Emergence of Community-Associated Methicillin-Resistant Staphylococcus aureus at a Memphis, Tennessee Children??s Hospital

Abstract
An epidemiologic investigation was performed because of a perceived increase in infections caused by community-associated methicillin-resistant Staphylococcus aureus (MRSA) among children in the greater Memphis area. We reviewed medical records of 289 children evaluated from January 2000 to June 2002 at a children's hospital. Clinical criteria were applied to classify MRSA isolates as community-associated (n=51) or health care-associated (n=138). The relatedness of 33 archived S. aureus isolates was evaluated using pulsed field gel electrophoresis (PFGE) of Sma I-digested genomic DNA; a common pulsed field type was defined as ≥80% similarity based on Dice coefficients. PFGE profiles were compared with those in a national database of MRSA isolates. During the first 18 study months, 46 of 122 MRSA isolates (38%) were community-associated; this proportion increased to 106 of 167 isolates (63%) during the last 12 study months (P mec Community-associated MRSA has emerged as a potentially invasive pathogen among children in the greater Memphis area, and this phenomenon is not explained by spread of nosocomial strains into the community.