Gram-Positive Cocci in Clusters
This enzyme differentiates Staphylococcus from Streptococcus.
What is catalase?
The hemolysis pattern is the most commonly associated with Streptococcus pyogenes.
What is beta-hemolysis?
This GPR is spore-forming and commonly found in soil.
What is Bacillus species?
This medium is selective and differential for Staphylococci species.
What is mannitol salt agar (MSA)?
This enzyme forms a fibrin clot in blood plasma.
What is coagulase?
A catalase-positive, coagulase-positive organism is most consistent with this species.
What is Staphylococcus aureus?
This test differentiates Enterococcus from non-enterococcal streptococci
What is bile esculin?
This organism demonstrates tumbling motility at room temperature.
What is Listeria monocytogenes?
This medium enhances metachromic granules in Corynebacterium diphtheriae.
What is Loeffler medium?
This biochemical test differentiates catalase-negative streptococci that can survive in oxygen from strict anerobes.
What is peroxidase?
A coagulase-negative, novobiocin-resistant organism is most consistent with this species.
What is Staphylococcus saprophyticus?
This organism is PYR-positive and bacitracin-susceptible.
What is Streptococcus pyogenes?
This GPR is catalase-positive, non-spore-forming, and part of normal skin flora.
What is Corynebacterium species?
Black colonies with brown halos on this medium indicate tellurite reduction.
What is Tinsdale agar?
A positive result on this test explains survival in high-salt environments.
What is catalase?
This virulence factor allows S. aureus to evade opsonization.
What is Protein A?
This organism is alpha-hemolytic, optochin-sensitive, and bile soluble.
What is Streptococcus pneumoniae?
This organism forms spores and exhibits a “Medusa head” colony morphology.
What is Bacillus anthracis
This test demonstrates enhanced hemolysis when S. agalactiae is streaked near S. aureus.
What is the CAMP test?
This enzyme protects organisms from oxidative damage by converting superoxide radicals.
What is superoxide dismutase?
A blood culture from a patient with a prosthetic heart valve grows gram-positive cocci in clusters. The organism is catalase-positive, coagulase-negative, and novobiocin-susceptible. What is the most likely organism?
What is Staphylococcus epidermidis?
A wound culture grows beta-hemolytic gram-positive cocci in chains. The organism is PYR-negative and bacitracin-resistant.
What is Streptococcus agalactiae?
A pregnant patient presents with flu-like symptoms. Blood culture grows a gram-positive rod that is catalase-positive, beta-hemolytic, non-spore-forming, and demonstrates tumbling motility at room temperature. What is the most likely organisms?
What is Listeria monocytogenes?
A throat culture is submitted for suspected streptococcal infection. The lab technician uses a non-enriched medium and is unable to determine hemolysis patterns. What medium should have been used?
What is blood agar?
A bacterium retains crystal violet-iodine complex after alcohol decolorization. What biochemical property explains this?
Thick peptidoglycan layer with extensive cross-linking