Term
Which of the following is an opportunistic pathogenic fungus in humans?
A) Blastomyces dermatitidis
B) Coccidioides immitis
C) Candida albicans
D) Histoplasma capsulatum
E) Paracoccidioides brasiliensis |
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Definition
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Term
Opportunistic fungi
A) have two physiological and structural forms.
B) are normal microbiota for many individuals.
C) have special proteins for colonizing the body.
D) are carefully tracked by epidemiologists.
E) have the same geographical distribution as pathogenic fungi. |
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Definition
| B) are normal microbiota for many individuals. |
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Term
Which of the following statements about pathogenic fungi is FALSE?
A) They are dimorphic.
B) They have the ability to form mycelial thalli that are very invasive.
C) They produce yeast forms at 37°C.
D) They can infect any susceptible host regardless of its immune status.
E) They are relatively resistant to phagocytic killing |
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Definition
| B) They have the ability to form mycelial thalli that are very invasive. |
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Term
Which of the following agars is preferred for the culture of fungi?
A) Sabouraud dextrose agar
B) sheep blood agar
C) MacConkey agar
D) chocolate agar
E) Thayer-Martin media |
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Definition
| A) Sabouraud dextrose agar |
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Term
Which of the following techniques reveal(s) the presence of fungal cells in tissues?
A) Gram staining
B) KOH treatment
C) Gomori methenamine silver (GMS) staining
D) Gram staining combined with KOH treatment
E) KOH treatment and Gomori methenamine silver (GMS) staining |
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Definition
| E) KOH treatment and Gomori methenamine silver (GMS) staining |
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Term
The most common pathogenic fungus affecting humans is
A) Blastomyces dermatitidis.
B) Coccidioides immitis.
C) Histoplasma capsulatum.
D) Paracoccidioides brasiliensis.
E) Aspergillus fumigatus |
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Definition
| C) Histoplasma capsulatum. |
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Term
Mycoses are difficult to treat because
A) many fungi have developed resistance antifungal agents.
B) fungicides have numerous side effects.
C) fungal cells are similar to human cells.
D) many fungi have developed resistance antifungal agents and fungicides have numerous side effects.
E) fungicides have numerous side effects and fungal cells are similar to human cells. |
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Definition
| E) fungicides have numerous side effects and fungal cells are similar to human cells. |
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Term
All of the true pathogen fungi
A) are members of the Ascomycota.
B) are members of the Zygomycota.
C) are dimorphic.
D) are members of the Ascomycota and are dimorphic.
E) are members of the Zygomycota and are monomorphic. |
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Definition
| D) are members of the Ascomycota and are dimorphic. |
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Term
Ocular histoplasmosis is
A) a type I hypersensitivity immune reaction.
B) a cytotoxic immune cell reaction.
C) a delayed hypersensitivity reaction.
D) an autoimmune disease.
E) an example of contact dermatitis |
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Definition
| A) a type I hypersensitivity immune reaction. |
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Term
What is the diagnostic structure produced by Paracoccidioides brasiliensis?
A) spiny spores
B) "steering wheel" buds
C) spherules
D) yeast buds that are not dissolved by KOH
E) dimorphism when grown in the lab |
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Definition
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Term
A young 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) Coccidioides immitis
B) Blastomyces dermatitidis
C) Histoplasma capsulatum
D) Paracoccidioides brasiliensis
E) Trichophyton rubrum |
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Definition
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Term
Which of the following statements about Candida is FALSE?
A) It is present in the digestive tract of 40—80% of all healthy individuals.
B) It can be transmitted to adults during sexual contact.
C) It is easily treated with topical antifungals in immunocompromised patients.
D) It causes thrush.
E) It can be passed to babies during childbirth |
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Definition
| C) It is easily treated with topical antifungals in immunocompromised patients. |
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Term
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) Amanita phalloides.
B) Blastomyces dermatitidis.
C) Claviceps purpurea.
D) Mucor.
E) Paracoccidioides brasiliensis |
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Definition
| B) Blastomyces dermatitidis. |
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Term
The most common disease produced in humans by Cryptococcus is
A) primary pulmonary cryptococcosis.
B) cryptococcal meningitis.
C) secondary pulmonary cryptococcosis.
D) cryptococcoma.
E) cutaneous cryptococcosis. |
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Definition
| B) cryptococcal meningitis. |
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Term
Which of the following fungal infections was rare prior to the AIDS epidemic?
A) pulmonary cryptococcosis
B) cutaneous candidiasis
C) hypersensitivity aspergillosis
D) mycetomas
E) Pneumocystis pneumonia |
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Definition
| E) Pneumocystis pneumonia |
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Term
Pneumocystis jiroveci is
A) easy to grow in the laboratory.
B) actually a protozoan and not a fungus.
C) an obligate parasite that cannot survive outside the lungs.
D) a common member of the human respiratory microbiota.
E) not a danger to AIDS patients. |
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Definition
| C) an obligate parasite that cannot survive outside the lungs. |
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Term
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) candidiasis
B) blastomycosis
C) cryptococcosis
D) mycetoma
E) zygomycosis |
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Definition
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Term
What is the diagnostic feature of Trichosporon beigelii?
A) the presence of soft white to gray nodules
B) the presence of cotton-wool colonies in the nose
C) the production of melanin, which stains the cutaneous lesion brown-black
D) the presence of hard black nodules
E) the presence of the fungus growing in hair |
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Definition
| A) the presence of soft white to gray nodules |
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Term
Ringworm is caused by
A) worms infected with fungi invading the skin.
B) dermatophytes that have invaded deep into the living tissue.
C) dermatophytes growing in the upper dead tissue layers of the skin.
D) a hypersensitivity caused by superficial contact with dermatophytes.
E) toxins produced by dermatophytes |
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Definition
| C) dermatophytes growing in the upper dead tissue layers of the skin. |
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Term
Histoplasma capsulatum
A) is an opportunistic fungus.
B) produces arthrospores.
C) produces capsules.
D) produces yeast cells with a "steering wheel" formation.
E) is an intracellular parasite. |
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Definition
| E) is an intracellular parasite. |
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Term
Which of the following dermatophytes infects hair as well as skin?
A) Microsporum canis
B) Malassezia furfur
C) Fonsecaea pedrosoi
D) Epidermophyton floccosum
E) Trichophyton rubrum |
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Definition
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Term
White patches on the surface of the tongue and the oral mucosa accompanied by inflammation and swelling are signs consistent with
A) aspergillosis.
B) cryptococcosis.
C) coccidioidomycosis.
D) sporotrichosis.
E) thrush |
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Definition
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Term
Which of the following fungal infections may progress to infection of the brain?
A) Coccidioides immitis
B) Cryptococcus neoformans
C) Mucor
D) Coccidioides immitis and Cryptococcus neoformans
E) Coccidioides immitis, Cryptococcus neoformans, and Mucor |
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Definition
| E) Coccidioides immitis, Cryptococcus neoformans, and Mucor |
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Term
A tumor-like infection that produces an oily fluid containing fungal granules is known as a
A) mycetoma.
B) sclerotic body.
C) spherule.
D) thallus.
E) yeast sore. |
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Definition
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Term
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. What disease are these observations consistent with?
A) pityriasis
B) fungemia
C) chromoblastomycosis
D) mycetoma
E) sporotrichosis |
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Definition
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Term
Which of the following fungal infections can be contracted through thorn pricks or wood splinters?
A) Sporothrix schenckii
B) Cladophialophora bantiana
C) Malassezia furfur
D) Gyromitra esculenta
E) Aspergillus flavus |
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Definition
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Term
Which of the following statements about Malassezia is FALSE?
A) It is part of the microbiota of the skin.
B) It causes phaeohyphomycosis.
C) It is a basidomycete.
D) It causes pityriasis.
E) It tends to develop into a chronic infection |
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Definition
| B) It causes phaeohyphomycosis. |
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Term
The monomorphic fungus Rhizopus is
A) a common bread mold.
B) a toxic mushroom.
C) an opportunistic pathogen.
D) a true pathogen.
E) a common bread mold and an opportunistic pathogen. |
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Definition
| E) a common bread mold and an opportunistic pathogen. |
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Term
Mycetismus is caused by
A) ingestion of food contaminated with fungus.
B) ingestion of toxic mushrooms.
C) ingestion of milk from a cow that has ingested feed contaminated with fungal toxins.
D) inhalation of allergy causing fungi.
E) contamination of a wound with pathogenic fungi present in the skin. |
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Definition
| B) ingestion of toxic mushrooms. |
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Term
Which of the following is referred to as the "death cap" mushroom?
A) Amanita phalloides
B) Gyromitra esculenta
C) Psilocybe cubensis
D) Amanita muscaria
E) Cortinarius gentilis |
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Definition
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Term
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) Gyromitra esculenta
D) Sporothrix schenckii
E) Mucor |
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Definition
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Term
Ergometrine, which is used to stimulate labor contractions, is a product of
A) Claviceps purpurea.
B) Aspergillus flavus.
C) Amanita phalloides.
D) Exophiala.
E) Piedraia hortae |
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Definition
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Term
Which of the following statements is true of mycotoxicosis but NOT mycetismus?
A) The portal of entry is the mouth.
B) Mushrooms are ingested.
C) Organ damage can result.
D) It causes toxicosis.
E) The fungus is not present |
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Definition
| E) The fungus is not present |
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Term
Psilocybin is a
A) toxin that causes bloody diarrhea.
B) toxin that causes kidney failure.
C) toxin that acts as a hallucinogen.
D) virulence factor produced by bacteria.
E) growth factor produced by mycoplasmas |
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Definition
| C) toxin that acts as a hallucinogen. |
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Term
Chronic inhalation of particular fungal allergens would lead to
A) a type I hypersensitivity reaction.
B) a type II hypersensitivity reaction.
C) a type III hypersensitivity reaction.
D) a type IV hypersensitivity reaction.
E) an autoimmune disease. |
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Definition
| C) a type III hypersensitivity reaction. |
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Term
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Definition
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Term
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Definition
| Mycotoxin associated with liver cancer |
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Term
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Definition
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Term
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Definition
| Pulmonary infection following close contact with birds |
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Term
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Definition
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Term
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Definition
| Patches of hyperpigmented and depigmented skin on the trunk and arms |
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Term
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Definition
| Infection of the hair, nails, and skin |
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Term
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Definition
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Term
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Definition
| Produces a toxin that is used to treat migraine headaches |
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Term
| Griseofulvin is an effective antifungal with no serious side effects. T/F |
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Definition
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Term
| Dermatophytes, which live on the surface of the skin, are always pathogenic. T/F |
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Definition
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Term
| Fungi that cause systemic mycoses are uniformly acquired by ingesting contaminated food. T/F |
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Definition
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Term
| The seriousness of Coccidioides infection can be attributed to the formation and rupture of spherules. T/F |
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Definition
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Term
| In endemic regions of the United States, close to 90% of the population test positive for Histoplasma capsulatum.T/F |
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Definition
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Term
| Hypersensitivity to aspergillosis is due to the formation of ball-like fungal hyphae in the cavities produced by previous tuberculosis. T/F |
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Definition
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Term
| Histoplasma and Coccidioides produce filtrates on the lungs that can be seen on X-ray images. T/F |
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Definition
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Term
| Very few cases of cryptococcal infections are caused by the variant Cryptococcus neoformans. T/F |
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Definition
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Term
| Severe mycetismus may require a liver transplant. T/F |
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Definition
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Term
| Vaccines to prevent fungal infection are widely available. T/F |
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Definition
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Term
| Most fungi exist as ________ and function as the major decomposers of organic material. |
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Definition
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Term
| Infections with ________ are commonly acquired by person-to-person contact. |
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Definition
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Term
| Diagnosis of fungi may require culturing them at different temperatures to demonstrate their ________ growth characteristics. |
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Definition
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Term
| ________ dissolves keratin and cellular material in skin scrapings, leaving only the fungal cells for examination. |
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Definition
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Term
| Fungal cells can be stained black in tissue sections by using ________ stain. |
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Definition
| Gomori methenamine silver |
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Term
| Instead of cholesterol, the walls of fungi contain ________. |
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Definition
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Term
| The "gold standard" of antifungal agents is ________. |
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Definition
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Term
| The antifungal agent ________ interferes with microtubule formation and chromosome separation. |
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Definition
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Term
| The presence of ________ in a sample from the lungs is diagnostic for coccidioidomycosis. |
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Definition
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Term
| Histoplasma ________ is limited to Africa. |
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Definition
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Term
| The production of distinctively spiny spores is diagnostic for ________. |
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Definition
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Term
| Exposure to ________ species most commonly causes only allergies. |
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Definition
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Term
| ________ can be diagnosed when clusters of budding yeast and branching pseudohyphae are present along with correlated symptoms. |
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Definition
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Term
| Opportunistic infection with ________ may develop into a series of nodular, pus-filled lesions on a limb. |
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Definition
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Term
| Chronic infections of Malassezia furfur result in ________. |
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Definition
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Term
| Why are mycoses among the most difficult diseases to treat? |
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Definition
| There are two main reasons it is so difficult to treat mycoses. First, fungi possess the biochemical ability to resist killing by T lymphocytes during cell-mediated immune responses, making them resistant to the body's defenses. Second, fungi are eukaryotic cells and are very similar to human cells, so most antifungal agents are also toxic to human cells. |
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Term
| Why are most fungal infections not diagnosed by the indirect fluorescent antibody techniques? |
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Definition
| Because most fungi are so prevalent in the environment, and because many are part of the normal microbiota of the human body, demonstration of antibodies to specific fungi does not necessarily indicate a current infection; it may also indicate a simple exposure. |
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Term
| Compare and contrast dermatophytosis and pityriasis. |
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Definition
Both are noninvasive fungal infections of the epidermis. Both can be treated by topical applications of antifungals in all but the most severe cases.
Fungi called dermatophytes feed on the protein keratin, which is found in abundance in the outer layers of the skin and in hair and nails. These are all nonliving structures on the body, so the infections do not damage living tissue. The inflammatory response to the fungus may result in some generally mild damage to the tissue, which resolves when the infection is cleared.
The fungus responsible for pityriasis, Malassezia furfur, feeds on the oily secretions of the skin and generally causes no damage to the skin. Occasionally in chronic infections, the fungus interferes with the melanin production of the epidermis, producing irregular pigmentation patterns, but the damage is cosmetic. Pigmentation will return to normal some months after the fungal infection is cleared. |
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Term
| A man has difficulty breathing and 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? |
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Definition
The man may have histoplasmosis, caused by Histoplasma capsulatum, or cryptococcosis, caused by Cryptococcus neoformans. Both of these fungi are saprobes that grow in bird droppings. Inhaled spores germinate in the lungs and give rise to parasitic forms of the fungi.
H. capsulatum is a dimorphic true pathogen, and fungus from lung samples will revert to the hyphal form when grown at laboratory temperatures. Amphotericin B is the treatment of choice.
C. neoformans is a monomorphic yeast with a thick capsule. The presence of spherical yeast cells with thick capsules in tissue samples indicates infection with C. neoformans and can be confirmed by detecting C. neoformans antigens in the samples or serum. Treatment of cryptococcosis is usually a combination of amphotericin B and 5-fluorocytosine administered for several weeks. |
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Term
| Distinguish mycotoxicosis from mycetismus. |
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Definition
| Although both mycotoxicosis and mycetismus are acquired by vehicle transmission, they are ingested in different ways. Mycotoxicosis is a result of eating food that has become contaminated with fungi that have produced the toxins that are ingested. Aflatoxins are the best known mycotoxins. Mycetismus is a result of eating poisonous mushrooms. This usually occurs when a person picks and eats unidentified wild mushrooms. |
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