melanin and the presence of a phagocyte- resistant capsule
D) the production of leukocidins
E) the ability to resist killing after phagocytosis

Answer 1

C

Question 2

An elderly woman is experiencing fever, chest pain, difficulty breathing, and a cough that occasionally brings up mucus containing blood. She reports having visited family in rural New Mexico over the Labor Day weekend. A GMS- stained sample from her lungs shows the presence of large spherules. Which of the following is the most likely infecting agent?

A) Paracoccidioides brasiliensis
B) Histoplasma capsulatum
C) Trichophyton rubrum
D) Coccidioides immitis
E) Blastomyces dermatitidis

Answer 2

D

Question 3

Which of the following dermatophytes infects hair as well as skin?

A) Microsporum canis
B) Epidermophyton floccosum
C) Malassezia furfur
D) Trichophyton rubrum
E) Fonsecaea pedrosoi

Answer 3

D

Question 4

An avid gardener in eastern North America begins to have a fever and cough. A sample from her lungs contains yeast cells. She may be infected with

A) Blastomyces dermatitidis.
B) Paracoccidioides brasiliensis.
C) Mucor.
D) Amanita phalloides.
E) Claviceps purpurea.

Question 5

The monomorphic fungus Rhizopus is a(n)

A) true pathogen.
B) toxic mushroom.
C) opportunistic pathogen.
D) common bread mold.
E) common bread mold and an opportunistic pathogen.

Question 6

Which of the following produces a hallucinogenic toxin?

A) Claviceps purpurea
B) Paracoccidioides brasiliensis
C) Amanita phalloides
D) Pseudallescheria
E) Psilocybe cubensis

Question 7

The fungus produces toxins which have beneficial clinical applications.

A) Amanita phalloides
B) Rhizopus
C) Aspergillus flavus
D) Epidermophyton floccosum
E) Claviceps purpurea

Question 8

Which of the following statements is true of mycotoxicosis but NOT mycetismus?

A) The portal of entry is the mouth.
B) It causes toxicosis.
C) The fungus is not present.
D) Organ damage can result.
E) Mushrooms are ingested.

Question 9

Chronic inhalation of particular fungal allergens would lead to a(n)

A) type I hypersensitivity reaction.
B) autoimmune disease.
C) type III hypersensitivity reaction.
D) type IV hypersensitivity reaction.
E) type II hypersensitivity reaction.

Question 10

Most mycoses are difficult to treat because

A) fungicides have numerous side effects, including cross- reactivity to human cells.
B) fungicides have numerous side effects.
C) fungal cells are similar to human cells.
D) many fungi have developed resistance antifungal agents.
E) many fungi have developed resistance antifungal agents and fungicides have numerous side effects.

Question 11

Injuries which introduce _ into the subcutaneous tissue may result in mycetoma, a tumor- like abscess containing pus and fungus.

A) Blastomyces dermatitidis
B) Sporothrix schenckii
C) Coccidioides immitis
D) Pseudallescheria
E) Histoplasma capsulatum

Question 12

Which of the following fungal infections may progress to infection of the brain?

A) Mucor
B) Coccidioides immitis
C) Cryptococcus neoformans
D) both Coccidioides immitis and Cryptococcus neoformans
E) Coccidioides immitis, Cryptococcus neoformans, and Mucor

Question 13

Psilocybin is a

A) virulence factor produced by bacteria.
B) growth factor produced by mycoplasmas.
C) toxin that causes bloody diarrhea.
D) toxin that causes kidney failure.
E) toxin that acts as a hallucinogen.

Question 14

Pityriasis, characterized by patches of hyperpigmented and depigmented skin on the trunk and arms, is due to cutaneous infection with

A) Malassezia furfur.
B) Epidermophyton floccosum.
C) Microsporum canis.
D) Trichophyton rubrum.
E) Cryptococcus neoformans.

Question 15

An immunocompromised patient has a severe nasal infection that has blocked his ability to breathe through his nose. A sample taken from the nose is treated with KOH and is found to contain large hyphae with very few septa. Which of the following diseases may the patient have?

A) mycetoma
B) zygomycosis
C) candidiasis
D) cryptococcosis
E) blastomycosis

Question 16

Which of the following statements about Candida is FALSE?

A) It can be transmitted to adults during sexual contact.
B) It is present in the digestive tract of 40- 80% of all healthy individuals.
C) It causes thrush.
D) It can be passed to babies during childbirth.
E) It is easily treated with topical antifungals in immunocompromised patients.

Question 17

Which of the following statements about truly pathogenic fungi that cause systemic mycoses is FALSE?

A) They are relatively resistant to phagocytic killing.
B) They produce yeast forms at 37°C.
C) They can infect any susceptible host regardless of its immune status.
D) They are dimorphic.
E) They have the ability to form mycelial thalli that are very invasive.

Question 18

Superficial mycoses are more common than cutaneous and subcutaneous mycoses because

A) only a few fungi are invasive.
B) the human body is a toxic environment for fungi.
C) only immunocompromised persons are susceptible to subcutaneous mycoses.
D) there are far more fungi that cause superficial mycosis than the ones that cause cutaneous and subcutaneous infections.
E) the surface of the body is constantly bombarded by fungal spores.

Question 19

Which of the following fungal infections can be contracted through thorn pricks or wood splinters?

A) Sporothrix schenckii
B) Cladophialophora bantiana
C) Aspergillus flavus
D) Gyromitra esculenta
E) Malassezia furfur

Question 20

Chronic low- level ingestion of may cause liver cancer.

A) aspergillin
B) phalloidin
C) aflatoxin
D) ergotamine
E) psilocybin

Question 21

Which of the following is the most common pathogenic fungus affecting humans?

A) Paracoccidioides brasiliensis
B) Aspergillus fumigatus
C) Coccidioides immitis
D) Histoplasma capsulatum
E) Blastomyces dermatitidis

Question 22

Which of the following techniques reveal(s) the presence of fungal cells in tissues?

A) Gram staining combined with KOH treatment
B) Gomori methenamine silver (GMS) staining
C) Gram staining
D) KOH treatment
E) both KOH treatment and Gomori methenamine silver (GMS) staining

Question 23

Ringworm is caused by

A) dermatophytes growing in the outer dead tissue layers of the skin (epidermis).
B) toxins produced by dermatophytes.
C) dermatophytes that have invaded deep into the living tissue.
D) worms infected with fungi invading the skin.
E) a hypersensitivity caused by superficial contact with dermatophytes.

Question 24

A sample of the tissue from an inflamed, pus- filled area on the lower leg is treated with KOH and stained with GMS. Under the microscope golden brown spheres are visible. With what disease are these observations consistent?

A) pityriasis
B) fungemia
C) mycetoma
D) sporotrichosis
E) chromoblastomycosis

Question 25

Which of the following agars is preferred for the culture of fungi?

A) chocolate agar
B) Sabouraud dextrose agar
C) MacConkey agar
D) Thayer- Martin media
E) sheep blood agar

Question 26

Which of the following is a false morel that causes bloody diarrhea, convulsions, and death within two days?

A) Amanita phalloides
B) Aspergillus flavus
C) Mucor
D) Gyromitra esculenta
E) Sporothrix schenckii

Question 27

Ocular histoplasmosis is a(n)

A) cytotoxic immune cell reaction.
B) autoimmune disease.
C) type I hypersensitivity immune reaction.
D) delayed hypersensitivity reaction.
E) example of contact dermatitis.

Question 28

The most common disease produced in humans by Cryptococcus is

A) secondary pulmonary cryptococcosis.
B) cryptococcal meningitis.
C) cutaneous cryptococcosis.
D) primary pulmonary cryptococcosis.
E) cryptococcoma.

Question 29

Ergometrine, which is used to stimulate labor contractions, is a product of

A) Exophiala.
B) Piedraia hortae.
C) Claviceps purpurea.
D) Amanita phalloides.
E) Aspergillus flavus.

Question 30

Histoplasma capsulatum

A) produces yeast cells with a "steering wheel" formation.
B) produces arthrospores.
C) produces capsules.
D) is an opportunistic fungus.
E) is an intracellular parasite.

Question 31

Infection of the skin by Trichophyton rubrum results in raised red scaly patches of skin, a condition known as

A) candidiasis.
B) dermatophytosis.
C) pityriasis.
D) sporothrichosis.
E) mucormycosis.

Question 32

Mycetismus is caused by

A) ingestion of milk from a cow that has ingested feed contaminated with fungal toxins.
B) contamination of a wound with pathogenic fungi present in the skin.
C) ingestion of toxic mushrooms.
D) inhalation of allergy causing fungi.
E) ingestion of food contaminated with fungus.

Question 33

All of the true pathogen fungi mentioned in this chapter are

A) members of the Zygomycota and are monomorphic.
B) members of the Ascomycota.
C) members of the Zygomycota.
D) dimorphic.
E) members of the Ascomycota and are dimorphic.

Question 34

What is the diagnostic structure produced by Paracoccidioides brasiliensis?

A) "steering wheel" or "captain's wheel" buds visible microscopically
B) spiny spores
C) dimorphism when grown in the lab
D) yeast buds that are not dissolved by KOH
E) spherules

Question 35

Opportunistic fungi

A) have the same geographical distribution as pathogenic fungi.
B) always have two physiological and structural forms.
C) are normal microbiota for many individuals.
D) are not tracked by epidemiologists.
E) have special proteins for colonizing the body.

Question 36

The subcutaneous infection known as can produce a series of lesions spreading from the initial infection point resulting from the fungus' ability to invade the lymphatic vessels.

A) sporotrichosis
B) zygomycosis
C) candidiasis
D) aspergillosis
E) mycetoma

Question 37

Which of the following fungal infections was rare prior to the AIDS epidemic?

A) pulmonary cryptococcosis
B) Pneumocystis pneumonia
C) mycetomas
D) hypersensitivity aspergillosis
E) cutaneous candidiasis

Question 38

Pneumocystis jiroveci is

A) an obligate parasite that cannot survive outside the lungs.
B) easy to grow in the laboratory.
C) a common member of the human respiratory microbiota.
D) not a danger to AIDS patients.
E) actually a protozoan and not a fungus.

Question 39

Agricultural workers may develop respiratory problems resulting from responses to fungal allergens.

A) type I hypersensitivity
B) type II hypersensitivity
C) either type I or type III hypersensitivities
D) toxemia
E) type III hypersensitivity

Question 40

Brown pigmented hyphae in specimens from cutaneous or subcutaneous lesions are characteristic of

A) phaeohyphomycosis.
B) pityriasis.
C) mycetoma.
D) chromoblastomycosis.
E) sporotrichosis.

Question 41

The true pathogenic fungi responsible for systemic mycoses have (dimorphic/monomorphic/polymorphic) growth characteristics.

Question 42

The antifungal agent (azole/echinocandins/griseofulvin) interferes with microtubule formation and chromosome separation.

Question 43

Paracoccidioidomycosis occurs in Mexico and (North/South) America.

Question 44

The opportunistic infection known as (aspergillosis/cryptococcosis/sporotrichosis) may develop into a series of nodular, pus- filled lesions on a limb.

Question 45

Which of the following is an opportunistic pathogenic fungus in humans?

A) Blastomyces dermatitidis
B) Histoplasma capsulatum
C) Candida albicans
D) Coccidioides immitis
E) Paracoccidioides brasiliensis

Question 46

Several new fungal opportunists have been found to infect AIDS patients including

A) Saccharomyces cerevisiae.
B) Trychophyton.
C) Blastomyces dermatitidis.
D) Penicillium marneffei.
E) Amanita phalloides.

Question 47

Most fungi exist as (parasites/saprobes/autotrophs) and function as the major decomposers of organic material.

Question 48

The best strategy for preventing fungal disease is (avoidance/vaccination).

Question 49

Which of the following statements about Malassezia is FALSE?

A) It causes phaeohyphomycosis.
B) It is part of the microbiota of the skin.
C) It tends to develop into a chronic infection.
D) It is a basidomycete.
E) It causes pityriasis.

Question 50

The production of distinctively (smooth/bumpy/spiny) spores is diagnostic for Histoplasma capsulatum.

Question 51

The cell walls of fungi contain (cholesterol/ergosterol) which is a target of some antifungal treatments.

Question 52

Exposure to (Aspergillus/Candida/Microsporum) species most commonly causes only allergies.

Question 53

Which of the following is referred to as the "death cap" mushroom?

A) Gyromitra esculenta
B) Amanita phalloides
C) Psilocybe cubensis
D) Amanita muscaria
E) Cortinarius gentilis

Question 54

The presence of (hyphae/spores/spherules) in a sample from the lungs is diagnostic for coccidioidomycosis.

Question 55

Clusters of budding yeast and branching pseudohyphae are consistent with (candidiasis/dermatophytosis/pityriasis).

Question 56

A solution of (GMS/KOH/DIF) is used to dissolve keratin and cellular material in skin scrapings, leaving only the fungal cells for examination.

Question 57

White patches on the surface of the tongue and the oral mucosa accompanied by inflammation and swelling are signs consistent with

A) thrush.
B) coccidioidomycosis.
C) aspergillosis.
D) sporotrichosis.
E) cryptococcosis.

Question 58

Blastomyces dermatitidis occurs in the (eastern/central/southwestern/western) part of North America.

Question 59

Chronic infections of Malassezia furfur result in (pityriasis/ringworm).

Question 60

Infections with (dermatophytes/pathogens/opportunists) are commonly acquired by person- to- person direct contact.

Question 61

Systemic infections with fungus are difficult to treat because fungi are metabolically similar to humans, so antifungal therapies are sometimes complicated by side effects.

Question 62

Severe mycetismus may require a liver transplant.

Question 63

Compare and contrast dermatophytosis and pityriasis.

Question 64

More fungal diseases are recognized than were known just a decade ago. For example, in 2012 hundreds of patients developed a meningitis caused by a fungus never before known to cause disease. What contributes to these emerging diseases?

Question 65

Hypersensitivity aspergillosis is a form of cutaneous infection with Aspergillus.

Question 66

Griseofulvin is an effective antifungal with no lasting side effects.

Question 67

Histoplasma and Coccidioides produce tuberculosis- like damage to the lungs that can be seen on X- ray images.

Question 68

The seriousness of Coccidioides infection can be attributed to the formation and rupture of spherules.

Question 69

Why are mycoses among the most difficult diseases to treat?

Question 70

Distinguish mycotoxicosis from mycetismus.

Question 71

A man has difficulty breathing, a cough, and is running a fever. He is an avid bird- watcher who recently visited a rookery where thousands of birds build their nests and raise their young. What fungal infection(s) might he have contracted? What diagnostic tests would confirm the diagnosis? What treatment might be prescribed?

Question 72

Very few cases of cryptococcal infections are caused by the variant Cryptococcus neoformans neoformans.

Question 73

Fungi that cause systemic mycoses are uniformly acquired by ingesting contaminated food.

Question 74

Vaccines to prevent fungal infection are widely available because attenuated strains are safe.

Question 75

Dermatophytes, which live on the surface of the skin, are always pathogenic.