Synonyms: Methicillin-resistant Staphylococcus Aureus

Medical Specialties: Dermatology, Family practice, Internal medicine

Clinical Definition

MRSA, or methicillin-resistant Staphylococcus Aureus, is a staph bacterium and the cause of certain skin infections in the community and serious hospital-acquired infections as well. S. aureus is common on the skin and in the nose and may be resistant to beta-lactam antibiotics (e.g., methicillin). Serious MRSA infections occur most frequently among patients in hospital settings.

In Our Own Words

Staphylococcus Aureus, or S. aureus for short, is a staph bacteria commonly found on the skin and in the nose and is a common cause of skin infections. While many people carry staph bacteria, only a small minority of carriers has MRSA, or methicillin-resistant Staphylococcus Aureus. More severe or life-threatening MRSA infections are most likely among patients in hospitals and other health care settings. MRSA infections also occur in sports settings, as the bacteria is spread by towels, uniforms, other clothing and sports equipment that had contact with a wound infected with the bacteria.


Symptoms vary, but can include redness of the skin, swelling and tenderness, depending on the part of the body infected. Self-care is not recommended if an MRSA infection is suspected, as the infection could worsen or spread to others. Medical attention is needed to obtain treatment, which may include antibiotics intravenously (i.e., infusing substances directly into a vein) and incision and drainage when needed.

Relevant Conditions
Common Types
  • Hospital-acquired
  • Community-acquired
Side Effects
  • Skin redness
  • Swelling of the skin
  • Tender skin
Share this article
  • Centers for Disease Control and Prevention. "Methicillin-resistant Staphylococcus aureus (MRSA) Infections.” Accessed September 2013.
  • Cleveland Clinic. "Preventing Skin Infection.” Accessed September 2013.
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