BACTE 4 Flashcards
Which of the following is (are) fluorescent stain(s) used in the detection of the mycobacteria?
a. Auramine-rhodamine
b. Kinyoun’s
c. Ziehl-Neelsen
d. Both b and c
Auramine-rhodamine
A nonpigmented mycobacterium is isolated that reduces nitrate to nitrite and is niacin-positive. You should suspect:
a. M. kansasii
b. M. xenopi
c. M. tuberculosis
d. M. avium complex
M. tuberculosis
The causative agent of Hansen disease:
a. Is highly contagious
b. Readily grows on most mycobacterial media
c. Grows best at core body temperature (37° C)
d. None of the above
None of the above
The skin test for tuberculosis
a. Detects antibodies to mycobacterial antigens
b. Detects a cell-mediated immune response to mycobacterial antigens
c. Uses the bacillus of Calmette-Guérin strain as the antigen source
d. Both a and b
Detects a cell-mediated immune response to mycobacterial antigens
Match the Shigella spp. with the corresponding group antigen: A
a. S. sonnei
b. S. boydii
c. S. dysenteriae
d. S. flexneri
. dysenteriae
Which of the following test results is most helpful in categorizing an isolate as a member of the tribe Proteeae?
a. Positive Voges-Proskauer
b. Positive urea
c. Positive phenylalanine deaminase
d. Positive lactose fermentation
Positive phenylalanine deaminase
The causative agent of plague is
a. Yersinia pestis
b. Klebsiella rhinoscleromatis
c. Citrobacter freundii
d. Serratia marcescens
Yersinia pestis
A 47-year-old patient who had just returned from Mexico was admitted to the hospital with a 3-day history of vomiting and diarrhea, without fever, and no fecal leukocytes were found in the stool. When he was admitted to the hospital, a stool culture grew an organism identified as Escherichia coli. Which of the following strains is the most likely cause of the infection?
a. EPEC
b. ETEC
c. EHEC
d. EIEC
ETEC
A gram-negative, oxidase-negative coccobacillus was isolated from the cerebrospinal fluid of an infant in the newborn nursery.
The organism produced dark pink colonies on MAC agar and had the following biochemical results: triple sugar iron, acid over acid with gas; phenylalanine deaminase-negative; sulfide-indole motility agar, H2S-negative, indole-positive, and motile; urease negative; and citrate-negative. The most probable identity of this organism is:
a. Escherichia coli
b. Enterobacter aerogenes
c. Klebsiella pneumoniae
d. Serratia marcescens
Escherichia coli
What organism is often associated with lobar pneumonia in elderly hospitalized patients?
a. Shigella spp.
b. Proteus vulgaris
c. Escherichia coli
d. Klebsiella pneumoniae
Klebsiella pneumoniae
The most common cause of community-acquired UTIs is:
a. Klebsiella pneumoniae
b. Escherichia coli
c. Providencia stuartii
d. Citrobacter freundii
Escherichia coli
Which organism is an opportunistic pathogen that causes wound and urinary tract infections and may cause the production of kidney stones?
a. Yersinia enterocolitica
b. Citrobacter freundii
c. Proteus mirabilis
d. Enterobacter cloacae
Proteus mirabilis
An enteric organism that is acquired by eating improperly prepared and cooked or preserved contaminated food and produces dysentery is:
a. P. vulgaris
b. Y. enterocolitica
c. S. marcescens
d. Shigella spp
Shigella spp
The best specimen for recovery of the mycobacteria from a sputum sample is:
A. First morning specimen
B. 10-hour evening specimen
C. 12-hour pooled specimen
D. 24-hour pooled specimen
First morning specimen
What concentration of sodium hydroxide (NaOH) is used to prepare a working decontamination solution for the processing of not normally sterile specimens for mycobacteria?
A. 1% NaOH
B. 4% NaOH
C. 8% NaOH
D. 12% NaOH
4% NaOH
strong decontamination solution (6% NaOH or greater) may kill or severely damage the mycobacteria. Overtreatment may result in fewer positive cultures.
Which is the most appropriate nonselective medium for recovery of mycobacteria from a heavily contaminated specimen?
A. Lowenstein–Jensen agar
B. Middlebrook 7H10 agar
C. Petragnani’s agar
D. American Thoracic Society medium
Petragnani’s agar
All four media contain malachite green as an
inhibitory agent of nonmycobacteria,but Petragnani’s medium contains a higher concentration
Mycobacteria stained by the Ziehl–Neelsen or Kinyoun methods with methylene blue counterstain are seen microscopically as
A. Bright red rods against a blue background
B. Bright yellow rods against a yellow background
C. Orange-red rods against a black background
D. Bright blue rods against a pink background
Bright red rods against a blue background
Acid-fast staining of a smear prepared from digested sputum showed slender, slightly curved, beaded, red mycobacterial rods. Growth on Middlebrook 7H10 slants produced buff-colored microcolonies with a serpentine pattern after 14 days at 37°C. Niacin and nitrate reduction tests were positive. What is the most probable presumptive identification?
A. Mycobacterium tuberculosis
B. Mycobacterium ulcerans
C. Mycobacterium kansasii
D. Mycobacterium avium–intracellulare complex
Mycobacterium tuberculosis
Which organism, associated with tuberculosis in cattle, causes tuberculosis in humans, especially in regions where dairy farming is prevalent?
A. Mycobacterium avium–intracellulare complex
B. Mycobacterium kansasii
C. Mycobacterium marinum
D. Mycobacterium bovis
Mycobacterium bovis
M. bovis is also called the bovine tubercle bacillus. A nonvirulent strain, bacillus Calmette–Guerin (BCG), is used as a tuberculosis vaccine throughout the world
Which of the following organisms are used as controls for rapid growers and slow growers?
A. Mycobacterium fortuitum and Mycobacterium tuberculosis
B. Mycobacterium avium-intracellulare complex and Mycobacterium tuberculosis
C. Mycobacterium chelonei and Mycobacterium fortuitum
D. Mycobacterium kansasii and Mycobacterium tuberculosis
Mycobacterium fortuitum and Mycobacterium tuberculosis
Which of the following Mycobacterium spp. produce(s) pigmented colonies in the dark (is a scotochromogen)?
A. M. szulgai
B. M. kansasii
C. M. tuberculosis
D. All of these options
M. szulgai
All of the following mycobacteria are associated with skin infections except:
A. Mycobacterium marinum
B. Mycobacterium haemophilum
C. Mycobacterium ulcerans
D. Mycobacterium kansasii
Mycobacterium kansasii
Biochemically, the Enterobacteriaceae are gram-negative rods that:
A. Ferment glucose, reduce nitrate to nitrite, and are oxidase negative
B. Ferment glucose, produce indophenol oxidase,and form gas
C. Ferment lactose and reduce nitrite to nitrogen gas
D. Ferment lactose and produce indophenol oxidase
Ferment glucose, reduce nitrate to nitrite, and are oxidase negative
The ortho-nitrophenyl-β-galactopyranoside (ONPG) test is most useful when differentiating:
A. Salmonella spp. from Pseudomonas spp.
B. Shigella spp. from some strains of Escherichia coli
C. Klebsiella spp. from Enterobacter spp.
D. Proteus vulgaris from Salmonella spp
Shigella spp. from some strains of Escherichia coli
The Voges–Proskauer (VP) test detects which end product of glucose fermentation?
A. Acetoin
B. Nitrite
C. Acetic acid
D. Hydrogen sulfide
Acetoin
At which pH does the methyl red (MR) test become positive?
A. 7.0
B. 6.5
C. 6.0
D. 4.5
4.5
A positive Simmons citrate test is seen as a:
A. Blue color in the medium after 24 hours of incubation at 35°C
B. Red color in the medium after 18 hours of incubation at 35°C
C. Yellow color in the medium after 24 hours of incubation at 35°C
D. Green color in the medium after 18 hours of incubation at 35°C
Blue color in the medium after 24 hours of incubation at 35°C
In the test for urease production, ammonia reacts to form which product?
A. Ammonium citrate
B. Ammonium carbonate
C. Ammonium oxalate
D. Ammonium nitrate
Ammonium carbonate
Which of the following reagents is added to detect the production of indole?
A. p-Dimethylaminobenzaldehyde
B. Bromcresol purple
C. Methyl red
D. Cytochrome oxidase
p-Dimethylaminobenzaldehyde
Decarboxylation of the amino acids lysine, ornithine, and arginine results in the formation of:
A. Ammonia
B. Urea
C. CO2
D. Amines
Amines
