Part V: Mycology
Regarding the structure and reproduction of fungi, which one of the following is most accurate?
(A) Peptidoglycan is an important component of the cell wall of fungi.
(B) Molds are fungi that grow as single cells and reproduce by budding.
(C) Some fungi are dimorphic (i.e., they are yeasts at room temperature and molds at body temperature).
(D) The fungal cell membrane contains ergosterol, whereas the human cell membrane contains cholesterol.
(E) As most fungi are anaerobic, they should be cultured under anaerobic conditions in the clinical laboratory.
Regarding fungal pathogenesis, which one of the following is most accurate?
(A) Ingestion of Amanita mushrooms typically causes kidney failure.
(B) The host response to infection by the systemic fungi, such as Histoplasma and Coccidioides, consists of granulomas formation.
(C) The fever seen in systemic fungal infections is caused by endotoxin-induced release of interlukin-1.
(D) Ingestion of aflatoxin produced by Aspergillus flavus can cause adenocarcinoma of the colon.
(E) A positive result in the skin test to fungal antigens, such as coccidioidin, is caused by an immediate hypersensitivity reaction.
Regarding the mode of action of antifungal drugs, which one of the following is most accurate?
(A) Azole drugs, such as fluconazole, act by inhibiting ergosterol synthesis.
(B) Amphotericin B acts by inhibiting fungal protein syntheses at the 40S ribosomal subunit.
(C) Terbinafine acts by inhibiting fungal DNA synthesis but has no effect on DNA synthesis in human cells.
(D) Echinocandins, such as caspofungin, act by inhibiting messenger RNA synthesis in yeasts but not in molds.
The selective toxicity of amphotericin B is based on the presence in fungi of which one of the following?
(A) 30S ribosomal subunit
(B) Dihydrofolate reductase
Regarding ringworm and the dermatophytes, which one of the following is most accurate?
(A) The dermatophytes are molds and are not thermally dimorphic.