MICROBIOLOGY EXAM 2 TEST BANK WITH APPROVED
QUESTIONS AND CORRECT ANSWERS |2026 LATEST
UPGRADED |ALREADY A+
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 - 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
B. Micrococcaceae
C. Enterococcus
D. Enterobacteriaceae - 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 - ANSWER - A
,The swarming gram-negative bacillus that can be presumptively identified on the basis of a
positive indole test is:
A. Klebsiella pneumonia.
B. Proteus vulgaris.
C. Enterobacter aero genes.
D. Sheela sonnet. - ANSWER - B
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 pneumonia.
B. Proteus vulgaris.
C. Salmonella enteritis’s.
D. Sheela sonnet. - 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 - ANSWER - C
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 - ANSWER - C
, Enter toxigenic and enter invasive are terms often linked to which of the following bacterial
species?
A. Escherichia coli
B. Salmonella enteritis’s
C. Sheela sonnet
D. Yersinia pastis - 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
B. Salmonella spp.
C. Sheela spp.
D. Klebsiella pneumonia - ANSWER - B
Escherichia coli can produce a toxin similar to Sheela dysenteries and can cause hemorrhagic
colitis. What other organ does it affect?
A. Heart
B. Lungs
C. Liver
D. Kidney - ANSWER - D
Of the following bacterial species, which is associated with a serious diarrheal illness with high
mortality rates among some populations?
A. Escherichia coli
B. Sheela spp.
C. Salmonella spp.
D. Vibrio spy - ANSWER - A
QUESTIONS AND CORRECT ANSWERS |2026 LATEST
UPGRADED |ALREADY A+
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 - 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
B. Micrococcaceae
C. Enterococcus
D. Enterobacteriaceae - 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 - ANSWER - A
,The swarming gram-negative bacillus that can be presumptively identified on the basis of a
positive indole test is:
A. Klebsiella pneumonia.
B. Proteus vulgaris.
C. Enterobacter aero genes.
D. Sheela sonnet. - ANSWER - B
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 pneumonia.
B. Proteus vulgaris.
C. Salmonella enteritis’s.
D. Sheela sonnet. - 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 - ANSWER - C
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 - ANSWER - C
, Enter toxigenic and enter invasive are terms often linked to which of the following bacterial
species?
A. Escherichia coli
B. Salmonella enteritis’s
C. Sheela sonnet
D. Yersinia pastis - 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
B. Salmonella spp.
C. Sheela spp.
D. Klebsiella pneumonia - ANSWER - B
Escherichia coli can produce a toxin similar to Sheela dysenteries and can cause hemorrhagic
colitis. What other organ does it affect?
A. Heart
B. Lungs
C. Liver
D. Kidney - ANSWER - D
Of the following bacterial species, which is associated with a serious diarrheal illness with high
mortality rates among some populations?
A. Escherichia coli
B. Sheela spp.
C. Salmonella spp.
D. Vibrio spy - ANSWER - A
