Methicillin-resistant Staphylococcus aureus; Community-acquired MRSA (CA-MRSA); Hospital-acquired MRSA (HA-MRSA)
Methicillin-resistant Staphylococcus aureus (MRSA) is a type (strain) of staph bacteria that does not respond to some antibiotics that are commonly used to treat staph infections.
Staph. aureus is a common type of bacteria. In about 1 out of every 4 healthy people, the staph germ lives on the skin or in the nasal passages, but it does not cause any problems or infections. These people are said to be colonized with staph.
If the staph bacteria enter a person's body through a cut, sore, catheter, or breathing tube, it may cause an infection.
In the past, most staph infections responded to a gorup of antibiotics called beta-lactams. These antibiotics include methicillin and other, more common antibiotics such as oxacillin, penicillin, and amoxicillin.
About 2 out of every 100 people carry a strain of staph that is resistant to these antibiotics. Being resistant means an antibiotic is unable to treat and cure an infection with this type of bacteria.
This strain of staph is called MRSA, or methicillin-resistant Staphylococcus aureus. MRSA infections often occur in people who are in the hospital or other health care setting. Those who have been hospitalized or had surgery within the past year are also at increased risk. MRSA bacteria are causing a higher number of the staph infections that begin in the hospital.
MRSA infections that occur in the community are seen in otherwise healthy people who have not recently been in the hospital. Most of these infections involve the skin.
Centers for Disease Control and Prevention.
Que YA, Moreillon P. Staphylococcus aureus (including staphylococcal toxic shock). In: Mandell GL, Bennett JE, Dolin R, eds. Principles and Practice of Infectious Diseases. 7th ed. Philadelphia, Pa: Elsevier Churchill Livingstone; 2009:chap 195.
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