BOC Microbiology Exam Test bank 322
Questions with 100% Correct Answers
Updated 2024/2025
If present, a characteristic that is helpful in separating Pseudomonas aeruginosa form
other members of the Pseudomonas family is:
A. a positive test for cytochrome oxidase
B. oxidative metabolism in the OF test
C. production of fluorescein pigment
D. growth at 42C - Correct Answer: D
Which one of the following results is typical of Campylobacter jejuni:
A. optimal growth at 42C
B. oxidase negative
C. Catalase negative
D. nonmotile - Correct Answer: A
Optimum growth of Campylobacter jejuni is obtained on suitable media incubated at
42C in an atmosphere containing:
A. 6% O2, 10%-15% CO2, 85%-90% nitrogen
B. 10% H2, 5% CO2, 85% nitrogen
C. 10% H2, 10%CO2, 80% nitrogen
D. 25% O2, 5% CO2, 70% nitrogen - Correct Answer: A
The porphyrin test was devised to detect strains of Haemophilus capable of:
A. ampicillin degradation
B. capsule production
C. synthesis of hemin
D. chloramphenicol resistance - Correct Answer: C
Haemophilus influenzae is most likely considered normal indigenous flora in the:
A. oropharynx
B. female genital tract
C. large intestine
D. small intestine - Correct Answer: A
Haemophilus influenzae becomes resistant to ampicillin when the organism produces
a(n):
A. capsule of polysaccharide material
,B. affinity for the beta-lactam ring of the ampicillin
C. porphobilinogen
D. beta-lactamase enzyme - Correct Answer: D
An isolate on chocolate agar from a patient with epiglottitis was suggestive of
Haemphilus species. Additional testing showed that the isolate required NAD for growth
and nonhemolytic. The organism is most likely Haemophilus:
A. haemolyticus
B. ducreyi
C. influenzae
D. parainfluenzae - Correct Answer: D
Which of the following specimens is considered to be the most sensitive for the recovery
of Brucella in cases of chronic infection?
A. blood
B. urine
C. bone marrow
D. lymph node - Correct Answer: C
A genus that is found in soil and water and causes infections in immunocompromised
patients has the following characteristics:
-sheep blood agar: violet pigment
-MacConkey agar: growth
-42C incubation: growth
-oxidase: positive
-OF glucose: fermenter
-indole: negative
The genus is:
A. Campylobacter
B. Chromobacterium
C. Aeromonas
D. Serratia - Correct Answer: B
Which one of the following results is typical of Campylobacter fetus subspecies fetus?
A. optimal growth at 42C
B. oxidase negative
C. growth at 37C
D. catalase negative - Correct Answer: C
Multiple blood clutures fraom a pateint with endocarditis grew a facultatively anaerobic,
pleomorphic gram-negative bacilli with the following characteristics:
-hemolysis: negative
-MacConkey agar: no growth
-sheep blood agar: growth in 5%-10% CO2
-chocolate agar: growth in 5%-10% CO2
-catalase: negative
,-V factor: not required
-X factor: not required
-oxidase: negative
-nitrate: positive, reduced to nitrites
-indole: negative
The most likely identification is:
A. Brucella abortus
B. Actinobacillus actinomycetemcomitans
C. Haemophilus aphrophilus
D. Cardiobacterium hominis - Correct Answer: C
A gram-negative bacillus with bipolar staining was isolated from a wound infection
caused by a bite from a pet cat. The following characteristic reactions were seen:
-oxidase: positive
-glucose OF: fermentative
-catalase: positive
-motility: negative
-MacConkey agar: no growth
Which of the following is the most likely organism?
A. Pseudomonas aeruginosa
B. Pasteurella multocida
C. Aeromonas hydrophila
D. Vibrio cholerae - Correct Answer: B
A culture from an infected dog bite on a small boy's finger yielded a small, gram-
negative coccobacillus that was smooth, raised and beta-hemolytic on blood agar. The
isolate grew on MacConkey agar, forming colorless colonies. The organism was motile,
catalase positive, oxidase positive, reduced nitrate, and was urease positive within 4
hours. No carbohydrates were fermented . The most likely identification of this isolate is:
A. Brucella canis
B. Yersinia pestis
C. Francisella tularensis
D. Bordetella bronchiseptica - Correct Answer: D
While swimming in a lake near his home, a young boy cut his foot, and an infection
developed. The culture grew a nonfastidious gram-negative, oxidase positive, beta-
hemolytic, motile bacilli that produced deoxyribonuclease. The most likely identification
is:
A. Enterobacter cloacae
B. Serratia marcescens
C. Aeromonas hydrophila
D. Escherichia coli - Correct Answer: C
An aerobic, gram-negative coccobacillus was isolated on Bordet-Gengou agar from a
nasopharyngeal swab 48 hours after culture from a 6-month-old infant with suspected
pertussis. The organism exhibited the following characteristics:
, -MacConkey agar: no growth
-urea: negative at 4 hours, positive at 24 hours
-oxidase: negative
-catalase: positive
The most probable identification of this isolate is:
A. Moraxella lacunata
B. Pasteurella ureae
C. Bordetella pertussis
D. Bordetella parapertussis - Correct Answer: D
Which of the following characteristics best differentiates Bordetella bronchiseptica from
Alcoligenes species?
A. flagellar patter
B. growth at 24C
C. oxidase activity
D. rapid hydrolysis of urea - Correct Answer: D
Serum samples collected from a patient with pneumonia demostrate a rising antibody
titer to Legionella. A bronchoalveolar lavage (BAL) specimen from this patient had a
positive antigen test for Legionella but no organisms were recovered on buffered
charcoal yeast extract medium after 2 days of incubation. The best explanation is that
the:
A. antibody titer represents an earlier infection
B. positive antigen test is a false positive
C. specimen was cultured on the wrong media
D. culture was not incubated long enough - Correct Answer: D
Which characteristic best differentiates Acinetobacter species from Moraxella species?
A. production of indophenol
B. growth on MacConkey agar
C. motility
D. susceptibility to penicillin - Correct Answer: A
An organism has been identified as a member of the fluorescent group of
Pseudomonas. Which of the following sets of tests should be used to determine the
species os the organism?
A. growth at 42C, pyocyanin production, gelatinase production
B. pyocyanin production, gelatinase production, OF glucose
C. growth at 37C, pyocyanin production, OF glucose
D. gelatinase production, growth at 52C, H2S - Correct Answer: A
Appropriate culture requirements for a specimen from a patient suspected of having
tularemia include:
A. a media with cysteine such as buffered charcoal yeast extract agar
B. colistin nalidix acid agar
C. Mueller-Hinton agar with 5% sheep blood agar
Questions with 100% Correct Answers
Updated 2024/2025
If present, a characteristic that is helpful in separating Pseudomonas aeruginosa form
other members of the Pseudomonas family is:
A. a positive test for cytochrome oxidase
B. oxidative metabolism in the OF test
C. production of fluorescein pigment
D. growth at 42C - Correct Answer: D
Which one of the following results is typical of Campylobacter jejuni:
A. optimal growth at 42C
B. oxidase negative
C. Catalase negative
D. nonmotile - Correct Answer: A
Optimum growth of Campylobacter jejuni is obtained on suitable media incubated at
42C in an atmosphere containing:
A. 6% O2, 10%-15% CO2, 85%-90% nitrogen
B. 10% H2, 5% CO2, 85% nitrogen
C. 10% H2, 10%CO2, 80% nitrogen
D. 25% O2, 5% CO2, 70% nitrogen - Correct Answer: A
The porphyrin test was devised to detect strains of Haemophilus capable of:
A. ampicillin degradation
B. capsule production
C. synthesis of hemin
D. chloramphenicol resistance - Correct Answer: C
Haemophilus influenzae is most likely considered normal indigenous flora in the:
A. oropharynx
B. female genital tract
C. large intestine
D. small intestine - Correct Answer: A
Haemophilus influenzae becomes resistant to ampicillin when the organism produces
a(n):
A. capsule of polysaccharide material
,B. affinity for the beta-lactam ring of the ampicillin
C. porphobilinogen
D. beta-lactamase enzyme - Correct Answer: D
An isolate on chocolate agar from a patient with epiglottitis was suggestive of
Haemphilus species. Additional testing showed that the isolate required NAD for growth
and nonhemolytic. The organism is most likely Haemophilus:
A. haemolyticus
B. ducreyi
C. influenzae
D. parainfluenzae - Correct Answer: D
Which of the following specimens is considered to be the most sensitive for the recovery
of Brucella in cases of chronic infection?
A. blood
B. urine
C. bone marrow
D. lymph node - Correct Answer: C
A genus that is found in soil and water and causes infections in immunocompromised
patients has the following characteristics:
-sheep blood agar: violet pigment
-MacConkey agar: growth
-42C incubation: growth
-oxidase: positive
-OF glucose: fermenter
-indole: negative
The genus is:
A. Campylobacter
B. Chromobacterium
C. Aeromonas
D. Serratia - Correct Answer: B
Which one of the following results is typical of Campylobacter fetus subspecies fetus?
A. optimal growth at 42C
B. oxidase negative
C. growth at 37C
D. catalase negative - Correct Answer: C
Multiple blood clutures fraom a pateint with endocarditis grew a facultatively anaerobic,
pleomorphic gram-negative bacilli with the following characteristics:
-hemolysis: negative
-MacConkey agar: no growth
-sheep blood agar: growth in 5%-10% CO2
-chocolate agar: growth in 5%-10% CO2
-catalase: negative
,-V factor: not required
-X factor: not required
-oxidase: negative
-nitrate: positive, reduced to nitrites
-indole: negative
The most likely identification is:
A. Brucella abortus
B. Actinobacillus actinomycetemcomitans
C. Haemophilus aphrophilus
D. Cardiobacterium hominis - Correct Answer: C
A gram-negative bacillus with bipolar staining was isolated from a wound infection
caused by a bite from a pet cat. The following characteristic reactions were seen:
-oxidase: positive
-glucose OF: fermentative
-catalase: positive
-motility: negative
-MacConkey agar: no growth
Which of the following is the most likely organism?
A. Pseudomonas aeruginosa
B. Pasteurella multocida
C. Aeromonas hydrophila
D. Vibrio cholerae - Correct Answer: B
A culture from an infected dog bite on a small boy's finger yielded a small, gram-
negative coccobacillus that was smooth, raised and beta-hemolytic on blood agar. The
isolate grew on MacConkey agar, forming colorless colonies. The organism was motile,
catalase positive, oxidase positive, reduced nitrate, and was urease positive within 4
hours. No carbohydrates were fermented . The most likely identification of this isolate is:
A. Brucella canis
B. Yersinia pestis
C. Francisella tularensis
D. Bordetella bronchiseptica - Correct Answer: D
While swimming in a lake near his home, a young boy cut his foot, and an infection
developed. The culture grew a nonfastidious gram-negative, oxidase positive, beta-
hemolytic, motile bacilli that produced deoxyribonuclease. The most likely identification
is:
A. Enterobacter cloacae
B. Serratia marcescens
C. Aeromonas hydrophila
D. Escherichia coli - Correct Answer: C
An aerobic, gram-negative coccobacillus was isolated on Bordet-Gengou agar from a
nasopharyngeal swab 48 hours after culture from a 6-month-old infant with suspected
pertussis. The organism exhibited the following characteristics:
, -MacConkey agar: no growth
-urea: negative at 4 hours, positive at 24 hours
-oxidase: negative
-catalase: positive
The most probable identification of this isolate is:
A. Moraxella lacunata
B. Pasteurella ureae
C. Bordetella pertussis
D. Bordetella parapertussis - Correct Answer: D
Which of the following characteristics best differentiates Bordetella bronchiseptica from
Alcoligenes species?
A. flagellar patter
B. growth at 24C
C. oxidase activity
D. rapid hydrolysis of urea - Correct Answer: D
Serum samples collected from a patient with pneumonia demostrate a rising antibody
titer to Legionella. A bronchoalveolar lavage (BAL) specimen from this patient had a
positive antigen test for Legionella but no organisms were recovered on buffered
charcoal yeast extract medium after 2 days of incubation. The best explanation is that
the:
A. antibody titer represents an earlier infection
B. positive antigen test is a false positive
C. specimen was cultured on the wrong media
D. culture was not incubated long enough - Correct Answer: D
Which characteristic best differentiates Acinetobacter species from Moraxella species?
A. production of indophenol
B. growth on MacConkey agar
C. motility
D. susceptibility to penicillin - Correct Answer: A
An organism has been identified as a member of the fluorescent group of
Pseudomonas. Which of the following sets of tests should be used to determine the
species os the organism?
A. growth at 42C, pyocyanin production, gelatinase production
B. pyocyanin production, gelatinase production, OF glucose
C. growth at 37C, pyocyanin production, OF glucose
D. gelatinase production, growth at 52C, H2S - Correct Answer: A
Appropriate culture requirements for a specimen from a patient suspected of having
tularemia include:
A. a media with cysteine such as buffered charcoal yeast extract agar
B. colistin nalidix acid agar
C. Mueller-Hinton agar with 5% sheep blood agar
