MRSA Infection and Contact Precautions

Methicillin-resistant Staphylococcus aureus (MRSA) is S. aureus that has reduced susceptibility to the beta-lactam class of antibiotics, which includes cloxacillin and the cephalosporins used for methicillin-sensitive S. aureus (MSSA). Resistance narrows the antibiotic choices. It does not make the organism more likely to cause infection or more severe infection. Infection with MRSA is still linked to a higher case-fatality rate than MSSA, most likely because effective therapy is often started later. S. aureus lives on the skin and mucous membranes of 60% or more of healthy adults, and about 10% to 20% of people carry it persistently. Colonization is carriage without tissue injury, and a colonized person usually looks well. Infection means the organism has invaded tissue. In a wound, look for increasing pain, redness, warmth, swelling, purulent drainage or delayed healing. Fever, chills, malaise or a rising heart rate point to a systemic response. MRSA can cause skin infections such as impetigo, furuncles, carbuncles and abscesses. It can also cause invasive disease such as bacteremia (septicemia), pneumonia, osteomyelitis and endocarditis. A positive screening swab proves carriage. It does not...