drmagrann.comdrmagrann.com/MLT/Unit 2 flashcards, 36-58.docx · Web viewIndividuals considered at greatest risk for contracting brucellosis are: dairy farmers. Facultative, intracellular

Micro Flashcards Unit 2

1) Individuals considered at greatest risk for contracting brucellosis are:

dairy farmers.

2) Facultative, intracellular parasitic bacteria are those that are able to:

exist in both intracellular and extracellular environments

3) Organisms belonging to the genus Brucella are:

gram-negative coccobacilli

4) Although in vitro susceptibility testing is not reliable, which regimen of antibiotics is recommended for Brucella infections?

Doxycycline and rifampin

5) The animal reservoir for Brucella melitensis is:

sheep or goats

6) Pertussis (whooping cough) is an epidemic disease that is a highly contagious, acute infection of the upper respiratory tract caused by the

Bordetella spp

7) The mode of transmission of Bordetella pertussis can best be described as

person-to-person contact

8) During the catarrhal stage of pertussis, symptoms are

runny nose and mild cough

9) During the paroxysmal stage of pertussis, symptoms are

severe and violent coughing

10) Acceptable specimens for the detection of Bordetella pertussis are

nasopharyngeal aspirates

11) Because of its longer shelf life, the medium of choice to cultivate Bordetella spp. is

Regan-Lowe agar

12) Which of the following toxins contributes to the virulence of Bordetella pertussis and works by hemolyzing red cells and activating cyclic adenosine monophosphate, which inactivates several types of host immune cells?

Adenylate cyclase toxin

13) Bordetella pertussis colonies growing on Regan-Lowe medium yields which of the following colonial morphologic appearances?

Mercury-drop colonies

14) A nasopharyngeal aspirate is cultured on Bordet-Gengou agar, and growth is observed. The colonies are also subjected to a direct fluorescent antibody (DFA) stain, which is also positive. On the basis of these findings, the antimicrobial therapy that should be administered to the patient is

Azithromycin

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15) If real-time polymerase chain reaction (PCR) is performed on a Bordetella isolate, then it must be noted that this type of swab is unacceptable for collection because of the presence of which of the following inhibitory factors?

Calcium alginate

16) Organisms belonging to the genus Neisseria are:

gram-negative diplococci

17) The JEMBEC transport system for Neisseria spp. provides an atmosphere with increased _________ to keep the organism viable during transport

carbon dioxide (CO2)

18) An endocervical swab was collected from a 26-year-old woman with a purulent discharge. The Gram stain revealed the following:

• Many white blood cells (WBCs)• Moderate gram-negative diplococci• Moderate gram-negative coccobacilli• Few yeastBased on these findings, what would be the next course of action?

Report the Gram stain, and follow up with culture

19) Gram-negative diplococci are isolated from a genital specimen and yield the following results:

• Glucose: positive• Maltose: negative• Lactose: negativeThe organism can be identified as:

Neisseria gonorrhoeae

20) The bacterial species that can be described as oxidase-positive, glucose-positive, maltose-positive, sucrose-negative, lactose-negative, and a major cause of bacterial meningitis is:

Neisseria meningitidis

21) An organism isolated from a sputum sample that has a “hockey puck” consistency would have what biochemical profile?

Glucose-negative, maltose-negative, and lactose-negative

22) Which two organisms should be used to determine the validity of the nitrate reduction test?

N. lactamica and M. catarrhalis

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23) A gram-negative diplococcus grew on 5% sheep blood agar and chocolate agar, had scant growth on MacConkey agar, and had no growth on modified Thayer-Martin (MTM) agar. The organism was identified as N. sicca. What explains the discrepancy of the results obtained on the MTM agar?

No discrepancy is present. N. sicca does not grow on MTM agar.

24) The differentiation of the similar Moraxella catarrhalis and Neisseria can be best accomplished by:

glucose utilization testing

25) MTM, Martin-Lewis (ML), and New York City (NYC) media were all developed for the selective isolation of which organism?

N. gonorrhoeae

26) Gonococci require which of the following nutrients for growth:Arginine, Hypoxanthine, Uracil or IsoVitaleX?

IsoVitaleX

27) Moraxella catarrhalis may be described as: oxidase-positive28) The gram-negative coccus that can be

described as oxidase-positive, glucose-negative, maltose-negative, sucrose-negative, lactose-negative, and DNase-positive is:

Moraxella catarrhalis

29) Moraxella catarrhalis can be described as a: gram-negative diplococcus30) Moraxella catarrhalis may be differentiated

from gonococci and meningococci on the basis of its:

production of DNase

31) The determination of carbohydrate utilization patterns for the differentiation of Neisseria spp. and M. catarrhalis is best performed by:

heavy inoculation of buffered, low-peptone substrate with dextrose, maltose, lactose, and sucrose.

32) Which statement is true regarding the pathogenesis of Neisseria cinerea?

A. N. cinerea is a leading cause of fatal bacterial meningitis.

B. Virulence factors include pili, capsule formation, and endotoxin.

C. Disseminated intravascular coagulation (DIC) and thrombocytopenia are complications of infection.

D. N. cinerea is commonly encountered as a contaminant in clinical specimens.

D. N. cinerea is commonly encountered as a contaminant in clinical specimens.

33) Blood cultures collected for the recovery of Neisseria gonorrhoeae or N. meningitidis require:

less than 0.025% SPS

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34) An advantage of all molecular assays is: The ability to test for Chlamydia trachomatisfrom the same specimen at the same time

35) Which one of the following statements is true regarding antimicrobial therapy and susceptibility testing?

A. Cephalosporins and macrolides are ineffective against Moraxella catarrhalis.

B. Resistance to quinolones is emerging in strains of Neisseria gonorrhoeae.

C. Most Neisseria spp. are resistant to penicillin.

D. Most strains of N. meningitidis are resistant to penicillin.

B. Resistance to quinolones is emerging in strains of Neisseria gonorrhoeae.

36) An acceptable specimen for anaerobic culture is:

Tissue obtained at biopsy

37) During specimen collection, an important thing to remember when handling a collection device with an oxygen-free atmosphere is to:

Take care not to tip the container

38) The indicator used to determine whether anaerobic conditions are achieved in an anaerobic jar is:

Methylene blue

39) Prereduced, anaerobically sterilized (PRAS) media:

Are produced, packaged, shipped, and stored under anaerobic conditions

40) Actinomyces spp., Bifidobacterium spp., and Clostridium spp. can be described as:

Microaerophilic organisms that can grow in the presence of either reduced or atmospheric oxygen but grow best under anaerobic conditions

41) Tissue biopsy taken from a puncture wound is:

Acceptable

42) Aspiration of peritoneal fluid using a needle and syringe is:

Acceptable

43) Feces in a sterile specimen cup is: Not acceptable44) Bronchial washing collected with a double

lumen–plugged catheter is:Acceptable

45) Expectorated sputum is: Not acceptable46) Cervical swab is: Not acceptable47) Rectal swab is: Not acceptable48) Urine via percutaneous aspiration is: Acceptable49) Nasopharyngeal swab is: Not acceptable50) Urine via catheter is: Not acceptable51) Percutaneous lung aspirate is: Acceptable52) The final fill of the anaerobe jar prepared by

the evacuation-replacement method consists of:

80% to 90% nitrogen, 5% to 10% hydrogen, and 5% to 10% CO2

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53) To isolate anaerobic gram-positive organisms, which of the following media should be used?

Anaerobic phenylethyl alcohol agar (PEA)

54) An anaerobic media, which contains ferric ammonium citrate and hemin, bile salts, and gentamicin, is used to isolate which group of organisms?

Bacteroides spp.

55) What media isolates Prevotella and Bacteroides spp?

LKV blood agar

56) What media inhibits gram-negative rods? PEA agar57) What media is non selective; supports the

growth of facultative anaerobes and aerobes?Thioglycollate broth

58) What media determines lecithinase and lipase production of Clostridia and Fusobacteria?

Egg-yolk agar

59) What media is selective for Clostridium difficile?

CCFA

60) Characteristics that strongly indicate the presence of pigmented Prevotella or Porphyromonas in a clinical specimen include

brick-red fluorescence under long-wavelength ultraviolet (UV) light

61) In a clinical specimen, sulfur granules strongly indicate the presence of which anaerobe?

Actinomyces

62) A diabetic patient has developed gas gangrene of the right foot. The most likely anaerobe causing this infection is

C. perfringens

63) Optimal recovery and identification of anaerobic bacteria in clinical specimens occurs when:

the initial incubation period is at 35° to 37° C for 48 hours

64) The ethanol shock or heat shock test will separate which two bacteria?

Clostridium and Bifidobacterium

65) The most likely identification of a bile-sensitive, kanamycin-resistant, catalase-negative, and indole-negative anaerobic gram-negative bacilli is

nonpigmented Prevotella

66) The most likely identification of a bile-resistant, kanamycin-resistant, colistin-resistant, and vancomycin-resistant anaerobic gram-negative bacilli is

Bacteroides fragilis group

67) The most likely identification of an anaerobic gram-negative bacilli that will fluoresce brick red or has a brown-to-black-pigment is

Porphyromonas

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68) The most likely identification of an anaerobic gram-negative bacillus that reduces nitrate and requires formate and fumarate for growth in broth culture is

Bacteroides ureolyticus

69) The most likely identification of kanamycin-sensitive and anaerobic gram-negative bacilli that fluoresce a chartreuse color is

Fusobacterium

70) The primary plating medium used to select out Clostridia spp. would be

phenylethyl alcohol agar (PEA)

71) Fecal cultures to isolate Clostridium difficile are plated on

cycloserine cefoxitin fructose agar (CCFA).

72) Quality control is set up on a new lot of an indole reagent. Clostridium bifermentans and Clostridium bolteae are used, and the following results are obtained: • C. bifermentans: positive • C. bolteae: negative

No discrepancy is present. The results obtained are correct

73) Incubation conditions for anaerobic cultures include

incubation for 48 hours before exposing the culture to air

74) The most likely identification of an anaerobic gram-positive bacillus that is a very large fusiform bacillus with one pointed end and one blunt end is:

Leptotrichia

75) The most likely identification of an anaerobic gram-negative coccus is

Veillonella

76) The most likely identification of an anaerobic gram-positive coccus that is resistant to metronidazole is:

Streptococcus

77) The most likely identification of an anaerobic, curved, gram-variable bacillus with tapered ends on Gram stain of vaginal secretions when vaginosis is suggested is:

Mobiluncus

78) The most likely identification of an anaerobic gram-positive bacillus that produces spores is

Clostridium

79) Are kanamycin-resistant, colistin-resistant, and vancomycin-resistant and grow in 20% bile

Bacteroides fragilis group

80) Fluoresce brick red or have a brown-to-black pigment

Pigmented Prevotella

81) Characteristics that are found in the bacteria called Mycobacterium are:

a cell wall that contains N-glycolylmuramic acid and has a high lipid content.

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82) The term complex as used in theM. tuberculosis complex:

is used to describe two or more species whose distinction is complicated and of little or no medical importance

83) Examples of the mycobacterial species that occur in humans and belong to the Mycobacterium tuberculosis complex include:

M. tuberculosis, M. bovis, M. bovis BCG, and M. africanum.

84) The recent emergence of epidemic multidrug-resistant strains of Mycobacterium tuberculosis, in conjunction with the end of the downward trend of reported cases of tuberculosis in the United States, has been largely attributed to:

human immunodeficiency virus (HIV) epidemic.

85) The tuberculin skin test, or the purified protein derivative (PPD) test, is based on:

delayed hypersensitivity cell-mediated immunity to certain antigenic components of the organism.

86) A positive tuberculin skin test, or PPD test, is characterized by:

erythema and induration.

87) The Runyon system of classification is based on:

growth rate and colonial pigmentation.

88) Slow-growing NTM whose colonies become pigmented when exposed to light are referred to as:

photochromogens.

89) Slow-growing NTM whose colonies are pigmented when grown in the dark or the light are referred to as:

scotochromogens.

90) Slow-growing NTM whose colonies produce no pigment, whether they are grown in the dark or the light, are referred to as:

nonphotochromogens.

91) The most commonly isolated mycobacterium in the United States is:

M. avium-intracellulare

92) Known to cause an inflammatory bowel disease referred to as Johne disease in cattle, sheep, and goats, which organism has been isolated from the bowel mucosa of patients with Crohn disease?

M. paratuberculosis

93) Mycobacterium fortuitum, M. chelonae, and M. abscessus are:

responsible for approximately 90% of clinical mycobacterial disease.

94) Which of the following species of Mycobacterium causes a chronic disease of the skin, mucous membranes, and nerve tissue but has not yet been cultivated in vitro?

M. leprae

95) The primary reservoir of the Mycobacterium responsible for leprosy is:

infected humans.

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96) The specimen of choice for detecting tuberculous pulmonary mycobacterial disease is:

spontaneously produced sputum.

97) The specimens of choice for detecting nontuberculous mycobacterial disease are:

bronchial lavages, washings, and brushings.

98) The specimens of choice for detecting urinary tract mycobacterial disease are:

three daily clean-catch midstream urine samples

99) What quantity of cerebrospinal fluid (CSF) is considered sufficient for the detection of tuberculous meningitis?

10 mL

100) The specimen of choice for detecting mycobacterium in a skin lesion or wound is a:

needle aspiration

101) Specimens for Mycobacterium studies that require concentration, decontamination, or liquefaction include:

sputum.

102) Sodium hydroxide (NaOH), Zephiran–trisodium phosphate, N-acetyl-L-cysteine–NaOH (NALC-NaOH), and oxalic acid are associated with:

digestion and decontamination of specimens for mycobacterial studies

103) The type of specimen collected for mycobacterial studies that must be neutralized with 10% sodium carbonate is:

gastric lavage

104) On Gram stain, mycobacteria appear as: poorly stained, beaded, gram-positive bacilli

105) The nonpathogenic Mycobacterium commonly found in tap water, which has been a problem when tap water or deionized water has been used in the preparation of smears, is:

M. gordonae

106) The fluorochrome method of staining Mycobacterium:

enables the smear to be initially examined at lower magnifications.

107) One drawback associated with the fluorochrome stain method for detecting Mycobacterium is that:

many rapid growers may not appear fluorescent with these reagents

108) The stain that requires heating the slide for better penetration of stain into the mycobacterial cell wall is known as the:

Ziehl-Neelsen

109) The stain that does not require heating the slide for better penetration of stain into the mycobacterial cell wall is known as the:

Kinyoun

110) Acid-fast smears should be examined carefully by scanning at least ________ oil immersion field.

300

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111) Fluorescent staining is more sensitive than conventional carbolfuchsin stains. What counterstain is used during the procedure?

Potassium permanganate

112) Optimal conditions for most mycobacterial cultures are:

35° C in the dark in an atmosphere of 5% to 10% CO2 and high humidity.

113) Optimal conditions for the recovery of M. haemophilum from specimens include:

placement of an X-factor disk on the media.

114) Negative mycobacterial cultures are reported final and the cultures are discarded after what period?

8 weeks

115) The first test that is always performed on organisms growing on solid or liquid mycobacterial media is a(n):

acid-fast stain

116) Quality control is performed to test the validity of catalase production at 68° C. M. fortuitum and M. tuberculosis are used, which yield a positive and negative reaction, respectively. Which one of the following statements explains this discrepancy?

No discrepancy is present. M. fortuitum is catalase-positive and M. tuberculosis is catalase-negative at 68° C.

117) When culturing for Mycobacterium, rapid growers usually produce colonies within how many days after subculture?

3 to 4 days

118) Under what circumstance might slow-growing mycobacteria appear to produce colonies in a few days?

When the inoculum is too heavy

119) For reliable results, the niacin test should be performed only from cultures that are at least:

3 weeks old and show at least 50 colonies on Löwenstein-Jensen medium

120) In the identification of mycobacterial isolates, the niacin test involves the:

accumulation of niacin in the medium in which the organism is growing

121) In the identification of mycobacterial isolates, the catalase test involves the:

measurement of the height of a column of bubbles of oxygen.

122) In the identification of mycobacterial isolates, the Tween 80 test involves:

a lipase that is able to hydrolyze polyoxyethylene sorbitan monooleate into oleic acid and polyoxyethylated sorbitol.

123) The 3-day test that is useful for identifying the rapid growers, M. fortuitum and M. chelonae, and that measures the rate by which this enzyme breaks down phenolphthalein disulfate into phenolphthalein and other salts is the ____________ test.

arylsulfatase.

124) Which continuous growth system uses a CO2 sensor to monitor mycobacterial growth?

BacT/Alert

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125) A fisherman who cut himself on a fishing hook later develops a cutaneous disease at the inoculation site. The exudate is aspirated and set up on a routine AFB medium for culture. It is incubated at 37° C, but no growth is observed after 8 weeks; however, a slide of the exudate was AFB-positive. Which one of the following statements explains these findings?

The organism should have been incubated at 30° C

126) Long, slender, helically curved, gram-negative bacilli with tight coils are identified as belonging to which species

Treponema

127) Long, slender, helically curved, gram-negative bacilli with hooked ends are identified as belonging to which species

Leptospira

128) Systemic symptoms, such as fever, weight loss, malaise, and a loss of appetite, along with a widespread rash, can be observed in patients suffering from _________ syphilis.

secondary

129) A widely used nontreponemal serologic assay is the ________ test.

rapid plasma reagin (RPR)

130) The most common vector-borne disease in North America and Europe transmitted by the bite of Ixodes ticks is caused by:

Borrelia burgdorferi

131) A destructive lesion of the gums, also known as acute necrotizing ulcerative gingivitis, that is caused by oral spirochetes and other bacteria is known as

Vincent’s disease

132) A stage of venereal syphilis characterized by the appearance of a chancre is known as __________ syphilis

primary

133) A stage of venereal syphilis, characterized by tissue destruction, central nervous system disease, cardiovascular abnormalities, eye disease, and granuloma-like lesions, is known as ________ syphilis

tertiary

134) Treponemal antibodies are those that are produced against antigens of the organisms themselves

135) Nontreponemal antibodies are those that are:

produced by infected patients against components of mammalian cells

136) A nontreponemal flocculation serologic test in which soluble antigen particles are coalesced to form larger particles that are visible as clumps when they are aggregated by antibody is called the __________ test

VDRL

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137) A specific treponemal serologic test performed by overlaying whole treponemes that are fixed to a slide with serum from patients suspected of having syphilis and using fluorescein-conjugated antihuman antibody reagent to detect specific antitreponemal antibodies is called the _________ test

FTA-ABS

138) A test that uses gelatin particles sensitized with T. pallidum subsp. pallidum antigens to detect specific antitreponemal antibodies in patient serum is called the __________ test.

TP-PA

139) A self-limiting illness and the most common clinical syndrome associated with leptospirae that includes fever, headache, myalgia, and aseptic meningitis in the immune stage is called

anicteric leptospirosis

140) The most severe illness associated with leptospirae, with symptoms of liver, kidney, and/or vascular dysfunction with lethal pulmonary hemorrhage and sometimes death, is called

icteric leptospirosis

141) The Centers for Disease Control and Prevention (CDC) recommendations for testing in suspected cases of Lyme disease are to screen with ______ and confirm with ________.

IFA; immunoblotting

142) A patient has a reactive RPR result and a positive FTA-ABS test. The drug of choice to treat this infection is:

penicillin G

143) An automated system uses bead-capture technology in the detection of which of the following spirochetes?

Treponema

144) The Jarisch-Herxheimer reaction is associated with the clearance of organism from the bloodstream and the release of cytokines within hours of antibiotic treatment. With which spirochete is this condition associated?

Borrelia

145) This protozoa has a trophozoite stage but no cyst stage and reproduces via longitudinal binary fission. The parasite belongs to which category?

Flagellates

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146) Babesia spp. is transmitted via the bite of a tick and can cause severe disease in patients who have been splenectomised or who are immunocompromised. To diagnose accurately these patient populations, the specimen of choice is:

Blood

147) Wuchereria, Brugia, Loa, and Onchocerca are all classified as:

filarial nematodes.

148) A bone marrow aspirate is examined for the presence of parasites from a patient who has been traveling in Latin America for several months and who came in contact with a triatomid bug. Which parasite will most likely be identified?

Trypanosoma cruzi

149) The eggs of which of the following intestinal parasites are not commonly found in feces and must be detected by other diagnostic techniques?

Enterobius vermicularis

150) Which of the following intestinal parasites is found in humans and also in pigs?

Balantidium coli

151) Some strains of leishmaniae have reservoir hosts, including dogs and wild rodents. Transmission is via the bite of a:

Sandfly

152) A 17-year-old male with a severe eye infection admits that he does not clean his contact lenses as often as he should. His eye infection is most likely the result of which parasite?

Acanthamoeba spp.

153) A 7-year-old girl was at summer camp and dove into the lake many times. She complained that water went up her nose a few times. Several days later she is unresponsive and comatose and rushed to the hospital. A cerebrospinal fluid (CSF) specimen is drawn, and several motile amebae are observed. She is most likely suffering from an infection with which of the following parasites?

Naegleria fowleri

154) The specimen of choice to collect in suspected cases of Paragonimus infection is: sputum

155) Which of the following is currently the only fixative available that does not contain formalin, polyvinyl alcohol (PVA), or mercury?

TOTAL-FIX

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156) The concentration protocol of the ova and parasite (O&P) examination:

is designed to allow the detection of protozoan cysts, coccidian oocysts, microsporidial spores, and helminth eggs and larvae

157) The permanent stained smear protocol of the O&P examination:

is designed to facilitate the identification of intestinal protozoa.

158) A 4-year-old boy who is in day care 3 days per week is irritable and scratching the area around his anus. What morphologic characteristics would most likely be observed on microscopic examination of the appropriate specimen?

Football-shaped eggs with one flattened side

159) The Entero-Test capsule technique involves the collection of duodenal contents to examine the presence of which of the following parasites?

Giardia lamblia

160) A urine sample from a 26-year-old woman is examined, and an organism is observed that displays “jerky” motility. This organism is classified as a(n):

flagellate.

161) A modified acid-fast stain is performed on lung tissue. The most likely organism that will be observed is:

Cryptosporidium spp.

162) A medical laboratory scientist (MLS) is examining a thin blood film from a patient suspected of having a Plasmodium infection. After examining the slide for 5 minutes and viewing approximately 100 oil immersion fields, the MLS does not observe any structures associated with Plasmodium. Which one of the following statements explains this discrepancy?

The MLS may have missed the organism; more than 300 files should be viewed.

163) The PARA-TECT Cryptosporidium/Giardia test kit uses which of the following formats for detection?

Direct fluorescent antibody (DFA)

164) The parasite Toxoplasma gondii is acquired via the ingestion of infected oocysts from cat feces. A diagnosis is primarily made through:

serologic means.

165) The peripheral chromatin, which contains fine granules that are uniform in size and are evenly distributed, can be found in which protozoa?

Entamoeba histolytica

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166) The presence of which cells is diagnostic for the intestinal protozoan, Entamoeba histolytica, which measures 15 to 20 microns?

Red blood cells (RBCs)

167) A patient has amebic colitis. A microscopic examination reveals the following: • 18 microns in diameter • Fine granules • Centrally located karyosome • Cytoplasm with a “ground glass” appearance • RBC inclusionsThis protozoan can be identified as:


168) A tissue sample is sent to the laboratory and microscopically examined for the presence of amebae. To differentiate between the host cells and the organism, _______ stain is used to allow the organisms to appear bright pink with a green-blue background.

periodic acid-Schiff (PAS)

169) A patient is diagnosed with a severe intestinal disease caused by Entamoeba histolytica. Which treatments should be administered?

Metronidazole plus iodoquinol

170) Entamoeba coli, a protozoan that ranges from 15 to 25 microns in diameter, can contain up to eight nuclei in mature cysts. How would the karyosome expect to appear on a stained slide?

Large, not compact

171) An intestinal protozoan appeared 8 microns in diameter with a small, compact, centrally located karyosome. Four nuclei were observed in the mature cyst. The organism can be identified as:

E. hartmanni

172) Which nonpathogenic protozoa has a very large glycogen vacuole in its cyst form and measures approximately 5 to 20 microns in diameter?

Iodamoeba butschlii

173) The drug of choice for the parasite Blastocystis hominis, which is believed to produce proteases and is considered a virulence factor responsible for its pathogenesis, is:

Metronidazole

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174) Which intestinal protozoa has no cyst stage, ranges from 9 to 12 microns in diameter, and has two nuclei in 60% of clinical specimens?

Dientamoeba fragilis

175) This flagellate is pear-shaped with “falling leaf” motility. It contains variant-specific surface proteins (VSPs) on its surface, which provide a mechanism for the organism to survive in the small intestine as a result of its ability to resist intestinal proteases. The organism is:

Giardia lamblia

176) Which flagellate has a single nucleus in the cyst and the typical curved, cytostomal fibril, which is called ashepherd’s crook?

Chilomastix mesnili

177) The cyst form of Balantidium coli is the infective stage. It has one large kidney-shaped macronucleus and one small, round micronucleus. The troph is quite large, measuring 50 to 150 microns in length and 40 to 70 microns in width. What single feature is associated with this organism?

Cilia covering the troph

178) Asexual amplification, called merogony, is associated with the life cycle of which organism?

Cryptosporidium

179) Highly active antiretroviral therapy (HAART) is the most effective prophylaxis and treatment in patients with acquired immunodeficiency syndrome (AIDS) with which type of infection?

Cryptosporidium

180) Outbreaks of infection with the organism Cyclospora are linked to contaminated raspberries, lettuce, and snow peas. The stain of choice to identify the oocysts in stool samples is:

modified acid-fast

181) The Isospora belli organism, which contains two sporocysts with four sporozoites each, is recovered from fecal specimens and has also been implicated in traveler’s diarrhea. The drug of choice to treat infection caused by I. belli is:

trimethoprim-sulfamethoxazole combination

182) The organism Sarcocystis has an obligatory two-host life cycle—an intermediate host and definitive host. The sporocysts found in a stool specimen, which measure 9 to 16 microns, are broadly oval with slightly ___________ ends.

tapered

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183) When cooking meat, an internal temperature of ____° C must be reached to kill organisms such as Toxoplasma and Sarcocystis.

68

184) The polar tubule, which is responsible for the entrance of infective sporoplasm into the host cell, is found in which genera?

Enterocytozoon

185) In cases of malaria, the primary exoerythrocytic cycle occurs in the?

liver

186) Delicate ring forms and crescent-shaped gametocytes are the only forms normally observed in the peripheral blood of which Plasmodium spp.?

P. falciparum

187) A thick ring, large nucleus, and bands across the cell and 6 to 12 merozoites in a mature schizont are all characteristics of which Plasmodium spp.?

P. malariae

188) Cerebral malaria is considered to be the most serious complication and major cause of death with which species of Plasmodium spp.?

P. falciparum

189) Plasmodium vivax is suspected in a patient who has been traveling for months in the tropics. Blood was collected in a lavender top tube; however, the slide was not prepared for examination until the next day because the specimen came in on the night shift. Once the slide was prepared and examined, Schüffner dots were not visible. Which one of the following statements explains this discrepancy?

The blood remained in the tube too long, yielding false-negative results.

190) Resistance to chloroquine and mefloquine has been identified in which Plasmodium spp.?

P. falciparum

191) Ring forms and a “Maltese cross” were observed in a blood smear. The vector that transmits this disease is a(n)?

tick.

192) Chagas disease is caused by? T. cruzi.193) The vector Glossina palpalis group

transmits the Trypanosoma brucei gambiense organism. The diagnostic stage is the?

trypomastigote.

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194) Stage I of trypanosomiasis characteristically involves systemic trypanosomiasis infection without central nervous system (CNS) involvement. Lymphadenopathy is also a feature of this disease. The trypomastigotes of which protozoa are involved?

T. brucei gambiense

195) In Trypanosoma brucei rhodesiense trypanosomiasis infections, CNS invasion occurs early. The disease progresses rapidly, and death may occur before extensive CNS involvement. Inflammation of which organ is more common and severe with this disease form?

Heart

196) Humans contract Chagas disease when the reduviid bug defecates while taking a blood meal and the parasites in the feces are rubbed or scratched into the bite wound or onto mucosal surfaces. Which stage in the blood infects the host cells?

Trypomastigote

197) The most frequent clinical signs of chronic Chagas disease involve the enlargement of which organ?

Heart

200) Match the size and shape of the parasitized RBCs as they appear in Giemsa-stained thin blood smears.A. Normal shape and sizeB. Normal shape; size may be normal or

slightly smallerC. 1.5 to 2.0 times larger than normal; oval to

normalD. 60% of cells are larger than normal and oval

1. Plasmodium vivax2. P. ovale3. P. falciparum4. P. malariae5. P. knowlesi

1. Plasmodium vivax2. P. ovale3. P. falciparum4. P. malariaeA. = 5 P. knowlesiB. = 4 P. malariaeC. = 1 Plasmodium vivaxD. = 2 P. ovale

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201) Match the vector with the organism it infects.

A. Anopheles mosquitoB. Tsetse flyC. SandflyD. Reduviid bug

1. Trypanosoma cruzi2. T. brucei rhodesiense3. T. brucei gambiense4. T. rangeli

A. NoneB. T. brucei gambienseC. NoneD. T. rangeli

202) A 15-year-old male was diving in a lake when he inhaled some of the stagnate water. Five days later he was admitted to the hospital, comatose and in critical condition. A cerebrospinal fluid (CSF) specimen was taken, and several motile amoebae were observed. The patient would most likely be diagnosed with which of the following conditions?

Primary amebic meningoencephalitis

203) The CSF would reveal which of the following results in infections caused by N. fowleri?

Decreased glucose, increased protein, and negative Gram stain

204) The Acanthamoeba organism is motile and has spinelike pseudopods, a single round nucleus in the cyst form, and a large karyosome in the nucleus of the troph. An estimated 70% of clinical cases of Acanthamoeba keratitis are misdiagnosed as __________ keratitis.

viral

205) Tissues suspected of containing Acanthamoeba cysts can be observed using various stains. A cyst that stains black has most likely been stained with the __________ stain.

methenamine silver

206) Primates, as well as dogs, sheep, and horses, have died of central nervous system (CNS) infections with which organism?

Balamuthia mandrillaris

207) Trichomoniasis is the primary nonviral sexually transmitted disease worldwide. One complication of this infection is:

endometritis.

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208) A 26-year-old woman has an odorous vaginal discharge, lower abdominal pain, and difficulty urinating. Vaginal secretions are collected and sent to the laboratory for examination 3 hours after collection. No motile organisms are observed on the wet preparation; however, Trichomonas vaginalis is suspected. Which one of the following statements explains this discrepancy?

No discrepancy is present; this organism in nonmotile

209) The troph of the motile Trichomonas vaginalis organism measures 7 to 23 microns long and 5 to 15 microns wide. The recommended treatment of choice for this urogenital infection is:

metronidazole

210) Laboratory diagnosis of Trichomonas gondii is confirmed by:

serologic testing.

211) Tachyzoites (Toxoplasma gondii) appear as?

Crescent-shaped

212) Bradyzoites (Toxoplasma gondii) appear as?

Tissue cysts

213) Sporozoites (Toxoplasma gondii) appear as?

Oocysts from cat feces

214) The most common and largest roundworm encountered is:

Ascaris lumbricoides

215) The eggs of the Ascaris lumbricoides worm are ingested and hatched in the duodenum, penetrate the intestinal wall, and migrate to the hepatic portal circulation. Its geographic distribution and infection rate are associated with:

poor sanitation

216) Löffler syndrome is associated with which roundworm infection?

Ascaris lumbricoides

217) A 4-year-old boy attended day care 3 days per week. He was irritable, and his parents noticed that he had persistent perianal itching. A sticky paddle was pressed against the perianal region and sent to the laboratory for testing. The eggs microscopically observed would most likely have which one of the following morphologic features?

Flat-sided, football-shaped

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218) The infective larvae of the parasite Strongyloides stercoralis penetrate the skin and migrate through the circulatory system to the heart and lungs. The organism enters the bronchial tree and is then swallowed, entering the digestive tract, where the organism matures into an adult worm. This parasite is classified as which type of infection?

Threadworm

219) A short buccal capsule, large bulb on the esophagus, and prominent genital primordium are all characteristics of which worm?

Strongyloides stercoralis

220) The larvae of the worm Strongyloides stercoralis are the most common found in human stool specimens. Depending on the fecal transit time through the intestine and the patient’s condition, both rhabditiform and rare filariform may be present. The treatment of choice for uncomplicated infections is:

ivermectin

221) A 36-year-old man entered the emergency department with bleeding and weight loss several weeks after returning from a trip to South America. A stool sample was taken and microscopically examined. Barrel-shaped eggs with bipolar plugs were observed. The organism can be identified as:

Trichuris trichiura

222) Direct penetration of which of the following worms results in tissue damage at the site of attachment, blood loss, and an acute gastrointestinal phase demonstrated by an increased eosinophilia?

Hookworm

223) Rhabditiform larvae measuring 275 μmicrons with a long buccal capsule and a small genital primordium was identified as hookworm. Which one of the following statements explains this discrepancy?

No error occurred. Hookworm is the correct identification for an organism with these characteristics

224) Humans acquire infection with Trichinella tissue nematode by ingesting undercooked meat that contains the infective encysted larvae. In which tissue do these larvae encyst?

Striated muscle

225) A definitive diagnosis can be made in a Trichinella infection on the basis of which of the following findings?

Identification of encysted larvae through muscle biopsy

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226) A child is believed to have a Toxocara cati infection in his eye, which he acquired after playing with a stray cat for several weeks. A serum titer was performed, which revealed a titer of 1:8. This laboratory value can be interpreted as:

diagnostic

227) Systemic involvement is rare in infection caused by Ancylostoma braziliense or A. caninum; however, pneumonitis may occur. The antihelminthic therapy used to treat this infection is

ivermectin or thiabendazole

228) What is the mode of transmission for Dracunculus medinensis?

Copepods

229) What is the mode of transmission for Parastrongylus cantonensis?

Crabs

230) What is the mode of transmission for Trichinella spp.?

Pigs

231) What is the mode of transmission for Parastrongylus costaricensis?

Snails

232) The definitive host and reservoir for Wuchereria bancrofti is:

Humans

233) Chyluria is a result of lymphatic rupture and fluid entering the urine. Another lymphatic condition caused by Wuchereria bancrofti is:

Elephantiasis.

234) A 36-year-old man who has been traveling through the orient is experiencing a tender region in the inguinal region. A blood film is made, and sheathed microfilariae with four to five subterminal nuclei and two terminal nuclei in the tail are identified using Giemsa stain. The organism is most likely:

Brugia malayi

235) A skin snip is performed, and microfilariae with tapered tails, no nuclei, and unsheathed are microscopically observed. The recommended therapy for this infection is:

Ivermectin.

236) A Giemsa stain is performed on an eye exudate on a patient with calabar swelling, eosinophilia, and a recent travel history to Africa. Loa loa is suspected; however, the sheath in the adult worm recovered does not stain. Which one of the following statements explains this discrepancy?

No discrepancy is present. The sheath does not stain with Giemsa stain.

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237) Which organism is transmitted by Tabanid fly?

Loa loa

238) Which organism is transmitted by Biting midges?

Mansonella spp

239) Which organism is transmitted by Anopheles mosquito?

Brugia spp.

240) Which organism is transmitted by Black fly? Onchocerca241) The Diphyllobothrium latum tapeworm

can reach up to 10 meters in length and can have more than 3000 to 4000 proglottids. The definitive host and reservoir host, respectively, are:

humans and fish.

242) The double-pored tapeworm, Diphyllobothrium caninum, consisting of many small proglottids, measures 10 to 70 cm in length as an adult. The scolex contains four suckers and an armed rostellum. The intermediate host in which infective cysticercoids develop is the:

flea.

243) The mode of infection for which of the following organisms is the ingestion of cysticercoid in an infected arthropod or by the direct ingestion of the egg? Autoinfection may also occur.

Hymenolepis nana

244) The Taenia solium organism, which causes cysticercosis and can grow to be 1.5 to 8 meters long, contains 7 to 13 lateral uterine branches along the proglottid. The intermediate host is:

pigs.

245) A stool specimen is examined, and a tapeworm with the following characteristics are observed:

• 15 to 18 lateral branches on each side • Scolex with four suckers • No hookletsThe intermediate hosts of this tapeworm are:

cattle.

246) Epileptic seizures, headaches, and mental disturbances all result from infection with the Taenia solium organism. The definitive diagnosis is based on

identification of cysts in tissue

247) Hydatid disease is associated with which tapeworm?

Echinococcus granulosus

248) In Echinococcus granulosus infections, the hydatid cysts usually occur in which organ?

Liver

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249) Fur trappers and veterinarians are at an increased risk for this infection by being exposed to infected animals. The intermediate hosts of the organism, Echinococcus multilocularis, are:

Rodents

250) The Taenia multiceps tapeworm is 5 to 6 cm long and consists of 200 to 250 segments. It has four suckers in its scolex and a proboscis with 22 to 32 hooks arranged in two rows. This organism causes which condition?

Coenurosis

251) The intermediate host of the Platyhelminthes is freshwater

snails

252) The life-cycle stages of the intestinal trematodes after the eggs are shed from the body via feces is best described as

miracidium larva, redia, cercariae, and metacercariae

253) The adult form of the fluke, Fasciolopsis buski, is elongated in shape and ranges from 20 to 75 mm long and 8 to 20 mm wide with an oral sucker at the anterior and a ventral sucker approximately midway to the posterior. The reservoir host for the fluke is

dogs

254) The Heterophyes heterophyes worm, which has a genital sucker that surrounds the genital pore, has a variety of reservoir hosts including dogs, cats, and birds and a second intermediate host of freshwater:

Fish

255) A 36-year-old man who has traveled for several weeks in the orient is experiencing abdominal pain and diarrhea with a large amount of mucus. A Heterophyes heterophyes egg measuring 28 by 15 microns is identified in the stool. The treatment of choice for this intestinal trematode is:

Praziquantel

256) Which second intermediate host ingests the cercariae of Clonorchis and Opisthorchis?

Freshwater fish

257) The adult worm of Fasciola measures 2 to 5 cm by 0.8 to 1.3 cm with a cephalic cone at the anterior end that contains the oral sucker. The drug of choice to treat Fasciola infections is:

bithionol.

258) Charcot-Leyden crystals are often observed in specimens infected with which one of the following trematodes?

Paragonimus westermani

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259) The eggs of Paragonimus mexicanus measure approximately 80 microns by 40 microns, are unembryonated and operculated, and have thick shells that are brownish yellow. An individual with this infection has most likely traveled to which endemic area?

South America

260) Match the fluke classification with the corresponding organismOpisthorchis viverrini Southeast Asian liver flukeFasciola spp. Sheep liver flukeClonorchis (Opisthorchis) sinensis Chinese liver flukeParagonimus westermani Lung fluke

261) The only intermediate host required in the life cycle of blood flukes is a:

freshwater snail.

262) The eggs of the blood fluke Schistosoma haematobium range from 110 to 170 microns long by 40 to 70 microns wide and have a sharp, pointed terminal spine. In which specimen is this organism most likely found?

Urine

263) A large lateral spine is characteristic of which Schistosoma egg?

S. mansoni

264) Rodents, marsupials, and nonhuman primates are all reservoirs for hich Schistosoma species?

S. intercalatum

265) An egg of the organism of Schistosoma mansoni is isolated from the feces of an adult man who has been traveling in Africa. An unoperculated egg with a large lateral spine is recovered. The patient is administered the standard dose of praziquantel; however, his infection does not improve. Which one of the following statements explains this discrepancy?

A larger dose may be required to be effective against this organism

266) Which of the following organisms causes visceral Larval migrans?

Toxocara canis

267) Enterobius vermicularis infection is usually diagnosed by finding eggs from

Cellulose tape preps

268) The infective stage for Strongyloides stercoralis is

Filariform larvae

269) If humans ingest the egg of Taenia solium, they may develop

Cystercercosis

270) A silver methenamine stained slide of a bronchial washing from an AIDs patient is examined. Which of the following parasites

Pneumocystis carinii

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is most likely to be identified?271) A blood smear showed crescent shaped

gametocytes in several red cells. What is the most probable identity of the organisms?

Plasmodium falciparum

272) Which organism is transmitted to humans by ticks and blood transfusions?

Babesia

273) The ameba which can cause liver or lung abscesses is


274) Which of the following can cause a fatal maningoencephalitis?

Naegleria fowleri

275) The trophozoite of which organism is characterized by “falling leaf motility”, two nuclei, an axostyle, 4 pair of flagella and a sucker on the underside of the organism?

Giardia lamblia

276) Which of the following eggs may not be detected in zinc flotation procedures?

Schistosoma mansoni

202) Which trophozoite is suspected if ingested red cells are seen on saline wet prep? Entamoeba histolytica

203) Pregnant women are to avoid cleaning litter boxes of their house cats until after delivery to prevent congenital infection of?

Toxoplasma gondii.

204) A patient visiting from overseas is hospitalized due to suspected tuberculosis. The sputum sample submitted to the laboratory is bloody with orange-brown flecks. Preliminary TB tests are negative. Which parasite may be suspected?

Paragonimus westermani

205) Which of the following cysts has a prominent karyosome with a clear karyolymph space (no achromatic granules). The nuclei no peripheral chromatin?

Endolimax nana

206) Differential diagnosis of Cryptosporidium parvum and Cyclospora cayetanesis cayetanesis is based on:

Oöcyst size – Cyclospora is larger.

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drmagrann.comdrmagrann.com/MLT/Unit 2 flashcards, 36-58.docx · Web viewIndividuals considered at greatest risk for contracting brucellosis are: dairy farmers. Facultative, intracellular