COMMUNITY-ASSOCATED METHICILLIN RESISTANT STAPHYLOCOCCUS AUREUS IN THE LOS ANGELES COUNTY JAIL: A 4-YEAR REVIEW BACKGROUND Methicillin resistant Staphylococcus aureus

Methicillin resistant Staphylococcus aureus (MRSA) is well known as a nosocomial (healthcare acquired) pathogen. However, since the 1990s, MRSA has been increasingly recognized as a community pathogen. Community associated MRSA (CAMRSA) is distinguished from healthcare associated MRSA (HAMRSA) by clinical and molecular characteristics—HAMRSA is associated with invasive disease (pneumonia, bloodstream infections, surgical site infections) in older persons who have significant exposure to healthcare while CAMRSA causes mostly skin and soft tissue infections, which are often misdiagnosed as “spider bites.” CAMRSA tends to be sensitive to many oral antibiotics whereas HAMRSA, especially in intensive care units, may only be sensitive to intravenous antibiotics. CAMRSA is further distinguished from HAMRSA by the presence of genes for Panton-Valentine leukocidin (PVL), a potent toxin that causes tissue necrosis, and is associated with skin inflammation. Furthermore, CAMRSA and HAMRSA have distinctly different pulsed-field gel electrophoresis (PFGE) patterns, indicating that they derived from different strains of S. aureus.