microbiology an introduction 12th edition test bank Related

Review microbiology an introduction 12th edition test bank related questions and content

A wound smear from a patient revealed Gram-positive cocci arranged in clusters. The culture was catalase-positive and coagulase-positive. What is the causative agent?

  • A. Staphylococcus aureus
  • B. Streptococcus pyogenes
  • C. Micrococcus luteus
  • D. Enterococcus faecalis
Correct Answer: A

Rationale: The correct answer is A: Staphylococcus aureus.
1. Gram-positive cocci in clusters suggest staphylococci.
2. Catalase-positive indicates staphylococci since streptococci are catalase-negative.
3. Coagulase-positive further confirms Staphylococcus aureus, distinguishing it from other staphylococci.
Summary: B is incorrect as Streptococcus pyogenes is catalase-negative. C is incorrect as Micrococcus luteus is catalase-negative and coagulase-negative. D is incorrect as Enterococcus faecalis is catalase-negative and coagulase-negative.