ABOUT MRSA
Community-Associated MRSA
Information for the Public
The Centers for Disease Control and Prevention (CDC) has received inquiries about infections with antibiotic-resistant Staphylococcus aureus (including methicillin-resistant S. aureus [MRSA]) among persons who have no apparent contact with the healthcare system. The information below, released on February 3, 2005, addresses some of the most frequently asked questions.
What is MRSA?
What is Staphylococcus aureus (staph)?
Staphylococcus aureus, often referred to simply as “staph,” are bacteria commonly carried on the skin or in the nose of healthy people. Approximately 25% to 30% of the population is colonized (when bacteria are present, but not causing an infection) in the nose with staph bacteria. Sometimes, staph can cause an infection. Staph bacteria are one of the most common causes of skin infections in the United States. Most of these skin infections are minor (such as pimples and boils) and can be treated without antibiotics (also known as antimicrobials or antibacterials). However, staph bacteria also can cause serious infections (such as surgical wound infections, bloodstream infections, and pneumonia).
What is methicillin-resistant Staphylococcus aureus (MRSA)?
Some staph bacteria are resistant to antibiotics. MRSA is a type of staph that is resistant to antibiotics called beta-lactams. Beta-lactam antibiotics include methicillin and other more common antibiotics such as oxacillin, penicillin and amoxicillin. While 25% to 30% of the population is colonized with staph, approximately 1% is colonized with MRSA.
What is community-associated MRSA (CA-MRSA)?
Staph and MRSA can also cause illness in persons outside of hospitals and healthcare facilities. MRSA infections that are acquired by persons who have not been recently (within the past year) hospitalized or had a medical procedure (such as dialysis, surgery, catheters) are know as CA-MRSA infections. Staph or MRSA infections in the community are usually manifested as skin infections, such as pimples and boils, and occur in otherwise healthy people.
What does a staph or MRSA infection look like?
Staph bacteria, including MRSA, can cause skin infections that may look like a pimple or boil and can be red, swollen, painful, or have pus or other drainage. More serious infections may cause pneumonia, bloodstream infections, or surgical wound infections.