BOC Microbiology Practice Questions with 100%
Correct Answers to guarantee A+| Verified |
A CSF culture from an immunocompromised patient grew gram-negative coccobacilli on
chocolate agar. Further testing revealed the following:
Motility = -, Indophenol Oxidase = +, MacConkey = no growth
Antibiotic testing showed that it was highly susceptible to penicillin. Which of the
following organisms is most likely present?
- Pseudomonas stutzeri
- Moraxella lacunata
- Acinetobacter spp
- Pseudomonas aeruginosa - ✔✔Moraxella lacunata
A medical technologist receives a stool specimen on a patient with diarrhea who has
just returned from visiting South America. The patient is suspected of having an
infection caused by Vibrio cholerae. Which of the following media would be best for the
identification and recovery of this organism?
- Blood agar
- TCBS agar
- XLD agar
- MacConkey agar - ✔✔TCBS agar
A gram negative, non-lactose fermenter was recovered from a culture from patient
suffering from 2nd degree burns. Which of the following tests would best differentiate
Acinetobacter spp and Pseudomonas aeruginosa?
- String test and coagulase test
- Growth on MacConkey, catalase, growth at 37C
,- Motility, oxidase, growth at 42C
- Growth on blood agar, oxidase, growth at 35C - ✔✔Motility, oxidase, growth at 42C
Cultures from a hospital hot water system gave the following results:
Growth at 42C = +
Growth on Lowenstein-Jensen medium = no pigmentation after exposure to light
Niacin accumulation = -
Nitrate reduction test = -
Which of the following organisms is most likely present?
- Mycobacterium marinum
- Mycobacterium haemophilum
- Mycobacterium ulcerans
- Mycobacterium xenopi - ✔✔Mycobacterium xenopi
In a nitrate reduction test, a positive result is indicated by a red color change. Which of
the following reagent(s) is (are) used in the reaction?
- Sulfanilic acid and alpha-naphthylamine
- Potassium hydroxide and alpha-naphthol
- o-Nitrophenyl-B-D-galactopyranoside
- Erlich's and Kovac's reagent - ✔✔Sulfanilic acid and alpha-naphthylamine
Which of the following would not be appropriate when collecting a urine for culture?
- The collected sample must be plated within 2 hours unless refrigerated
- The container must be sterile
- The sample may be held at 2C - 8C for up to 48 hours prior to plating
,- The midstream void technique must be used - ✔✔The sample may be held at 2C -
8C for up to 48 hours prior to plating
A culture was ordered on pulmonary secretions from an 8-year-old cystic fibrosis patient
who had come down with pneumonia. Consider the following results from a pure
culture of gram-negative bacilli:
Oxidase = +, Motility = +, Glucose OF (open) = +, Gelatin hydrolysis = +, Growth at 42C =
+, Arginine dihydrolase = +, Pigment = red, non-fluorescent, Flagella = + with polar
monotrichous
Which of the following organisms is most likely responsible for the pneumonia?
- Burkholderia (P.) pseudomallei
- Burkholderia (P.) cepacia
- Pseudomonas aeruginosa
- Pseudomonas stutzeri - ✔✔Pseudomonas aeruginosa
A vaginal swab was cultured using Thayer-Martin media. The colonies that grew stained
as gram-negative diplococci. Additional testing yielded the following results:
Catalase = +, Oxidase = +, Superoxol = -, Glucose = +, Lactose = +, Maltose = +, Sucrose =
-, Fructose = -
Which of the following is most likely present?
- No answer text provided
- Neisseria lactamica
- Neisseria gonorrhoeae
- Neisseria sicca - ✔✔Neisseria lactamica
Blood cultures on a 5-day-old gave the following results:
, Gram stain = gpc in chains, Beta hemolysis, CAMP test = +, Hippurate hydrolysis = -, Salt
tolerance = +, Bile solubility = -, Bile esculin = -, Bacitracin = resistant, PYR = -,
Trimethoprim/sulfamthoxazole = resistant
Which of the following is most likely present?
- Group B streptococci
- Group D streptococci
- Group A streptococci
- Nongroup A, nongroup B, nongroup D streptococci - ✔✔Group B streptococci
Which of the following is true regarding Streptococcus spp?
- Facultative anaerobe, oxidase-negative, catalase-negative
- Aerobic, oxidase-positive, and catalase-positive
- Facultative anaerobe, beta hemolytic, catalase-positive
- May be alpha, beta, or gamma hemolytic, catalase-positive - ✔✔Facultative
anaerobe, oxidase-negative, catalase-negative
A swab from a diabetic ulcer is sent to the lab for culture and yields the following
results:
Colony morph = creamy, pale yellow, B-hemolytic colonies on BAP, Catalase = +, Glucose
OF = open tube +, sealed tube -, Mannitol salt = - Slide coagulase = -
Which of the following is likely present?
- Micrococcus spp
- Staphylococcus epidermidis
- Staphylococcus aureus
- Streptococcus spp - ✔✔Micrococcus spp
Correct Answers to guarantee A+| Verified |
A CSF culture from an immunocompromised patient grew gram-negative coccobacilli on
chocolate agar. Further testing revealed the following:
Motility = -, Indophenol Oxidase = +, MacConkey = no growth
Antibiotic testing showed that it was highly susceptible to penicillin. Which of the
following organisms is most likely present?
- Pseudomonas stutzeri
- Moraxella lacunata
- Acinetobacter spp
- Pseudomonas aeruginosa - ✔✔Moraxella lacunata
A medical technologist receives a stool specimen on a patient with diarrhea who has
just returned from visiting South America. The patient is suspected of having an
infection caused by Vibrio cholerae. Which of the following media would be best for the
identification and recovery of this organism?
- Blood agar
- TCBS agar
- XLD agar
- MacConkey agar - ✔✔TCBS agar
A gram negative, non-lactose fermenter was recovered from a culture from patient
suffering from 2nd degree burns. Which of the following tests would best differentiate
Acinetobacter spp and Pseudomonas aeruginosa?
- String test and coagulase test
- Growth on MacConkey, catalase, growth at 37C
,- Motility, oxidase, growth at 42C
- Growth on blood agar, oxidase, growth at 35C - ✔✔Motility, oxidase, growth at 42C
Cultures from a hospital hot water system gave the following results:
Growth at 42C = +
Growth on Lowenstein-Jensen medium = no pigmentation after exposure to light
Niacin accumulation = -
Nitrate reduction test = -
Which of the following organisms is most likely present?
- Mycobacterium marinum
- Mycobacterium haemophilum
- Mycobacterium ulcerans
- Mycobacterium xenopi - ✔✔Mycobacterium xenopi
In a nitrate reduction test, a positive result is indicated by a red color change. Which of
the following reagent(s) is (are) used in the reaction?
- Sulfanilic acid and alpha-naphthylamine
- Potassium hydroxide and alpha-naphthol
- o-Nitrophenyl-B-D-galactopyranoside
- Erlich's and Kovac's reagent - ✔✔Sulfanilic acid and alpha-naphthylamine
Which of the following would not be appropriate when collecting a urine for culture?
- The collected sample must be plated within 2 hours unless refrigerated
- The container must be sterile
- The sample may be held at 2C - 8C for up to 48 hours prior to plating
,- The midstream void technique must be used - ✔✔The sample may be held at 2C -
8C for up to 48 hours prior to plating
A culture was ordered on pulmonary secretions from an 8-year-old cystic fibrosis patient
who had come down with pneumonia. Consider the following results from a pure
culture of gram-negative bacilli:
Oxidase = +, Motility = +, Glucose OF (open) = +, Gelatin hydrolysis = +, Growth at 42C =
+, Arginine dihydrolase = +, Pigment = red, non-fluorescent, Flagella = + with polar
monotrichous
Which of the following organisms is most likely responsible for the pneumonia?
- Burkholderia (P.) pseudomallei
- Burkholderia (P.) cepacia
- Pseudomonas aeruginosa
- Pseudomonas stutzeri - ✔✔Pseudomonas aeruginosa
A vaginal swab was cultured using Thayer-Martin media. The colonies that grew stained
as gram-negative diplococci. Additional testing yielded the following results:
Catalase = +, Oxidase = +, Superoxol = -, Glucose = +, Lactose = +, Maltose = +, Sucrose =
-, Fructose = -
Which of the following is most likely present?
- No answer text provided
- Neisseria lactamica
- Neisseria gonorrhoeae
- Neisseria sicca - ✔✔Neisseria lactamica
Blood cultures on a 5-day-old gave the following results:
, Gram stain = gpc in chains, Beta hemolysis, CAMP test = +, Hippurate hydrolysis = -, Salt
tolerance = +, Bile solubility = -, Bile esculin = -, Bacitracin = resistant, PYR = -,
Trimethoprim/sulfamthoxazole = resistant
Which of the following is most likely present?
- Group B streptococci
- Group D streptococci
- Group A streptococci
- Nongroup A, nongroup B, nongroup D streptococci - ✔✔Group B streptococci
Which of the following is true regarding Streptococcus spp?
- Facultative anaerobe, oxidase-negative, catalase-negative
- Aerobic, oxidase-positive, and catalase-positive
- Facultative anaerobe, beta hemolytic, catalase-positive
- May be alpha, beta, or gamma hemolytic, catalase-positive - ✔✔Facultative
anaerobe, oxidase-negative, catalase-negative
A swab from a diabetic ulcer is sent to the lab for culture and yields the following
results:
Colony morph = creamy, pale yellow, B-hemolytic colonies on BAP, Catalase = +, Glucose
OF = open tube +, sealed tube -, Mannitol salt = - Slide coagulase = -
Which of the following is likely present?
- Micrococcus spp
- Staphylococcus epidermidis
- Staphylococcus aureus
- Streptococcus spp - ✔✔Micrococcus spp
