MRSA infection

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MRSA infection

Definition:

MRSA infection is an infection with a strain of Staphylococcus aureus bacteria that is resistant to antibiotics known as beta-lactams. These antibiotics include methicillin, amoxicillin, and penicillin.

Alternative Names:

Methicillin-resistant Staphylococcus aureus; Community-acquired MRSA (CA-MRSA); Hospital-acquired MRSA (HA-MRSA)

Causes, incidence, and risk factors:

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Staphylococcus aureus (?staph?) are common bacteria that normally live on the skin. The bacteria also live harmlessly in the nasal passages ofroughly 30% of the U.S. population. Staph can cause infection when theyenterthe skin through a cut or sore. Infection can also occur when the bacteriamove inside of the body through a catheter or breathing tube. The infection can be minor and local (for example, a pimple), or more serious.

Most staph infections occur in people with weak immune systems, usually patients in hospitals and long-term care facilities. MRSA infections in hospitalized patients are known ashealthcare-associated MRSA (HA-MRSA). People who have been hospitalized or had surgery within the past year are at high risk for HA-MRSA. People receiving certain treatments, such as dialysis, are also at high risk. MRSA bacteria account fora large percentageof hospital-acquired staph infections.

Over the past several years, MRSA infections in people not considered high-risk have increased. These infections, known as community-associated MRSA (CA-MRSA), occur in otherwise healthy people who have no history of hospitalization in the last year. Manysuch infections have occured among athletes who share equipment or personal items (such as towels or razors) and children in daycare facilities.

References:

Braunwald E, Fauci AS, Kasper DL, et al., eds. Hyponatremia. In Harrison's Principles of Internal Medicine. 15th ed. New York, NY: McGraw-Hill; 2001:896-99.

Centers for Disease Control and Prevention. CA-MRSA Information for Clinicians. Available at: http://www.cdc.gov/ncidod/dhqp/ar_mrsa_ca_clinician.html. Accessed October 27, 2005.

Centers for Disease Control and Prevention. Healthcare-associated MRSA (HA-MRSA). Available at: http://www.cdc.gov/ncidod/dhqp/ar_mrsa.html. Accessed October 27, 2005.

Canadian Center for Occupational Health and Safety. Methicillin-resistant Staphylococcus aureus. Available at: http://www.ccohs.ca/oshanswers/biol_hazards/methicillin.html. Accessed October 27, 2005.