Definition:

Methicillin-resistant Staphylococcus aureus (MRSA) is one of the major multidrug-resistant bacteria which have become endemic in the hospital environment, particularly in intensive care units (ICUs). Originally limited to the hospital setting, MRSA is a growing cause of infections in the community. Community-associated MRSA (CA-MRSA) strains are genetically different from MRSA strains originating in the hospital. Its increase in the community is of concern because CA-MRSA strains appear to be highly virulent, and colonization with CA-MRSA is often undetected in hospitalized patients, which can facilitate its potential for becoming resistant to multiple antibiotics. Health care-associated MRSA (HA-MRSA) is usually associated with pneumonia, urinary tract, blood stream, and surgical wound infections. In contrast, CA-MRSA strains are overwhelmingly associated with skin and soft tissue infections.