BOC Microbiology Actual Exam Questions
with 100% Correct Answers 2025 Latest
Update
An aerobic, gram negative coccobacillus was isolated on Bordet-Gengou agar from a
nasopharangeal swab 48 hours after culture from a 6mo infant with suspected
pertussis. The organism exhibited the following characteristics:
MAC: no growth
urea: negative at 4hrs, pos at 24 hrs
oxidase: -
catalase: +
the most probably ID of this isolate is:
a. Moraxella lacunata
b. Pasteurella ureae
c. Bordetella pertussis
d. Boretella parapertussis - Answer-d. Boretella parapertussis
-B pertussis is oxidase pos, urea neg
Which of the following characteristics best differentiates Bordetella bronchiseptica from
Alcaligenes species?
a. flagellar pattern
b. growth at 24'C
c. oxidase activity
d. rapid hydrolysis of urea - Answer-d. rapid hydrolysis of urea
-Bronchiseptica is urea pos within 4 hours
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 nalidixic acid agar
c. Mueller-Hinton agar with 5% sheep blood agar
d. Regan-Lowe media - Answer-a. a media with cysteine such as buffered charcoal
yeast extract agar
-Francisella requires cysteine
A child was butten on the arm by her sibling and the resulting wound grew a slender
gram-negative bacilli that has the following characteristics:
growth on SBA: colonies that "pit" the agar
colonies odor: like bleach
catalase: -
,oxidase: +
TSI: no growth
The ID of this organism is:
a. Moraxella catarrhalis
b. Eikenella corrodens
c. Kingella kingae
d. Legionella pneumophila - Answer-b. Eikenella corrodens
Characteristics of the genus Capnocytophagia include:
a. grows in ambient air
b. colonies are large and spreading after 2-4 days
c. considered "nonfermenter"
d. gram positive bacillus - Answer-b. colonies are large and spreading after 2-4 days
Differentiating tests that will separate Burkholderia from Stenotrophomonas include:
a. gram stain reaction
b. growth on MAC
c. glucose fermentation
d. oxidase - Answer-d. oxidase
-Stenotrophomonas is oxidase neg
A 17yo female with cystic fibrosis is diagnosed with pneumonia. A sputum sample grew
gram neg bacilli with yellow, smooth colonies that have the following biochemical
reactions:
oxidase: +
TSI: alk/alk
glucose: Oxidized
fluorescence: -
lysine decarboxylase: +
The most likely organism is:
a. Burkholderia cepacia
b. Klebsiella pneumoniae
c. Shewanella putrefaciens
d. Stenotrophomonas maltophilia - Answer-a. Burkholderia cepacia
Characteristics of HACEK group of bacteria include:
a. association with urinary tract infections
b. Gram stain of pleomorphic gram-positive bacilli
c. requirement of 5-10% CO2 for growth
d. requirement of 42'C to grow - Answer-c. requirement of 5-10% CO2 for growth
-Haemophilus, Actinobacillus, Cardiobacterium, Eikenella, Kingella
While swimming in a lake near his home, a young boy cut his foot, and an infection
developed. The culture grew nonfastidious gram negative, oxidase pos, beta hemolytic,
motile bacilli that produced deoxyribonuclease. The most likely ID is:
a. Enterobacter cloacae
,b. Serratia marcescens
c. Aeromonas hydrophila
d. Escherichia coli - Answer-c. Aeromonas hydrophila
-Enterobacteriaceae (E. coli), serratia and Enterobacter are oxidase neg
The lab received a blood culture from a vet who has been ill for many weeks with fevers
in the afternoon and evenings, arthritis, and fatigue. The blood culture is positive after 5
days, and the organism has the following characteristics;
gram stain: small, gram negative coccobacilli
BAP: growth after 48 hours with small, smooth, raised colonies
What should the microbiologist do next?
a. consider the growth contaminated and perform another GS
b. perform biochemical identification for HACEK organisms
c. perform ID and susceptibility testing using an automated system
d. take extra safety precautions for possible Brucella - Answer-d. take extra safety
precautions for possible Brucella
-Brucella causes undulant fever
The primary isolation of Neisseria gonorrhoea requires:
a. anaerobic conditions
b. starch media
c. carbon dioxide
d. blood agar - Answer-c. CO2
An urethral swab obtained from a man with an urethral exudate was plated directly on
CHOC and modified TM and a gram stain was made. THe GS showed Gram negative
diplococci. The culture plates were incubated at 35'C, but had no growth at 48 hrs. The
most likely failure for organism growth is that the:
a. wrong media were used
b. GS was misread
c. organism only grows at RT
d. organism required CO2 for growth - Answer-d. organism required CO2 for growth
Coagulation is associated with:
a. Chlamydia trachomatis
b. Neisseria gonorrhoeae
c. Streptococcus pneumoniae
d. Klebsiella pneumoniae - Answer-b. Neisseria gonorrhoeae
Clinical resistance to penicillin correlates most frequently with beta-lactamase
production is:
a. Neisseria gonorrhoeae
b. Neisseria meningitidis
c. Streptococcus agalactiae
d. Streptococcus pyogenes - Answer-a. Neisseria gonorrhoeae
, All species of the genus Neisseria have the enzyme to oxidize:
a. naphthylamine
b. dimethylaminobenzaldehyde
c. glucopyranoside
d. tetramethyl-phenylenediamine - Answer-d. tetramethyl-phenylenediamine
The diagnosis of Neisseria gonorrhoeae in females is best made from:
a. clinical history
b. an endocervical culture
c. a gram stain of cervical secretions
d. examination for clue cells - Answer-b. an endocervical culture
Which of the following is the most reliable test to differentiate Neisseria lactamica from
Neisseria meningitidis?
a. acid from maltose
b. growth on modified TM
c. lactose degradation
d. nitrite reduction to nitrogen gas - Answer-c. lactose degradation
An autopsy performed on an 8yo child revealed Waterhouse-Friderichsen syndrome.
Blood and throat cultures taken just prior to death were positive for which organism?
a. Neisseria gonorrhoeae
b. Neisseria meningitidis
c. Haemophilus influenzae
d. Klebsiella pneumoniae - Answer-b. Neisseria meningitidis
-Waterhouse-Friderichsen is sever complication of N. meningitidis infection
An aspirated specimen of purulent material was obtained from a brain abscess. After 24
hours incubation, pinpoint colonies grew on sheep blood and small, yellowish colonies
grew on chocolate. Gram stain of the organism showed gram-negative cocci. Results of
carbohydrate degradation studies were as follows:
glucose: acid
maltose: acid
sucrose: acid
lactose: negative
Additional testing revealed the organism was oxidase positive and beta-galactosidase
negative. The organism is most likely neisseria:
a. meningitidis
b. sicca
c. lactamica
d. gonorrhoeae - Answer-b. sicca
An organism recovered from a sputum has the following characteristics:
culture: growth at 7 days on Lowenstein-Jensen agar, incubated under aerobic
conditions with CO2 at 35'C
with 100% Correct Answers 2025 Latest
Update
An aerobic, gram negative coccobacillus was isolated on Bordet-Gengou agar from a
nasopharangeal swab 48 hours after culture from a 6mo infant with suspected
pertussis. The organism exhibited the following characteristics:
MAC: no growth
urea: negative at 4hrs, pos at 24 hrs
oxidase: -
catalase: +
the most probably ID of this isolate is:
a. Moraxella lacunata
b. Pasteurella ureae
c. Bordetella pertussis
d. Boretella parapertussis - Answer-d. Boretella parapertussis
-B pertussis is oxidase pos, urea neg
Which of the following characteristics best differentiates Bordetella bronchiseptica from
Alcaligenes species?
a. flagellar pattern
b. growth at 24'C
c. oxidase activity
d. rapid hydrolysis of urea - Answer-d. rapid hydrolysis of urea
-Bronchiseptica is urea pos within 4 hours
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 nalidixic acid agar
c. Mueller-Hinton agar with 5% sheep blood agar
d. Regan-Lowe media - Answer-a. a media with cysteine such as buffered charcoal
yeast extract agar
-Francisella requires cysteine
A child was butten on the arm by her sibling and the resulting wound grew a slender
gram-negative bacilli that has the following characteristics:
growth on SBA: colonies that "pit" the agar
colonies odor: like bleach
catalase: -
,oxidase: +
TSI: no growth
The ID of this organism is:
a. Moraxella catarrhalis
b. Eikenella corrodens
c. Kingella kingae
d. Legionella pneumophila - Answer-b. Eikenella corrodens
Characteristics of the genus Capnocytophagia include:
a. grows in ambient air
b. colonies are large and spreading after 2-4 days
c. considered "nonfermenter"
d. gram positive bacillus - Answer-b. colonies are large and spreading after 2-4 days
Differentiating tests that will separate Burkholderia from Stenotrophomonas include:
a. gram stain reaction
b. growth on MAC
c. glucose fermentation
d. oxidase - Answer-d. oxidase
-Stenotrophomonas is oxidase neg
A 17yo female with cystic fibrosis is diagnosed with pneumonia. A sputum sample grew
gram neg bacilli with yellow, smooth colonies that have the following biochemical
reactions:
oxidase: +
TSI: alk/alk
glucose: Oxidized
fluorescence: -
lysine decarboxylase: +
The most likely organism is:
a. Burkholderia cepacia
b. Klebsiella pneumoniae
c. Shewanella putrefaciens
d. Stenotrophomonas maltophilia - Answer-a. Burkholderia cepacia
Characteristics of HACEK group of bacteria include:
a. association with urinary tract infections
b. Gram stain of pleomorphic gram-positive bacilli
c. requirement of 5-10% CO2 for growth
d. requirement of 42'C to grow - Answer-c. requirement of 5-10% CO2 for growth
-Haemophilus, Actinobacillus, Cardiobacterium, Eikenella, Kingella
While swimming in a lake near his home, a young boy cut his foot, and an infection
developed. The culture grew nonfastidious gram negative, oxidase pos, beta hemolytic,
motile bacilli that produced deoxyribonuclease. The most likely ID is:
a. Enterobacter cloacae
,b. Serratia marcescens
c. Aeromonas hydrophila
d. Escherichia coli - Answer-c. Aeromonas hydrophila
-Enterobacteriaceae (E. coli), serratia and Enterobacter are oxidase neg
The lab received a blood culture from a vet who has been ill for many weeks with fevers
in the afternoon and evenings, arthritis, and fatigue. The blood culture is positive after 5
days, and the organism has the following characteristics;
gram stain: small, gram negative coccobacilli
BAP: growth after 48 hours with small, smooth, raised colonies
What should the microbiologist do next?
a. consider the growth contaminated and perform another GS
b. perform biochemical identification for HACEK organisms
c. perform ID and susceptibility testing using an automated system
d. take extra safety precautions for possible Brucella - Answer-d. take extra safety
precautions for possible Brucella
-Brucella causes undulant fever
The primary isolation of Neisseria gonorrhoea requires:
a. anaerobic conditions
b. starch media
c. carbon dioxide
d. blood agar - Answer-c. CO2
An urethral swab obtained from a man with an urethral exudate was plated directly on
CHOC and modified TM and a gram stain was made. THe GS showed Gram negative
diplococci. The culture plates were incubated at 35'C, but had no growth at 48 hrs. The
most likely failure for organism growth is that the:
a. wrong media were used
b. GS was misread
c. organism only grows at RT
d. organism required CO2 for growth - Answer-d. organism required CO2 for growth
Coagulation is associated with:
a. Chlamydia trachomatis
b. Neisseria gonorrhoeae
c. Streptococcus pneumoniae
d. Klebsiella pneumoniae - Answer-b. Neisseria gonorrhoeae
Clinical resistance to penicillin correlates most frequently with beta-lactamase
production is:
a. Neisseria gonorrhoeae
b. Neisseria meningitidis
c. Streptococcus agalactiae
d. Streptococcus pyogenes - Answer-a. Neisseria gonorrhoeae
, All species of the genus Neisseria have the enzyme to oxidize:
a. naphthylamine
b. dimethylaminobenzaldehyde
c. glucopyranoside
d. tetramethyl-phenylenediamine - Answer-d. tetramethyl-phenylenediamine
The diagnosis of Neisseria gonorrhoeae in females is best made from:
a. clinical history
b. an endocervical culture
c. a gram stain of cervical secretions
d. examination for clue cells - Answer-b. an endocervical culture
Which of the following is the most reliable test to differentiate Neisseria lactamica from
Neisseria meningitidis?
a. acid from maltose
b. growth on modified TM
c. lactose degradation
d. nitrite reduction to nitrogen gas - Answer-c. lactose degradation
An autopsy performed on an 8yo child revealed Waterhouse-Friderichsen syndrome.
Blood and throat cultures taken just prior to death were positive for which organism?
a. Neisseria gonorrhoeae
b. Neisseria meningitidis
c. Haemophilus influenzae
d. Klebsiella pneumoniae - Answer-b. Neisseria meningitidis
-Waterhouse-Friderichsen is sever complication of N. meningitidis infection
An aspirated specimen of purulent material was obtained from a brain abscess. After 24
hours incubation, pinpoint colonies grew on sheep blood and small, yellowish colonies
grew on chocolate. Gram stain of the organism showed gram-negative cocci. Results of
carbohydrate degradation studies were as follows:
glucose: acid
maltose: acid
sucrose: acid
lactose: negative
Additional testing revealed the organism was oxidase positive and beta-galactosidase
negative. The organism is most likely neisseria:
a. meningitidis
b. sicca
c. lactamica
d. gonorrhoeae - Answer-b. sicca
An organism recovered from a sputum has the following characteristics:
culture: growth at 7 days on Lowenstein-Jensen agar, incubated under aerobic
conditions with CO2 at 35'C
