Methicillin Resistant Staphylococcus Aureus (MRSA): Overview

Staphylococcus aureus is a common bacteria (germ) that is present on the skin and in the nose of many people. For most healthy people, this bacteria doesn't cause a problem, however, it can enter the body and cause infection. The bacteria is most likely to enter the body if:

• there is an open wound in the skin; or
• the person has a suppressed immune system.

Most types of s. aureus can be treated with antibiotics. Methicillin, which is like penicillin, is one antibiotic that is often used. Over time, some types of s. aureus have become resistant to methicillin. This means methicillin does not work to treat the infection, so another antibiotic needs to be used instead. Therefore, methicillin resistant s. aureus (MRSA) is more difficult to treat.

Colonization Versus Infection

Colonization means the MRSA is present in or on the body but is not causing illness. Healthy people may carry the bacteria causing MRSA without becoming ill. Infection means the MRSA is present in or on the body and is causing illness. Symptoms of MRSA may vary depending on the part of the body that is infected. Infection can commonly occur in the skin, but can also occur in any organ in the body.

MRSA is commonly spread by direct, hand-to-hand contact, and it can be contracted in the hospital or community setting.

This information has been approved by Gwen Huitt, MD, MS (May 2008).