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أسئلة Mycology

1. Regarding ringworm and the dermatophytes, which one of the following is most
accurate?
(A) The dermatophytes are molds and are not thermally dimorphic.
(B) The drug of choice for the treatment of ringworm lesions is amphotericin B.
(C) The purpose of the KOH prep is to observe fungal antigens within infected
cells.
(D) The dermatophytid reaction refers to the necrotic area typically seen in the
center of ringworm lesions.
(E) The principal reservoir of dermatophytes in the genus Trichophyton is
domestic animals such as dogs and cats.

1. Regarding C. albicans, which one of the following is most accurate?
(A) The diagnosis of disseminated candidiasis is typically made by detecting IgM
antibodies.
(B) It exists as a yeast on mucosal surfaces but forms pseudohyphae when it
invades tissue.
(C) Antibody-mediated immunity is a more important host defense than cellmediated immunity.
(D) A positive skin test can be used to confirm the diagnosis of skin infection
caused by C. albicans.
(E) In the clinical laboratory, it is diagnosed by isolating a mold with nonseptate
hyphae when cultures are grown at room temperature.

2. Regarding Cryptococcus neoformans, which one of the following is most
accurate?
(A) It is a dimorphic fungus, growing as a mold in the soil and a yeast in the
body.
(B) It is acquired primarily by ingestion of food contaminated with pigeon guano.
(C) Dark field microscopy is typically used to visualize the organism in spinal
fluid.
(D) Pathogenesis involves an exotoxin that acts as a superantigen recruiting
lymphocytes into the spinal fluid.
(E) Laboratory diagnosis of cryptococcal meningitis can be achieved by detecting
the capsular polysaccharide of the organism in the spinal fluid.

3. Regarding Aspergillus fumigatus and aspergillosis, which one of the following is
most accurate?
(A) The natural habitat of A. fumigatus is the hair follicles of the human skin.
(B) In the clinical laboratory, cultures of A. fumigatus incubated at 37°C form
yeast colonies.
(C) The India ink stain is typically used to visualize A. fumigatus in the clinical
laboratory.
(D) A. fumigatus causes “fungus balls” in patients with lung cavities caused by
tuberculosis.
(E) The main predisposing factor to allergic bronchopulmonary aspergillosis is
neutropenia

4. Regarding Mucor species, which one of the following is most accurate?
(A) Infection is acquired by the ingestion of food contaminated by spores of the
organism.
(B) Diabetic ketoacidosis is a major predisposing factor for invasive
mucormycosis.
(C) Mucor species have septate hyphae in contrast to Aspergillus species, which
have nonseptate hyphae.
(D) In biopsy specimens obtained from patients with invasive disease, Mucor
species appear as pseudohyphae.
(E) Skin tests using mucoroidin as the immunogen are used to determine whether
the patient has been infected with Mucor species.

5. Your patient is a 20-year-old woman who is human immunodeficiency virus
(HIV) antibody positive with a CD4 count of 50. She has recovered from
cryptococcal meningitis. Which one of the following is the best choice of drug to
use as long-term prophylaxis to prevent another episode of cryptococcal
meningitis?
(A) Amphotericin B
(B) Caspofungin
(C) Fluconazole
(D) Flucytosine
(E)Terbinafine

6. Your patient is a 1-month-old infant with whitish lesions in the mouth that are
diagnosed as oropharyngeal candidiasis (thrush). Which one of the following is
the best choice of drug to treat this infection?
(A) Amphotericin B
(B) Caspofungin
C) Fluconazole
(D) Flucytosine
(E) Terbinafine

7. Your patient is a 50-year-old woman with leukemia who is neutropenic from her
cancer chemotherapy. She now has disseminated aspergillosis that does not
respond to amphotericin B. Which one of the following is the best choice of drug
to treat this infection?
(A) Amphotericin B
(B) Caspofungin
(C) Fluconazole
(D) Flucytosine
(E) Terbinafine

ANSWERS
1. (B)
2. (E)
3. (D)
4. (B)
5. (C)
6. (C)
7. (B)

28) Dimorphism in fungi refers to:
a-the ability of fungi to produce two types of spores
b-the ability of fungi to undergo mitosis as well as meiosis
c-the property of fungi to develop spherical and elongated forms of nuclei
d-the characteristic of certain fungi to develop male and female hyphae in one colony
E-the ability of fungi to grow in two different forms, yeast and mycelial, depending on environmental conditions