BOC Prep 7 Pro Test Questions With
Solved Solutions.
In a quality control procedure on a new batch of Mueller-Hinton agar plates using a stock culture of S.
aureus, all the disk zone sizes are too small. The most likely reason for this is that:
A. potency of the antibiotic disks is too high
B. Mueller-Hinton plates were poured too thin
C. disks should have been set up on mannitol salt
D. bacterial suspension was not diluted to the proper concentration - Answer D. bacterial suspension
was not diluted to the proper concentration
Which of the following combinations of organisms would be appropriate as controls to test the functions
listed?
A. beta-hemolysis - negative Escherichia coli and Streptococcus pyogenes
B. indole - negative Escherichia coli and Proteus mirabilis
C. H2S production - negative Proteus mirabilis and Staphylococcus epidermidis
D. catalase - negative Staphylococcus aureus and Staphylococcus epidermidis - Answer B. indole -
negative Escherichia coli and Proteus mirabilis
A urine Gram stain shows gram-positive cocci in clusters. The organism tested catalase positive. To
speciate this organism from culture, the technician should perform a coagulase test and a/an:
A. oxidase
B. beta-lactamase
C. novobiocin susceptibility
D. polymyxin B susceptibility - Answer C. novobiocin susceptibility
,The Gram stain from a blood culture shows gram-positive cocci in chains. No growth occurs on blood
agar plates incubated both aerobically and anaerobically. Additional testing should be done
to detect the presence of:
A. Streptococcus pneumonia
B. Abiotrophia defective
C. Staphylococcus saprophyticus
D. Aerococcus urinae - Answer B. Abiotrophia defective
Viridans streptococci can be differentiated from Streptococcus pneumoniae by:
A. alpha hemolysis
B. catalase reaction
C. morphology
D. bile solubility - Answer D. bile solubility
A reliable test for distinguishing Staphylococcus aureus from other staphylococci is:
A. coagulase
B. catalase
C. optochin susceptibility
D. oxidase - Answer B. catalase
The optochin (ethylhydrocupreine hydrochloride) disk is used for the identification of:
A. Haemophilus influenzae
B. Streptococcus pneumoniae
C. group A beta-hemolytic streptococci
D. alpha-hemolytic streptococci - Answer B. Streptococcus pneumoniae
, In the optochin (ethylhydrocupreine hydrochloride) susceptibility test, if there is a zone of inhibition of
19-30 mm surrounding the disk following overnight incubation at 37"C, the colony most likely consists of:
A. intestinal bacilli
B. pneumococci
C. streptococci
D. staphylococci - Answer B. pneumococci
Which 2 diseases are usually preceded by infection with beta-hemolytic streptococci?
A. rheumatic fever, undulant fever
B. glomerulonephritis, rheumatic fever
C. glomerulonephritis, undulant fever
D. rheumatic fever, tularemia - Answer B. glomerulonephritis, rheumatic fever
The enterotoxin produced by certain strains of hemolytic, coagulase-positive Staphylococcus aureus:
A. is identical to the dermonecrotic toxin
B. is destroyed by boiling for 15-30 minutes
C. causes one type of bacterial food poisoning
D. is highly antigenic - Answer C. causes one type of bacterial food poisoning
A gamma-hemolytic Streptococcus that blackens bile esculin agar but does not grow in 6.5% NaCl broth
is most likely:
A. Enterococcus
B. group D Streptococcus
C. group B Streptococcus
Solved Solutions.
In a quality control procedure on a new batch of Mueller-Hinton agar plates using a stock culture of S.
aureus, all the disk zone sizes are too small. The most likely reason for this is that:
A. potency of the antibiotic disks is too high
B. Mueller-Hinton plates were poured too thin
C. disks should have been set up on mannitol salt
D. bacterial suspension was not diluted to the proper concentration - Answer D. bacterial suspension
was not diluted to the proper concentration
Which of the following combinations of organisms would be appropriate as controls to test the functions
listed?
A. beta-hemolysis - negative Escherichia coli and Streptococcus pyogenes
B. indole - negative Escherichia coli and Proteus mirabilis
C. H2S production - negative Proteus mirabilis and Staphylococcus epidermidis
D. catalase - negative Staphylococcus aureus and Staphylococcus epidermidis - Answer B. indole -
negative Escherichia coli and Proteus mirabilis
A urine Gram stain shows gram-positive cocci in clusters. The organism tested catalase positive. To
speciate this organism from culture, the technician should perform a coagulase test and a/an:
A. oxidase
B. beta-lactamase
C. novobiocin susceptibility
D. polymyxin B susceptibility - Answer C. novobiocin susceptibility
,The Gram stain from a blood culture shows gram-positive cocci in chains. No growth occurs on blood
agar plates incubated both aerobically and anaerobically. Additional testing should be done
to detect the presence of:
A. Streptococcus pneumonia
B. Abiotrophia defective
C. Staphylococcus saprophyticus
D. Aerococcus urinae - Answer B. Abiotrophia defective
Viridans streptococci can be differentiated from Streptococcus pneumoniae by:
A. alpha hemolysis
B. catalase reaction
C. morphology
D. bile solubility - Answer D. bile solubility
A reliable test for distinguishing Staphylococcus aureus from other staphylococci is:
A. coagulase
B. catalase
C. optochin susceptibility
D. oxidase - Answer B. catalase
The optochin (ethylhydrocupreine hydrochloride) disk is used for the identification of:
A. Haemophilus influenzae
B. Streptococcus pneumoniae
C. group A beta-hemolytic streptococci
D. alpha-hemolytic streptococci - Answer B. Streptococcus pneumoniae
, In the optochin (ethylhydrocupreine hydrochloride) susceptibility test, if there is a zone of inhibition of
19-30 mm surrounding the disk following overnight incubation at 37"C, the colony most likely consists of:
A. intestinal bacilli
B. pneumococci
C. streptococci
D. staphylococci - Answer B. pneumococci
Which 2 diseases are usually preceded by infection with beta-hemolytic streptococci?
A. rheumatic fever, undulant fever
B. glomerulonephritis, rheumatic fever
C. glomerulonephritis, undulant fever
D. rheumatic fever, tularemia - Answer B. glomerulonephritis, rheumatic fever
The enterotoxin produced by certain strains of hemolytic, coagulase-positive Staphylococcus aureus:
A. is identical to the dermonecrotic toxin
B. is destroyed by boiling for 15-30 minutes
C. causes one type of bacterial food poisoning
D. is highly antigenic - Answer C. causes one type of bacterial food poisoning
A gamma-hemolytic Streptococcus that blackens bile esculin agar but does not grow in 6.5% NaCl broth
is most likely:
A. Enterococcus
B. group D Streptococcus
C. group B Streptococcus
