MRSA strains emerged in the last two decades in the US and similarities to the evolution of penicillin resistant S. aureus were noted with colonization and infection in the hospital based setting noted first. Again, risk factors for MRSA colonization or infection in the hospital were noted to include prior antibiotic exposure, admission to an intensive care unit, surgery, and exposure to an MRSA-colonized patient. Emergence of CA-MRSA strains has been noted in the last decade having resistance to methicillin and erythromycin but susceptibility to clindamycin. These strains have challenged the practitioner’s approach to the treatment of common skin and soft tissue infections as well as the management of invasive disease. The importance of such strains was underscored by the 1999 report detailing the deaths of 4 US children with invasive MRSA infection, none of whom had identifiable MRSA risk factors. Pulsed field typing of the isolates confirmed that these community strains were distinct from nosocomial strains isolated from patients in local hospitals.