Test bank Questions already passed
1.
The most frequent agent of nosocomial bacteremia is:
A. catalase-negative micrococci.
B. coagulase-positive staphylococci.
C. catalase-negative stomatococci.
D. coagulase-negative staphylococci- ✔✔✔D
The species of Staphylococcus, which is one of the most important human pathogens, is:
A. S. lentus.
B. S. aureus.
C. S. mucilaginosus.
D. S. intermedius- ✔✔✔B
Which group of bacteria is described as catalase positive and is gram-positive cocci that grow
facultatively anaerobic and form grapelike clusters?
A. Neisseria
B. Rothia (stomatococci)
C. Staphylococcus
D. Micrococcus- ✔✔✔C
The first identification test performed on a clinical isolate of gram-positive, catalase-positive cocci would
likely be the:
A. penicillin test.
B. Gram stain.
,C. oxidase test.
D. coagulase test- ✔✔✔D
The slide coagulase test is a rapid screening test for the production of:
A. clumping factor.
B. free coagulase.
C. extracellular coagulase.
D. catalase.- ✔✔✔A
A tube coagulase test was performed on catalase-positive, gram-positive cocci that were beta hemolytic
and grew on mannitol salt agar. The tube was checked after overnight incubation and was negative.
Which of the following statements explains this discrepancy?
A. A tube coagulase should not be performed on a catalase-positive organism.
B. A beta-hemolytic colony, which is catalase positive and grows on mannitol salt, is normally coagulase
negative.
C. The test should have been read in 1 to 4 hours in case any hemolysins are present.
D. No discrepancy is present; the results are accurate- ✔✔✔C
The tube coagulase test:
A. detects bound coagulase.
B. detects extracellular coagulase.
C. is performed on slide coagulase-positive isolates to confirm a positive result.
D. requires citrated reagent plasma- ✔✔✔B
In clinical isolates, the most likely identification of coagulase-positive, catalase-positive, gram-positive
cocci that are penicillin resistant would be:
A. Staphylococcus aureus.
,B. Staphylococcus intermedius.
C. Stomatococcus luteus.
D. Micrococcus aureus- ✔✔✔A
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?
A. Micrococcus luteus
B. Staphylococcus intermedius
C. Staphylococcus aureus
D. All Micrococcaceae- ✔✔✔C
The resident human flora, staphylococcus, which is more likely to cause infections in compromised hosts
such as patients with cancer, is:
A. S. saprophyticus.
B. S. aureus.
C. S. epidermidis.
D. S. intermedius- ✔✔✔C
The Staphylococcaceae staphylococcus that is more likely to cause uncomplicated urinary tract
infections in nonhospitalized hosts, especially sexually active young women, is:
A. S. saprophyticus.
B. S. aureus.
C. S. epidermidis.
D. S. intermedius.- ✔✔✔A
Isolates of coagulase-negative Staphylococcus from urinary tract infections can be presumptively
identified as S. saprophyticuson the basis of its:
, A. penicillin susceptibility.
B. novobiocin resistance.
C. penicillin resistance.
D. novobiocin susceptibility- ✔✔✔B
Quality control should be performed on which two organisms to determine the validity of the oxidase
reagent?
A. Staphylococcus aureus and S. epidermidis
B. S. epidermidis and Enterococcus
C. Aerococcus and Enterococcus
D. Micrococcus and Aerococcus- ✔✔✔D
An infected intravenous (IV) catheter tip grew out gram-positive cocci, which were catalase positive and
coagulase negative. The zone size of the novobiocin disk measured 18 mm. The most likely organism
causing infection is:
A. Staphylococcus saprophyticus.
B. S. epidermidis.
C. S. hominis.
D. S. cohnii- ✔✔✔B
Which organism is catalase positive, coagulase negative, pyrrolidonyl arylamidase (PYR) positive,
susceptible to novobiocin, urease negative, and beta hemolytic on sheep blood agar?
A. Staphylococcus epidermidis
B. S. saprophyticus
C. S. cohnii
D. S. haemolyticus- ✔✔✔D
1.
The most frequent agent of nosocomial bacteremia is:
A. catalase-negative micrococci.
B. coagulase-positive staphylococci.
C. catalase-negative stomatococci.
D. coagulase-negative staphylococci- ✔✔✔D
The species of Staphylococcus, which is one of the most important human pathogens, is:
A. S. lentus.
B. S. aureus.
C. S. mucilaginosus.
D. S. intermedius- ✔✔✔B
Which group of bacteria is described as catalase positive and is gram-positive cocci that grow
facultatively anaerobic and form grapelike clusters?
A. Neisseria
B. Rothia (stomatococci)
C. Staphylococcus
D. Micrococcus- ✔✔✔C
The first identification test performed on a clinical isolate of gram-positive, catalase-positive cocci would
likely be the:
A. penicillin test.
B. Gram stain.
,C. oxidase test.
D. coagulase test- ✔✔✔D
The slide coagulase test is a rapid screening test for the production of:
A. clumping factor.
B. free coagulase.
C. extracellular coagulase.
D. catalase.- ✔✔✔A
A tube coagulase test was performed on catalase-positive, gram-positive cocci that were beta hemolytic
and grew on mannitol salt agar. The tube was checked after overnight incubation and was negative.
Which of the following statements explains this discrepancy?
A. A tube coagulase should not be performed on a catalase-positive organism.
B. A beta-hemolytic colony, which is catalase positive and grows on mannitol salt, is normally coagulase
negative.
C. The test should have been read in 1 to 4 hours in case any hemolysins are present.
D. No discrepancy is present; the results are accurate- ✔✔✔C
The tube coagulase test:
A. detects bound coagulase.
B. detects extracellular coagulase.
C. is performed on slide coagulase-positive isolates to confirm a positive result.
D. requires citrated reagent plasma- ✔✔✔B
In clinical isolates, the most likely identification of coagulase-positive, catalase-positive, gram-positive
cocci that are penicillin resistant would be:
A. Staphylococcus aureus.
,B. Staphylococcus intermedius.
C. Stomatococcus luteus.
D. Micrococcus aureus- ✔✔✔A
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?
A. Micrococcus luteus
B. Staphylococcus intermedius
C. Staphylococcus aureus
D. All Micrococcaceae- ✔✔✔C
The resident human flora, staphylococcus, which is more likely to cause infections in compromised hosts
such as patients with cancer, is:
A. S. saprophyticus.
B. S. aureus.
C. S. epidermidis.
D. S. intermedius- ✔✔✔C
The Staphylococcaceae staphylococcus that is more likely to cause uncomplicated urinary tract
infections in nonhospitalized hosts, especially sexually active young women, is:
A. S. saprophyticus.
B. S. aureus.
C. S. epidermidis.
D. S. intermedius.- ✔✔✔A
Isolates of coagulase-negative Staphylococcus from urinary tract infections can be presumptively
identified as S. saprophyticuson the basis of its:
, A. penicillin susceptibility.
B. novobiocin resistance.
C. penicillin resistance.
D. novobiocin susceptibility- ✔✔✔B
Quality control should be performed on which two organisms to determine the validity of the oxidase
reagent?
A. Staphylococcus aureus and S. epidermidis
B. S. epidermidis and Enterococcus
C. Aerococcus and Enterococcus
D. Micrococcus and Aerococcus- ✔✔✔D
An infected intravenous (IV) catheter tip grew out gram-positive cocci, which were catalase positive and
coagulase negative. The zone size of the novobiocin disk measured 18 mm. The most likely organism
causing infection is:
A. Staphylococcus saprophyticus.
B. S. epidermidis.
C. S. hominis.
D. S. cohnii- ✔✔✔B
Which organism is catalase positive, coagulase negative, pyrrolidonyl arylamidase (PYR) positive,
susceptible to novobiocin, urease negative, and beta hemolytic on sheep blood agar?
A. Staphylococcus epidermidis
B. S. saprophyticus
C. S. cohnii
D. S. haemolyticus- ✔✔✔D
