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MICROBIOLOGY EXAM 2 TEST
BANK|LATEST EXAM QUESTIONS
WITH ANSWERS
For the most part, all Enterobacteriaceae are positive for which biochemical
reactions?
A. Glucose, oxidase, and catalase
B. Glucose, indole, and oxidase
C. Glucose, reduce nitrates to nitrites, and oxidase
D. Glucose, catalase, and reduce nitrates to nitrites - correct-answer -D
In addition to being a group of gram-negative bacteria considered normal flora of
the gastrointestinal tract of humans and animals, which one of the following also
contains agents of important diseases such as gastroenteritis and enteric fevers,
urinary tract infections, and bacterial pneumonia?
A. Neisseriaceae
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B. Micrococcaceae
C. Enterococcus
D. Enterobacteriaceae - correct-answer -D
Most strains of Escherichia coli can be presumptively identified on the basis of
which characteristic?
A. Spot indole-positive
B. Citrate-positive
C. Methyl red-negative
D. Urease-positive - correct-answer -A
The swarming gram-negative bacillus that can be presumptively identified on the
basis of a positive indole test is:
A. Klebsiella pneumoniae.
B. Proteus vulgaris.
C. Enterobacter aerogenes.
D. Shigella sonnei. - correct-answer -B
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A gram-negative bacillus that is hydrogen sulfide (H2S)-positive, citrate-positive,
spot indole-negative, and associated with gastroenteritis in the United States is
most likely:
A. Klebsiella pneumoniae.
B. Proteus vulgaris.
C. Salmonella enteritidis.
D. Shigella sonnei. - correct-answer -C
This organism, belonging to the family Enterobacteriaceae, grows best at 25º to
30º C. Domestic and wild rats and other animals can carry this organism. What is
the medium of choice?
A. MacConkey agar
B. Xylose-lysine-deoxycholate (XLD) agar
C. Cefsulodin-irgasan-novobiocin (CIN) agar
D. Hektoen enteric (HE) agar - correct-answer -C
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Escherichia coli would appear what color on HE agar?
A. Green
B. Green with a black center
C. Yellow
D. Yellow with a black center - correct-answer -C
Enterotoxigenic and enteroinvasive are terms often linked to which of the
following bacterial species?
A. Escherichia coli
B. Salmonella enteritidis
C. Shigella sonnei
D. Yersinia pestis - correct-answer -A
A green colony with a black center is isolated on HE agar from a stool specimen. It
is most likely which organism?
A. Escherichia coli
MICROBIOLOGY EXAM 2 TEST
BANK|LATEST EXAM QUESTIONS
WITH ANSWERS
For the most part, all Enterobacteriaceae are positive for which biochemical
reactions?
A. Glucose, oxidase, and catalase
B. Glucose, indole, and oxidase
C. Glucose, reduce nitrates to nitrites, and oxidase
D. Glucose, catalase, and reduce nitrates to nitrites - correct-answer -D
In addition to being a group of gram-negative bacteria considered normal flora of
the gastrointestinal tract of humans and animals, which one of the following also
contains agents of important diseases such as gastroenteritis and enteric fevers,
urinary tract infections, and bacterial pneumonia?
A. Neisseriaceae
,2|Page
B. Micrococcaceae
C. Enterococcus
D. Enterobacteriaceae - correct-answer -D
Most strains of Escherichia coli can be presumptively identified on the basis of
which characteristic?
A. Spot indole-positive
B. Citrate-positive
C. Methyl red-negative
D. Urease-positive - correct-answer -A
The swarming gram-negative bacillus that can be presumptively identified on the
basis of a positive indole test is:
A. Klebsiella pneumoniae.
B. Proteus vulgaris.
C. Enterobacter aerogenes.
D. Shigella sonnei. - correct-answer -B
,3|Page
A gram-negative bacillus that is hydrogen sulfide (H2S)-positive, citrate-positive,
spot indole-negative, and associated with gastroenteritis in the United States is
most likely:
A. Klebsiella pneumoniae.
B. Proteus vulgaris.
C. Salmonella enteritidis.
D. Shigella sonnei. - correct-answer -C
This organism, belonging to the family Enterobacteriaceae, grows best at 25º to
30º C. Domestic and wild rats and other animals can carry this organism. What is
the medium of choice?
A. MacConkey agar
B. Xylose-lysine-deoxycholate (XLD) agar
C. Cefsulodin-irgasan-novobiocin (CIN) agar
D. Hektoen enteric (HE) agar - correct-answer -C
, 4|Page
Escherichia coli would appear what color on HE agar?
A. Green
B. Green with a black center
C. Yellow
D. Yellow with a black center - correct-answer -C
Enterotoxigenic and enteroinvasive are terms often linked to which of the
following bacterial species?
A. Escherichia coli
B. Salmonella enteritidis
C. Shigella sonnei
D. Yersinia pestis - correct-answer -A
A green colony with a black center is isolated on HE agar from a stool specimen. It
is most likely which organism?
A. Escherichia coli
