What is Staphylococcus aureus?
Staphylococcus aureus, often referred to simply as "staph," are bacteria commonly carried on the skin or in the nose of healthy people. Occasionally, staph can cause an infection; staph bacteria are one of the most common causes of skin infections in the United States. Most of these infections are minor (such as pimples and boils) and most can be treated without antibiotics (also known as antimicrobials or antibacterials). However, staph bacteria can also cause serious infections (such as surgical wound infections and pneumonia). In the past, most serious staph bacteria infections were treated with a certain type of antibiotic related to penicillin. Over the past 50 years, treatment of these infections has become more difficult because staph bacteria have become resistant to various antibiotics, including the commonly used penicillin-related antibiotics (1). These resistant bacteria are called methicillin-resistant Staphylococcus aureus, or MRSA.
Where are staph and MRSA found?
Staph bacteria and MRSA can be found on the skin and in the nose of some people without causing illness.
How common is staph and MRSA?
Staph bacteria are one of the most common causes of skin infection in the United States, and are a common cause of pneumonia and bloodstream infections. Staph and MRSA infections are not routinely reported to public health authorities, so a precise number is not known. According to some estimates, as many as 100,000 persons are hospitalized each year with MRSA infections, although only a small proportion of these persons have disease onset occurring in the community. Approximately 25 to 30% of the population is colonized in the nose with staph bacteria at a given time (2). The numbers who are colonized with MRSA at any one time is not known. CDC is currently collaborating with state and local health departments to improve surveillance for MRSA. Active, population-based surveillance in selected regions of the United States is ongoing and will help characterize the scope and risk factors for MRSA in the community.
Are staph and MRSA infections treatable?
Yes. Most staph bacteria and MRSA are susceptible to several antibiotics. Furthermore, most staph skin infections can be treated without antibiotics by draining the sore. However, if antibiotics are prescribed, patients should complete the full course and call their doctors if the infection does not get better. Patients who are only colonized with staph bacteria or MRSA usually do not need treatment.
How are staph and MRSA spread?
Staph bacteria and MRSA can spread among people having close contact with infected people. MRSA is almost always spread by direct physical contact, and not through the air. Spread may also occur through indirect contact by touching objects (i.e., towels, sheets, wound dressings, clothes, workout areas, sports equipment) contaminated by the infected skin of a person with MRSA or staph bacteria.
How can I prevent staph or MRSA infections?
Practice good hygiene: