Staphylococcus aureus (or S. aureus) also called staph, are bacteria commonly found on human skin; common places include inside the nose, in the armpit, groin, and genital area.
When bacteria are found on the skin but do not cause illness it is called "colonization." When the bacteria do cause illness the person is said to be "infected" with staph.
In most cases, staph either do not cause any problems or cause minor infections, such as pimples or boils. In some cases, staph can cause more serious infections.
Some staph bacteria are resistant to certain antibiotics. Methicillin-resistant S. aureus (MRSA) are resistant to the antibiotic methicillin and related antibiotics. Other antibiotics can be used to treat MRSA, but treatment may be longer and/or more expensive.
People who are colonized with staph or MRSA usually do not have any symptoms. Staph skin infections often begin with an injury allowing the bacteria to enter the skin and develop into an infection. Staph infections are sometimes mistaken for spider bits. Symptoms include:
Staph infections including MRSA are spread by close contact with infected people. Staph can come off of infected skin onto the skin of another person during skin-to-skin contact. Staph can also come off of infected skin onto shared object and surfaces and get onto the skin of the person who uses the object or surface next. The wound drainage and pus is very infectious. Examples of shared objects that might spread staph include:
In other words, anything that could have touched the skin of a staph-infected person can carry the bacteria to the skin of another person.
MRSA infections are more common among persons who have the following risk factors:
MRSA can also cause illness in healthy people who have not been patients in hospitals.
A sample of the infected area (for wounds, usually taken with a swab) is used to grow (culture) the staph bacteria in the laboratory.
Tests are then done to determine which antibiotics are active for treating the infection.
A culture of infected skin is especially useful in recurrent, persistent, or severe infections and in cases of antibiotic failure.
Most MRSA infections can be treated successfully with proper wound and skin care and by using antibiotics active against MRSA. If antibiotics are needed, they can usually be given by mouth.
A procedure by a healthcare provider to drain pus from the infected area (called incision and drainage or "I & D") may be necessary.
Some MRSA infections can be difficult to treat and can progress to serious and possibly life-threatening infections. Serious MRSA infections may require intravenous (given through a vein) antibiotic treatment.
People who are colonized but not infected with MRSA do not usually need to be treated.
If you suspect that you might have a staph skin infection, consult your health care provider as soon as possible. Early treatment can help prevent the infection from getting worse. Be sure to follow closely all instructions from your health care provider and if prescribed antibiotics, take all of your pills, even when you start to feel better.
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Major portions of this article were reprinted from information provided by Public Health-Seattle & King County.
Authored by: Hall Health Center Primary Care Clinic staff, reprinted in part from Public Health-Seattle & King County
Reviewed by: Hall Health Center Primary Care Clinic staff (KC), February 2014