Clinical Microbiology- Final Exam
Questions with Guaranteed Pass
Solutions 2025-2026 Updated.
Rejection of inappropriately collected or transported specimens - Answer should be initiated
by laboratory personnel but approved by nursing or physician staff responsible for the care of
the patient.
Anaerobes grow best in - Answer Five percent to 10% hydrogen (H2), 5% to 10% CO2, 80% to
90% nitrogen (N2), and 0% O2.
To be sterilized in an autoclave, infectious medical waste should be: - Answer processed for
30 to 60 minutes at 132°C and 15 psi pressure.
The definitive identification of clinically significant isolates is: - Answer desirable in most
cases; however, limited identification may sometimes be necessary and helpful.
The microbiology laboratory receives a genital culture from a 28-year-old female. The specimen
direct Gram stain reveals, gram-positive cocci in clusters and gram-negative cocci in chains. The
microbiologist inoculates a sheep blood agar plate, a chocolate agar plate, a modified thayer
martin plate and a LIM Broth (selective enrichment for group B streptococci). The second shift
microbiologist identifies the discrepancy and must take corrective action. The discrepancy
indicates: - Answer the preliminary Gram stain was erroneously reported.
The agency that published guidelines known as Standard Precautions to reduce the risk of
disease transmission in laboratories is - Answer CDC.
Primary plating media for stool include - Answer BA, Mac, HE, Campy
Class II biological safety cabinets - Answer All of the above are correct
Certain procedures require the use of a biological safety cabinet. These include - Answer all
of the above.
Specimens for microbiologic studies should be - Answer All of the above are correct.
Holding media such as Stuart's medium and Amie's medium are used - Answer to maintain
the viability of microorganisms present in a specimen.
,Which type of media is designed to support the growth of a wide range of microorganisms? -
Answer Nutritive
(A) True or (B) False: Reporting or formal documentation of an accident in the lab must be done
FIRST before the healthcare worker receives immediate medical care. - Answer False
The method of choice for sterilizing items such as antibiotic solutions, chemicals, radioisotopes,
and vaccines that are heat-sensitive is: - Answer filtration.
To be sterilized in an autoclave, media or instruments should be: - Answer processed for 15
minutes at 121°C and 15 psi pressure.
Which type of media is designed to support the growth of one group of organisms, but not
another, by containing antimicrobials, dyes, or alcohol? - Answer Selective
The appropriate storage for a cerebral spinal fluid specimen is ____°C. - Answer 37
A principal role of the clinical microbiologist includes: - Answer quickly and accurately
communicating information about the patient in both verbal and written formats.
Routine microbiology cultures should include all of the following media except: - Answer
highly selective specialized media such as Löwenstein-Jensen agar.
Selection of culture media for specific specimens includes a variety of media for all of the
following reasons except: - Answer a back-up broth is included to provide inoculum for
additional testing.
The microbiologist receives a sputum specimen that upon preliminary Gram staining review of
direct smear, contains numerous squamous epithelial cells and an excessive amount of
contaminating normal flora. Based on the microbiologists knowledge, the microbiologist rejects
the specimen and requests a new sample. The physician insists that the microbiologist culture
the sample as received. The microbiologist should: - Answer set-up the culture as ordered
noting the lack of specimen integrity that may compromise culture results.
A definitive identification of a pathogen typically includes: - Answer a confirmatory set of
reactions that correlates to the preliminary characteristics.
The macroscopic examination for receipt and review of specimens should include all of the
following: - Answer leakage, blood or mucus present, viscosity for fluids, color and
consistency.
,An example of a b-hemolytic gram-positive organism is: - Answer Escherichia coli.
Which specimen culture, if positive, should be immediately reported to the clinician? - Answer
Stool
Which specimen is quantitatively plated by using a calibrated loop? - Answer Urine
Between 5% and 10% hydrogen (H2), 5% to 10% CO2, 80% to 90% nitrogen (N2), and 0% O2
produce an environmental condition that best suits which type of organism? - Answer
Anaerobes
Biosafety Level 2 agents - Answer include those that are the common agents of infectious
disease
Procedures such as grinding, mincing, vortexing, and preparing smears - Answer create
aerosol droplets and should be performed only in an approved biosafety cabinet.
The best anticoagulant that can be used to prevent clotting of specimens such as blood, bone
marrow, and synovial fluid that are submitted for recovery of all types of microorganisms is -
Answer sodium polyanethol sulfonate (SPS).
Reduced O2 (5% to 10%) and increased CO2 (8% to 10%) is the environmental condition that
best suits which type of organism? - Answer Microaerophiles
Colonies of Streptococcus pneumoniae appear a-hemolytic on blood agar media. Which one of
the following statements explains this discrepancy? - Answer No discrepancy is present. S.
pneumoniae should be a-hemolytic on blood agar.
An example of a selective medium for gram-positive organisms is: - Answer olistin and
nalidixic acid.
The microbiologist receives a sputum specimen for culture in the microbiology laboratory. Upon
receipt the microbiologist should: - Answer complete a direct Gram stain and preliminary
report.
Increased concentrations of CO2 (5% to 10%) and approximately 15% O2 produce an
environmental condition that best suits which type of organism? - Answer Capnophiles
, A candle jar is used to cultivate which type of bacteria? - Answer Capnophiles
Which organism is catalase positive, coagulase negative, pyrrolidonyl arylamidase (PYR) positive,
susceptible to novobiocin, urease negative, and b-hemolytic on sheep blood agar? - Answer
S. haemolyticus
The resident human microbiota, staphylococcus, which is more likely to cause infections in
compromised hosts such as patients with cancer, is: - Answer S. epidermidis.
Rejection of inappropriately collected or transported specimens: - Answer should be
initiated by laboratory personnel but approved by the nurses or physicians responsible for the
care of the patient.
Clinical sensitivity in the microbiology laboratory refers to: - Answer positive results from
patients known to have an infection or disease.
Which category of media can be described as containing nutrients that support the growth of
the most nonfastidious organisms without giving any particular organism a growth advantage? -
Answer Supportive
Which medium can be described as containing crystal violet dye to inhibit the growth of gram-
positive bacteria and fungi and allows many types of gram-negative bacilli to grow? - Answer
MacConkey agar
Which virulent and important human pathogen can also be recovered from the nares,
perineum, and other skin sites of healthy people, especially in the hospital setting? - Answer
S. aureus
A urine specimen was collected at 8 a.m. The nurse labeled the sample and placed it next to the
tube station to be sent to the laboratory for testing. The specimen was received in the
laboratory for culture at 1 p.m. on the same day. The microbiologist should: - Answer Call
the nurse to explain why the specimen was rejected and request a new sample
Biosafety Level 1 agents: - Answer require only standard good laboratory technique.
The role of the agar ingredient in culture medium is to: - Answer solidify the medium and
provide a stable culture surface
Which group of bacteria is described as catalase positive and is gram-positive cocci that grow
facultatively anaerobic and form grapelike clusters? - Answer Staphylococcus
Questions with Guaranteed Pass
Solutions 2025-2026 Updated.
Rejection of inappropriately collected or transported specimens - Answer should be initiated
by laboratory personnel but approved by nursing or physician staff responsible for the care of
the patient.
Anaerobes grow best in - Answer Five percent to 10% hydrogen (H2), 5% to 10% CO2, 80% to
90% nitrogen (N2), and 0% O2.
To be sterilized in an autoclave, infectious medical waste should be: - Answer processed for
30 to 60 minutes at 132°C and 15 psi pressure.
The definitive identification of clinically significant isolates is: - Answer desirable in most
cases; however, limited identification may sometimes be necessary and helpful.
The microbiology laboratory receives a genital culture from a 28-year-old female. The specimen
direct Gram stain reveals, gram-positive cocci in clusters and gram-negative cocci in chains. The
microbiologist inoculates a sheep blood agar plate, a chocolate agar plate, a modified thayer
martin plate and a LIM Broth (selective enrichment for group B streptococci). The second shift
microbiologist identifies the discrepancy and must take corrective action. The discrepancy
indicates: - Answer the preliminary Gram stain was erroneously reported.
The agency that published guidelines known as Standard Precautions to reduce the risk of
disease transmission in laboratories is - Answer CDC.
Primary plating media for stool include - Answer BA, Mac, HE, Campy
Class II biological safety cabinets - Answer All of the above are correct
Certain procedures require the use of a biological safety cabinet. These include - Answer all
of the above.
Specimens for microbiologic studies should be - Answer All of the above are correct.
Holding media such as Stuart's medium and Amie's medium are used - Answer to maintain
the viability of microorganisms present in a specimen.
,Which type of media is designed to support the growth of a wide range of microorganisms? -
Answer Nutritive
(A) True or (B) False: Reporting or formal documentation of an accident in the lab must be done
FIRST before the healthcare worker receives immediate medical care. - Answer False
The method of choice for sterilizing items such as antibiotic solutions, chemicals, radioisotopes,
and vaccines that are heat-sensitive is: - Answer filtration.
To be sterilized in an autoclave, media or instruments should be: - Answer processed for 15
minutes at 121°C and 15 psi pressure.
Which type of media is designed to support the growth of one group of organisms, but not
another, by containing antimicrobials, dyes, or alcohol? - Answer Selective
The appropriate storage for a cerebral spinal fluid specimen is ____°C. - Answer 37
A principal role of the clinical microbiologist includes: - Answer quickly and accurately
communicating information about the patient in both verbal and written formats.
Routine microbiology cultures should include all of the following media except: - Answer
highly selective specialized media such as Löwenstein-Jensen agar.
Selection of culture media for specific specimens includes a variety of media for all of the
following reasons except: - Answer a back-up broth is included to provide inoculum for
additional testing.
The microbiologist receives a sputum specimen that upon preliminary Gram staining review of
direct smear, contains numerous squamous epithelial cells and an excessive amount of
contaminating normal flora. Based on the microbiologists knowledge, the microbiologist rejects
the specimen and requests a new sample. The physician insists that the microbiologist culture
the sample as received. The microbiologist should: - Answer set-up the culture as ordered
noting the lack of specimen integrity that may compromise culture results.
A definitive identification of a pathogen typically includes: - Answer a confirmatory set of
reactions that correlates to the preliminary characteristics.
The macroscopic examination for receipt and review of specimens should include all of the
following: - Answer leakage, blood or mucus present, viscosity for fluids, color and
consistency.
,An example of a b-hemolytic gram-positive organism is: - Answer Escherichia coli.
Which specimen culture, if positive, should be immediately reported to the clinician? - Answer
Stool
Which specimen is quantitatively plated by using a calibrated loop? - Answer Urine
Between 5% and 10% hydrogen (H2), 5% to 10% CO2, 80% to 90% nitrogen (N2), and 0% O2
produce an environmental condition that best suits which type of organism? - Answer
Anaerobes
Biosafety Level 2 agents - Answer include those that are the common agents of infectious
disease
Procedures such as grinding, mincing, vortexing, and preparing smears - Answer create
aerosol droplets and should be performed only in an approved biosafety cabinet.
The best anticoagulant that can be used to prevent clotting of specimens such as blood, bone
marrow, and synovial fluid that are submitted for recovery of all types of microorganisms is -
Answer sodium polyanethol sulfonate (SPS).
Reduced O2 (5% to 10%) and increased CO2 (8% to 10%) is the environmental condition that
best suits which type of organism? - Answer Microaerophiles
Colonies of Streptococcus pneumoniae appear a-hemolytic on blood agar media. Which one of
the following statements explains this discrepancy? - Answer No discrepancy is present. S.
pneumoniae should be a-hemolytic on blood agar.
An example of a selective medium for gram-positive organisms is: - Answer olistin and
nalidixic acid.
The microbiologist receives a sputum specimen for culture in the microbiology laboratory. Upon
receipt the microbiologist should: - Answer complete a direct Gram stain and preliminary
report.
Increased concentrations of CO2 (5% to 10%) and approximately 15% O2 produce an
environmental condition that best suits which type of organism? - Answer Capnophiles
, A candle jar is used to cultivate which type of bacteria? - Answer Capnophiles
Which organism is catalase positive, coagulase negative, pyrrolidonyl arylamidase (PYR) positive,
susceptible to novobiocin, urease negative, and b-hemolytic on sheep blood agar? - Answer
S. haemolyticus
The resident human microbiota, staphylococcus, which is more likely to cause infections in
compromised hosts such as patients with cancer, is: - Answer S. epidermidis.
Rejection of inappropriately collected or transported specimens: - Answer should be
initiated by laboratory personnel but approved by the nurses or physicians responsible for the
care of the patient.
Clinical sensitivity in the microbiology laboratory refers to: - Answer positive results from
patients known to have an infection or disease.
Which category of media can be described as containing nutrients that support the growth of
the most nonfastidious organisms without giving any particular organism a growth advantage? -
Answer Supportive
Which medium can be described as containing crystal violet dye to inhibit the growth of gram-
positive bacteria and fungi and allows many types of gram-negative bacilli to grow? - Answer
MacConkey agar
Which virulent and important human pathogen can also be recovered from the nares,
perineum, and other skin sites of healthy people, especially in the hospital setting? - Answer
S. aureus
A urine specimen was collected at 8 a.m. The nurse labeled the sample and placed it next to the
tube station to be sent to the laboratory for testing. The specimen was received in the
laboratory for culture at 1 p.m. on the same day. The microbiologist should: - Answer Call
the nurse to explain why the specimen was rejected and request a new sample
Biosafety Level 1 agents: - Answer require only standard good laboratory technique.
The role of the agar ingredient in culture medium is to: - Answer solidify the medium and
provide a stable culture surface
Which group of bacteria is described as catalase positive and is gram-positive cocci that grow
facultatively anaerobic and form grapelike clusters? - Answer Staphylococcus
