Micro & Immunology · single question
Impetigo is most commonly caused by which organism?
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Correct answer: B. Streptococcus beta-hemolytic
- A. Incorrect. S. epidermidis is a commensal skin organism and an uncommon cause of impetigo.
- B. CORRECT. Impetigo is primarily caused by Streptococcus pyogenes (Group A beta-hemolytic streptococcus) and/or Staphylococcus aureus. Beta-hemolytic streptococcus (particularly Group A) is the classic causative agent of bullous and non-bullous impetigo.
- C. Incorrect. Pseudomonas aeruginosa causes ear infections and wound infections in immunocompromised patients, not typical impetigo.
- D. Incorrect. Candida causes fungal infections — impetigo is a bacterial superficial skin infection.
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