BOC Microbiology Practice Questions With
Complete Solutions
A 19-year-old male is suspected of having HSV-2
(genital herpes simplex) infection. Which of the
following tests would provide the most rapid
definitive diagnosis?
- Titer of serum and seminal fluid for antibodies to
herpes simplex
- Cell culture of vesicle fluid
- Direct immunofluorescence test for viral antigen
in vesicle fluid
- Detection of antiheroes simplex in seminal fluid
Correct Answers Direct immunofluorescence test
for viral antigen in vesicle fluid
A 20 mm mature adult fluke that has a normal
habitat in the liver bile ducts. Humans become
infected by ingesting raw or undercooked water
plants contaminated with infective metacercaria.
These adult flukes are only observed during
surgery involving the liver or at autopsy.
Intermittent upper abdominal discomfort and low
grade jaundice may be experienced. Select the
presumptive identification of this fluke.
- Clonorchis sinensis
- Fasciola hepatica
- Faciolopsis buski
- Paragonimus westermani Correct Answers
Fasciola hepatica
,A 21-year-old pregnant woman in her 3rd trimester
was brought to the ED with fever, diarrhea, and
other flulike symptoms. Blood and urine were both
taken for cultures. Urine cultures had no growth
after 24 hours, while blood cultures grew short,
gram-positive rods aerobically on BAP. Consider
the following results from the blood cultures:
Colony morph = smooth and small, similar to Strep
spp, narrow zone of beta hemolysis, Catalase = +,
Motility = + (wet mount = tumbling), Glucose = +
(acid), Esculin hydrolysis = +
Which of the following organisms is most likely
present?
- Streptococcus pneumoniae
- Corynebacterium spp
- Streptococcus agalactiae
- Listeria monocytogenes Correct Answers Listeria
monocytogenes
A 27-year-old female graduate student recently
returned from South America, where she
completed a nature study of the rainforest. She
spent months "living off the land". The women
went to her physician seeking treatment for a sinus
infection, which she thought was responsible for
several recent bouts of diarrhea. Upon questioning
the patient, the doctor decided to collect stool for
culture and parasitic examination. The stool culture
was reported as "no enteric pathogens isolated". A
,suspicious form was seen on both wet prep and on
a permanent stain. It measures 17 um. The identity
of this form is most likely:
- Endolimax nana
- Giardia lamblia
- Iodamoeba butschlii
- Pseudoparasite Correct Answers Iodamoeba
butschlii
A 3-year-old female was seen by a local ear, nose,
and throat specialist for chronic ear pain. She had
been treated several times for otitis media by her
pediatrician with no resolution. Drainage from her
ear grew an acid fast bacillus that gave the
following biochemical reactions:
Iron uptake +, Nitrate reduction +, Arylsulfatase +,
MAC growth 5 days +
It should be identified as:
- M. avium complex
- M. fortuitum
- M. chelonae
- M. kansasii Correct Answers M. fortuitum
A 48-year-old male transplant patient arrived in the
Emergency Department complaining of
neurological difficulties after having a pulmonary
infection. A lumbar puncture was performed and
cloudy CSF was obtained, from which a gram-stain
revealed gram positive long beaded bacilli. An
, acid-fast smear showed filamentous partially acid-
fast bacilli. Which organism is most likely present?
- Mycobacterium avium
- Mycobacterium bovis
- Nocardia asteroides
- Legionella spp. Correct Answers Nocardia
asteroides
A 58-year-old patient from Brazil with a history of
congestive heart failure (CHF) and cardiac
irregularities dies suddenly. Mycobacterium
examination reveals the presence of many
amastigotes. Which of the following is most likely
the cause of death?
- Trypanosomiasis with Trypanosoma gambiense
- Leishmaniasis with Leishmania donovani
- Trypanosomiasis with Trypanosoma cruzi
- Leishmaniasis with Leishmania braziliense
Correct Answers Trypanosomiasis with
Trypanosoma cruzi
A 62-year-old female undergoing chemotherapy for
breast cancer developed fever, abdominal pain,
and foul-smelling diarrhea after receiving
clindamycin for 5 days. The H&E stained section of
colon biopsy reveals focal ulceration and
pseudomembranous inflammation. Each of the
following lab findings will confirm the presumptive
diagnosis of Clostridium difficile-associated colitis
except:
Complete Solutions
A 19-year-old male is suspected of having HSV-2
(genital herpes simplex) infection. Which of the
following tests would provide the most rapid
definitive diagnosis?
- Titer of serum and seminal fluid for antibodies to
herpes simplex
- Cell culture of vesicle fluid
- Direct immunofluorescence test for viral antigen
in vesicle fluid
- Detection of antiheroes simplex in seminal fluid
Correct Answers Direct immunofluorescence test
for viral antigen in vesicle fluid
A 20 mm mature adult fluke that has a normal
habitat in the liver bile ducts. Humans become
infected by ingesting raw or undercooked water
plants contaminated with infective metacercaria.
These adult flukes are only observed during
surgery involving the liver or at autopsy.
Intermittent upper abdominal discomfort and low
grade jaundice may be experienced. Select the
presumptive identification of this fluke.
- Clonorchis sinensis
- Fasciola hepatica
- Faciolopsis buski
- Paragonimus westermani Correct Answers
Fasciola hepatica
,A 21-year-old pregnant woman in her 3rd trimester
was brought to the ED with fever, diarrhea, and
other flulike symptoms. Blood and urine were both
taken for cultures. Urine cultures had no growth
after 24 hours, while blood cultures grew short,
gram-positive rods aerobically on BAP. Consider
the following results from the blood cultures:
Colony morph = smooth and small, similar to Strep
spp, narrow zone of beta hemolysis, Catalase = +,
Motility = + (wet mount = tumbling), Glucose = +
(acid), Esculin hydrolysis = +
Which of the following organisms is most likely
present?
- Streptococcus pneumoniae
- Corynebacterium spp
- Streptococcus agalactiae
- Listeria monocytogenes Correct Answers Listeria
monocytogenes
A 27-year-old female graduate student recently
returned from South America, where she
completed a nature study of the rainforest. She
spent months "living off the land". The women
went to her physician seeking treatment for a sinus
infection, which she thought was responsible for
several recent bouts of diarrhea. Upon questioning
the patient, the doctor decided to collect stool for
culture and parasitic examination. The stool culture
was reported as "no enteric pathogens isolated". A
,suspicious form was seen on both wet prep and on
a permanent stain. It measures 17 um. The identity
of this form is most likely:
- Endolimax nana
- Giardia lamblia
- Iodamoeba butschlii
- Pseudoparasite Correct Answers Iodamoeba
butschlii
A 3-year-old female was seen by a local ear, nose,
and throat specialist for chronic ear pain. She had
been treated several times for otitis media by her
pediatrician with no resolution. Drainage from her
ear grew an acid fast bacillus that gave the
following biochemical reactions:
Iron uptake +, Nitrate reduction +, Arylsulfatase +,
MAC growth 5 days +
It should be identified as:
- M. avium complex
- M. fortuitum
- M. chelonae
- M. kansasii Correct Answers M. fortuitum
A 48-year-old male transplant patient arrived in the
Emergency Department complaining of
neurological difficulties after having a pulmonary
infection. A lumbar puncture was performed and
cloudy CSF was obtained, from which a gram-stain
revealed gram positive long beaded bacilli. An
, acid-fast smear showed filamentous partially acid-
fast bacilli. Which organism is most likely present?
- Mycobacterium avium
- Mycobacterium bovis
- Nocardia asteroides
- Legionella spp. Correct Answers Nocardia
asteroides
A 58-year-old patient from Brazil with a history of
congestive heart failure (CHF) and cardiac
irregularities dies suddenly. Mycobacterium
examination reveals the presence of many
amastigotes. Which of the following is most likely
the cause of death?
- Trypanosomiasis with Trypanosoma gambiense
- Leishmaniasis with Leishmania donovani
- Trypanosomiasis with Trypanosoma cruzi
- Leishmaniasis with Leishmania braziliense
Correct Answers Trypanosomiasis with
Trypanosoma cruzi
A 62-year-old female undergoing chemotherapy for
breast cancer developed fever, abdominal pain,
and foul-smelling diarrhea after receiving
clindamycin for 5 days. The H&E stained section of
colon biopsy reveals focal ulceration and
pseudomembranous inflammation. Each of the
following lab findings will confirm the presumptive
diagnosis of Clostridium difficile-associated colitis
except:
