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Which group of bacteria is described as catalase positive and is gram-positive cocci that grow facultatively anaerobic and form grapelike clusters?
Staphylococcus
The first identification test performed on a clinical isolate of gram-positive, catalase-positive cocci would likely be the:
Latex or Coagulase test
The most frequent agent of nosocomial bacteremia is:
coagulase-negative staphylococci like S. epidermidis.
The species of Staphylococcus, which is one of the most important human pathogens, is:
Staphylococcus aureus.
The slide coagulase test is a rapid screening test for the production of:
clumping factor
The tube coagulase test:
detects extracellular coagulase.
Micrococcaceae is generally normal microbiota of the skin and should:
potentially be considered opportunistic pathogens in foreign body related infections.
An MLT is running a series of tests on patient specimens. On a 5% blood agar plate, the MLS observes small yellow colonies that are non-hemolytic. The direct gram stain shows gram positive cocci in tetrads. The MLT concludes that this organism is likely:
Micrococcus spp.
A tube coagulase test was performed on catalase-positive, gram-positive cocci that were β-hemolytic. The tube was checked after overnight incubation and was negative. Which of the following statements explains this discrepancy?
The test should have been read in 1 to 4 hours in case any hemolysins are present.
The staphylococci that is more likely to cause uncomplicated urinary tract infections in nonhospitalized hosts, especially sexually active young women, is:
S. saprophyticus.
The resident human microbiota, staphylococcus, which is more likely to cause infections in compromised hosts such as patients with cancer, is:
S. epidermidis.
In clinical isolates, the most likely identification of coagulase-positive, catalase-positive, gram-positive cocci that are penicillin resistant would be:
S. aureus.
A catalase positive organism with a yellowish pigment grew on 5% blood agar. The gram stain indicated gram positive clusters of cocci. Upon examining the patient history, it was discovered the specimen was from a child with pustules on the face appearing as impetigo. Based on this data, what is the likely organism?
Staphylococcus spp.
If a MRSA is identified in a patient's blood culture using a nucleic acid amplification test (NAAT), should you also culture the organism?
Yes - cultures are still required to confirm the identification AND to use for antibiotic sensitivity testing.
A newborn presented with a skin lesion that grew predominantly beta hemolytic colonies of 5% sheep blood agar. The gram stain revealed gram positive cocci. The newborn was covered with tiny “blister like” eruptions that resembled a burn. The isolate was catalase positive. Which test might the MLT conduct to confirm their suspicion?
Latex
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?
S. aureus
Isolates of coagulase-negative Staphylococcus from urinary tract infections can be presumptively identified as S. saprophyticus on the basis of its:
novobiocin resistance.
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 (susceptible, sensitive). The most likely organism causing infection is:
S. epidermidis.
Various molecular platforms exist for the detection of the mecA, methicillin resistant gene. Why is it necessary for these platforms to also detect species specific genes in addition to the mecA gene?
The platforms generally detect an additional sequence for species identification because the mecA gene is not confined to a single species
Which organism is catalase +, coagulase neg, susceptible to novobiocin, urease neg, and β-hemolytic on sheep blood agar?
S. haemolyticus