Mycology


(Courtesy of Dr. William Kaplan; Public Health Image Library, Centers for Disease Control and Prevention; Atlanta, Georgia.)


a. Aspergillosis


b. Candidiasis


c. Histoplasmosis


d. Mucormycosis


336. A 65-year-old man was diagnosed with pseudomembranous candidiasis and given a prescription for oral fluconazole. This drug acts by:


a. Binding to membrane ergosterol


b. Incorporation into RNA leading to mistranslation and inhibits DNA synthesis


c. Inhibition of 1,3-β-glucan biosynthesis


d. Inhibition of mitosis


e. Inhibition of squalene 2,3-epoxidase


f. Inhibition P450-dependent sterol demethylase (lanosterol 14α-demethylase)


337. An AIDS patient with a CD4 count in the range 100 to 50 cells/mm3 complains of headache and neck stiffness and appears disoriented. The possibility of fungal meningitis is considered and tests for the common fungal etiology of meningitis ordered. Tests included direct examination of spinal fluid for the organism and serology. The purpose of the serology test is detection of


a. Antibody to capsular polysaccharide


b. Antibody to cell wall mannoprotein


c. Capsular polysaccharide


d. Cell wall mannoprotein


338. A 6-year-old African American girl resident of a very large US city presents to a clinic with scaly patches and areas of alopecia on the scalp with hair shafts broken off close to the scalp. The hair did not fluoresce under Wood’s light. If this child has tinea capitis, the most likely etiology is


a. Epidermophyton floccosum


b. Microsporum audouinii


c. Microsporum canis


d. Trichophyton rubrum


e. Trichophyton tonsurans


339. A 25-year-old male physical therapist trains regularly with the hope of qualifying for the Boston Marathon. He develops itching in interdigital spaces on his left foot. Suspecting tinea pedis he treats the area with an over-the-counter product. The area improves after a course of treatment but two months later reappears and again responded to the same treatment. However, there was reappearance 3 months later. If the self-diagnosis is correct, the normal habitat of the etiologic agent is most likely described as


a. Anthropophilic


b. Geophilic


c. Zoophilic


340. A patient receiving corticosteroid treatment for lupus developed headache and fever and when she began to display some memory loss she was brought to her physician by her spouse. Considered in the differential diagnosis was cryptococcal meningitis. Which of the following, if found upon examination of cerebrospinal fluid would support that diagnosis?


a. Encapsulated yeast cells


b. Hyphae


c. Intracellular yeast cells


d. Yeast cells with multiple buds


e. Yeast cells with a broad base between mother and daughter cells


341. A 35-year-old male, a legal resident in the USA, presented with a complaint of a lesion on the bottom of his foot that was smooth and shiny and somewhat discolored. He reported that it bothered him when wearing some shoes. He reported no chronic diseases or recent illnesses and he was a nonsmoker. Travel history determined that he frequently visited relatives in India. Histopathology of the biopsy specimen showed at 2.4-mm granule surrounded by neutrophils. Tissue staining suggested that the granule contained filaments >1 μm in width. The most likely diagnosis is


a. Actinomycetoma


b. Aspergillosis


c. Chromomycosis


d. Eumycetoma


e. Phaeohyphomycosis


342. A healthy 55-year-old man resident of Louisville, Kentucky, presented to his physician complaining of fever, headache, nonproductive cough, and chest pain of 10 days duration. As part of the history, the patient reported that he was still employed as a construction worker and for several weeks prior to becoming ill had been engaged in tearing down houses and structures as part of an urban renewal project. The most likely fungal infection considered in the differential diagnosis is


a. Blastomycosis


b. Coccidioidomycosis


c. Cryptococcosis


d. Histoplasmosis


e. Paracoccidioidomycosis


f. Sporotrichosis


343. A 40-year-old woman sees her primary care physician complaining of an ulcer on her finger. She reported that it started as a red bump. Knowing that her patient was a long-time avid gardener, the physician asked if that finger had been injured by a thorn. The patient responded that she did not remember about that particular finger but she certainly had received thorn punctures in past weeks. Based on this information, which of the following is the most likely fungal etiology?


a. Fonsecaea pedrosoi


b. Malassezia furfur


c. Microsporum canis


d. Sporothrix schenckii


e. Stachybotrys chartarum


344. Several young men from the local high school football team complain of a sudden onset of athlete’s foot (tinea pedis). Which of the following observations in a skin scraping will support the diagnosis?


a. Hyaline hyphae and arthroconidia


b. Pigmented hyphae


c. Sclerotic bodies


d. Spherules


e. Yeast cells


345. A 57-year-old obese, white female with type 1 diabetes mellitus is diagnosed with strep throat and prescribed penicillin. A week later she returns complaining of a sore mouth and white patches on the tongue. Your examination confirms the white pseudomembranous lesions. Material from the lesion is obtained and prepared for microscopic examination. Your suspicion of the most likely clinical diagnosis will be confirmed by observation of buccal epithelial cells, leukocytes, and which of the following


a. Gram-positive bacteria


b. Gram-negative bacteria


c. Hyphae with septa and acute angle branching


d. Spherules containing endospores


e. Yeast cells, hyphae, and pseudohyphae


346. A small brownish irregular macule on the palm of a 13-year-old girl is examined by a dermatologist in her Louisiana home town. A skin scraping from the lesion is obtained for microscopic observation and culture. Microscopic examination of the specimen shows brownish filaments or hyphae and yeast cells. The most likely diagnosis is


a. Tinea capitis


b. Tinea corporis


c. Tinea manuum


d. Tinea nigra


e. Tinea pedis


347. You have been designated as a coordinator of construction of a bone marrow transplant unit (BMTU). There will be extensive removal of walls and floors in order to install the laminar flow rooms required for a BMTU. From the standpoint of frequency and lethality, which of the following fungi should be your biggest concern?


a. Aspergillus species


b. Candida species


c. Cryptococcus species


d. Penicillium species


e. Pneumocystis jiroveci


348. A 50-year-old man, newly employed by a commercial farm that supplies eggs and chickens to industry, develops a flu-like syndrome with fever, chills, myalgia, headache, and a nonproductive cough. He is diagnosed with histoplasmosis. A positive tissue biopsy would show the presence of


a. Arthrospores


b. Oval budding yeast cells inside macrophages


c. Spherules containing endospores


d. Tuberculate macroconidia


e. Yeast cells, hyphae, and pseudohyphae


f. Yeast cells with broad-based bud


349. A 65-year-old female patient with a long history of diabetes is brought the emergency room by her daughter with an immediate complaint of sudden swelling on the right side of the face and bleeding from the right nostril. Questioning of the patient and daughter suggests the possibility of ketoacidosis. The nasal bleeding is troublesome and a swab of the nares is rushed to the clinical laboratory for immediate attention along with blood to test for acidosis. The patient was admitted. The facial lesion became partially necrotic and there was slight protrusion of the right eye and facial paralysis. The patient died on the second day. If this patient died of a fungal infection, histopathologic examination of the lesions would most likely show…


a. Hyphae, some with arthroconidia


b. Septate dematiaceous hyphae


c. Septate hyphae with acute angle branching


d. Nonseptate hyphae


e. Narrow (<1 μm) Gram-positive filaments


f. Yeast cells


350. A normally healthy young man in Arizona was diagnosed with coccidioidomycosis. The most likely route of infection for the etiologic agent is


a. Aspiration


b. Cutaneous contact


c. Ingestion


d. Inhalation


e. Implantation


351. An immunocompromised patient is suspected of having aspergillosis due to A. fumigatus. Which of the following clinical conditions is most likely to occur?


a. Allergic bronchopulmonary response


b. Aspergilloma


c. Invasive pulmonary infection


d. Otomycosis


e. Wound infection


352. A 25-year-old pregnant woman, living in the San Joaquin Valley (California), experiences an influenza-like illness with fever and cough. She is diagnosed with Coccidioides infection. The most likely recommended treatment for the infection of this patient is


a. Amphotericin B or fluconazole


b. 5-fluorocytosine


c. None, the infection resolves without treatment


d. Supportive treatment only for symptoms


e. Terbinafine


353. Months after a kidney transplant, a 45-year-old woman who was receiving immunosuppressive therapy experienced a rapid onset of respiratory insufficiency and a dry cough. High-resolution computed tomographic scanning was ordered of the lungs. There were findings of interstitial disease. Bronchoalveolar lavage was performed and the material examined by Giemsa staining. The report stated that trophic forms and cysts were observed. The most likely infecting organism is


a. Aspergillus fumigatus


b. Candida albicans


c. Pneumocystis jiroveci


d. Rhizopus arrhizus (oryzae)


354. Bacteria and fungi share some common mechanisms of resistance to drugs used in treatment of bacterial or fungal infection. However, bacteria have a resistance mechanism not described in fungi. This mechanism is


a. Alteration in the drug target


b. Efflux of drug


c. Inactivation of drug


d. Influx of drug


e. Overexpression of drug target


355. An isolate of Candida albicans was found to be resistant to caspofungin due to mutation in the drug target which is


a. Cytosine permease


b. Ergosterol


c. P450 14-α-demethylase


d. Squalene 2,3-epoxidase


e. Subunit of β-1,3-glucan synthase


356. A 25-year-old man made a self-diagnosis of athlete’s foot and purchased a product advertised to treat this condition that listed the active ingredient as tolnaftate. The mode of action of this drug is


a. Binding to membrane ergosterol


b. Incorporation into RNA leading to mistranslation and inhibition DNA synthesis


c. Inhibition of 1,3-β-glucan biosynthesis


d. Inhibition of mitosis


e. Inhibition of squalene 2,3-epoxidase


f. Inhibition P450-dependent sterol demethylase (lanosterol 14α-demethylase)


357. A 37-year-old HIV-positive male presented with fever, cough, facial papules, and pustules. Microscopic examination of a stained smear of material obtained from a pustule showed structures that could be described as those stained red or dark in the periodic acid Schiff stained tissue specimen below. These pustular lesions are most likely attributable to infection with


Image


(Courtesy of Dr. Libero Ajello; Public Health Image Library, Centers for Disease Control and Prevention; Atlanta, Georgia.)


a. Blastomyces dermatitidis


b. Candida albicans


c. Cryptococcus spp.


d. Histoplasma capsulatum


e. Penicillium marneffei


358. An 18-year-old white male high-school student visits the family physician complaining of a diffuse, painful rash extending from his midthigh to his navel region. In recounting the history of the rash, he indicates that one of his football teammates gave him topical hydrocortisone to treat a minor groin rash. A KOH scraping of the lesion reveals hyaline hyphae and a portion of the scraping is submitted for culture. A schematic of the microscopic observation of the culture is shown below. The most likely etiology is


Image


(Reproduced, with permission, from Brooks GF et al. Jawetz’s Medical Microbiology. 22nd ed. New York: McGraw-Hill; 2001:536.)


a. Epidermophyton floccosum


b. Microsporum canis


c. Trichophyton rubrum


d. Trichophyton tonsurans


359. A 37-year-old male presented with a lesion on the left leg. He reported receiving abrasions in the area 3 or 4 months earlier while on tour in Brazil. The lesion was a pink, smooth papular lesion, which he reported itched. The lesion was biopsied and the clinical pathology laboratory reported the presence of short, brownish hyphal fragments and sclerotic or Medlar bodies. The most likely diagnosis for this patient is


a. Blastomycosis


b. Chromoblastomycosis


c. Lacaziosis


d. Eumycetoma


e. Sporotrichosis


360. An 87-year-old man complained that his feet hurt when he put on shoes because of his toenails. Upon inspection several toenails on both feet showed yellowing and thickening. A scraping was obtained from one nail as well as subungual debris and prepared for culture and direct examination with potassium hydroxide and Calcofluor. Microscopic examination showed fluorescent hyphae. The most likely diagnosis is


a. Tinea capitis


b. Tinea corporis


c. Tinea manuum


d. Tinea pedis


e. Tinea unguium


361. A 55-year-old man from Mississippi presented with a lesion below his left eye. Examination showed a well-demarcated lesion with a raised border, scaling, and pustules. He reported no pain. Material from the edge of the lesion was submitted for histopathology and culture. The pathology laboratory reported the presence of broad-based budding yeast cells. The diagnosis for this patient is


a. Blastomycosis


b. Chromomycosis


c. Paracoccidioidomycosis


d. Penicilliosis


e. Sporotrichosis


362. A 47-year-old man from Cincinnati, Ohio, suspected to have community-acquired pneumonia was treated with antibiotics. When he failed to improve, histoplasmosis was considered. Among the tests ordered were serology, direct examination, and culture of induced sputum. In culture, the microscopic morphology most useful in identification of the etiologic agent is


a. Arthroconidia


b. Microconidia


c. Sclerotic bodies


d. Spherules


e. Tuberculate macroconidia


363. A 25-year-old female had surgery for a crush injury to the chest. She had a central venous catheter, was intubated, and was on a mechanical ventilator. Three days postsurgery she developed a fever and was treated empirically for bacterial infection but fever persisted. Fungemia was suspected and blood culture for fungi was ordered. Empiric antifungal therapy was initiated and the central venous catheter line was removed. Removal of the catheter is indicated because


a. Of the suspected presence of Aspergillus fumigatus biofilm


b. Of the suspected presence of Candida albicans biofilm


c. Of the suspected presence of Cryptococcus neoformans biofilm


d. Of the suspected presence of Aspergillus fumigatus planktonic organisms


e. Of the suspected presence of Candida albicans planktonic organisms


f. Of the suspected presence of Cryptococcus neoformans planktonic organisms


364. A 75-year-old African American male who had recently retired to the Tucson, Arizona area from Ohio, presented with history of cough, fever, and chills for 3 weeks. Because of the recent move and ethnicity, the patient was tested for coccidioidomycosis. This infection is initiated following inhalation of structures best described as


a. Arthroconidia


b. Blastoconidia


c. Endospores


d. Spherules


e. Sporangiospores


365. A 4-year-child develops tinea corporis (ringworm). The lesions clear using a preparation for treatment of athlete’s foot obtained from local drug store. The lesions reappear on the child and a playmate in a few weeks. Internet research suggested to the mother that the family pet might be the source of infection and should be taken to a veterinarian. If this is the mode of transmission, the etiology is most likely


a. Epidermophyton floccosum


b. Hortaea werneckii


c. Malassezia spp.


d. Microsporum canis


e. Trichosporon beigelii


366. A patient from a small Mississippi town presented with a complaint of several weeks of productive cough, hemoptysis, weight loss, and chest pain. Radiologic findings were consistent with a pulmonary infiltrate. Among the possible diagnoses, blastomycosis was considered and culture for this organism was included in the orders for the clinical laboratory. The structure distinctive for identification in microscopic examination of a culture of the etiologic agent is


a. Arthroconidia


b. Broad-based budding yeast cells


c. Encapsulated yeast cells


d. Multiply budding yeast cells


e. Tuberculate macroconidia


367. Candida albicans is isolated in blood culture from a patient in a surgical intensive care unit. This most likely source of the infecting organism is


a. A health care worker


b. A visitor


c. Ambient air


d. The patient


e. The surgeon


368. A 30-year-old female of the US military was on assignment in a subtropical area. She reported to the physician with a complaint of patchy light-colored lesions on her chest and upper arms. She reported no other symptoms. Upon examination the lesions were irregular and well demarcated. Included in the differential diagnosis was pityriasis versicolor. A scraping on an affected area was obtained. If the diagnosis of pityriasis versicolor is correct, the best description of what will be observed in a positive specimen is


a. Hyaline hyphae


b. Hyaline hyphae and arthroconidia


c. Dematiaceous hyphae


d. Yeast cells with broad-based buds


e. Yeast cells and short hyphae


369. A 56-year-old man retired from the military to his hometown in Wisconsin. While in the military he had been stationed in several states and served in several parts of the world including South America, Africa, Southeast Asia, and most recently in Iraq and Afghanistan. He complained to his physician of a lesion inside his mouth on the left side. Histopathology of a biopsy specimen stained with methenamine silver was similar to that shown below. The most likely diagnosis is


Image


(Courtesy of the Public Health Image Library, Centers for Disease Control and Prevention; Atlanta, Georgia.)


a. Blastomycosis


b. Candidiasis


c. Histoplasmosis


d. Leishmaniasis


e. Paracoccidioidomycosis


370. The overexpression of drug efflux pumps in Candida albicans is an important mechanism in reduced susceptibility to


a. Azole class drugs


b. Echinocandin class drugs


c. Flucytosine


d. Polyene class drugs


371. A 28-year-old woman experienced vaginal and vulvar itching, a slightly watery discharge and pain with intercourse. Her gynecologist performed physical examination of the vulva, vagina, and cervix. The vaginal pH was estimated as 4.4. Microscopic examination was performed on some Gram-stained discharge material. The observation was similar to below. The most likely diagnosis is


Image


(Courtesy of Dr. Stuart Brow; Public Health Image Library, Centers for Disease Control and Prevention; Atlanta, Georgia.)


a. Bacterial vaginosis


b. Candidiasis


c. Chlamydial vaginitis


d. Trichomoniasis


e. Viral vaginitis


372. A 53-year-old white woman with end-stage renal disease received a kidney transplant and was maintained on an immunosuppressive regimen. Three months later she had a fever (38.3°C) and was found to have acute renal failure. Renal transplant biopsy was performed. Periodic acid-Schiff staining of a biopsy section showed yeast cells and hyphae. The most likely diagnosis for this patient is infection with


a. Aspergillus fumigatus


b. Candida albicans


c. Candida glabrata


d. Cryptococcus neoformans


e. Rhizopus arrhizus (oryzae)


373. Amphotericin B is noted for both its antifungal efficacy and side effects when administered to humans. The basis for the side effects is most likely


a. Binding of drug to cholesterol


b. Binding of drug to ergosterol


c. Binding of drug to phospholipids


d. Inhibition of cholesterol biosynthesis


e. Inhibition of ergosterol biosynthesis


374. A fungal teleomorph is


a. Asexual reproductive form


b. Infective form for humans


c. Sexually reproductive form


d. Dormant form




Answers


335. The answer is a. (Brooks, pp 646-647. Levinson, pp 351-352. Murray, Ch 73. Ryan, pp 723-733, 743-746.) Aspergillus is widespread in nature and produces small conidia that are easily aerosolized. Atopic individuals often develop severe allergic reactions to the conidial antigens. In immunocompromised patients, the conidia may germinate to produce hyphae that invade the lungs and other tissues. Progress of disease can be rapid. A diagnosis of aspergillosis is supported by a tissue biopsy showing invasion by the organism and a positive culture from a normally sterile site. Aspergilli may be airborne in the environment and be laboratory culture contaminants or present in orally obtained samples from patients without apparent clinical illness and at low risk for invasive aspergillosis and such finding should be interpreted with caution. In tissue Aspergillus

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