KROK 1 2008 – Question 33 · KROK (Medicine) · Microbiology, Virology, and Immunology
Examination of a patient with pustular skin lesions allowed to isolate a causative agent that forms in the blood agar roundish yellow middle-sized colonies surrounded by haemolysis zone. Smears from the colonies contain irregular-shaped clusters of gram-positive cocci. The culture is oxidase- and catalase-positive, ferments mannitol and synthesizes plasmocoagulase. What causative agent was isolated?
- A. Streptococcus pyogenes
- B. Streptococcus agalactiae
- C. Staphylococcus aureus
- D. Staphylococcus saprophyticus
- E. Staphylococcus epidermidis
Hint
Pay attention to plasmacoagulase and mannitol fermentation together with the cluster arrangement of the cocci; these separate the pathogenic species of the genus from its harmless relatives.
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