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Public Health - Seattle & King County

Methicillin-resistant S. aureus (MRSA)

Staphylococcus aureus, often referred to simply as "staph," is a type of bacteria commonly carried on the skin or in the nose of healthy people. Staph bacteria are one of the most common causes of skin infections. MRSA refers to types of staph that are resistant to an antibiotic called methicillin and related antibiotics. This means that infections with the bacteria do not respond to some of the antibiotics that are commonly used against staph infections. While 25% to 30% of the population is colonized with staph (meaning that bacteria are present, but not causing an infection or symptoms), approximately 1% are colonized with MRSA. In some areas of the country, MRSA is the most common cause of skin and soft tissue infections seen in emergency departments. MRSA is transmitted most frequently by direct skin-to-skin contact or contact with shared items or surfaces that have come into contact with someone else's infection.  MRSA transmission can be prevented by simple measures such as hand hygiene and covering infections. It is generally not necessary to close schools because of a MRSA infection in a student.

To reduce the risk of getting and spreading MRSA, you should:

  • See your health care provider promptly for evaluation and treatment of any skin or soft tissue infection.
  • Cover open or draining wounds at all times with a clean bandage or clothing - contact with drainage from an infected wound greatly increases the chance of transmission. If you have an open infected wound that cannot be kept securely covered, avoid physical contact with others until the wound is healed.
  • Wash your hands frequently with warm water and soap. Soaps containing antibacterials are not recommended.
  • Avoid sharing towels, clothing, or other objects that have come into contact with an open or draining wound.
  • Clean and disinfect any object, equipment, or surface that has come into contact with an open or draining wound. Use detergent-based cleaners, freshly made diluted bleach solution (1 tablespoon household bleach in 1 quart cool water, which is a 1:100 dilution equivalent to 500-615 parts per million [ppm] of available chlorine) or an EPA-registered disinfectant that is effective at removing MRSA from the environment. Cleaners containing antibacterials are not recommended.
Resources for the general public

MRSA in the community:

MRSA in child care:

MRSA in schools and athletic facilities:

MRSA in the workplace:

Resources for health care providers

Health advisories and news:

Guidelines for diagnosis and treatment: