Community-associated methicillin-resistant Staphylococcus aureus strains in pediatric intensive care unit

Abstract

Virulent community-associated methicillin-resistant Staphylococcus-aureus (CA-MRSA) strains have spread rapidly in the United States. To characterize the degree to which CA-MRSA strains are imported into and transmitted in pediatric intensive care units (PICU), we performed a retrospective study of children admitted to The Johns Hopkins Hospital PICU, March 1, 2007-May 31, 2008. We found that 72 (6%) of 1,674 PICU patients were colonized with MRSA. MRSA-colonized patients were more likely to be younger (median age 3 years vs. 5 years; p = 0.02) and African American (p<0.001) and to have been hospitalized within 12 months (p<0.001) than were noncolonized patients. MRSA isolates from 66 (92%) colonized patients were fingerprinted; 40 (61%) were genotypically CA-MRSA strains. CA-MRSA strains were isolated from 50% of patients who became colonized with MRSA and caused the only hospital-acquired MRSA catheter-associated bloodstream infection in the cohort. Epidemic CA-MRSA strains are becoming endemic to PICUs, can be transmitted to hospitalized children, and can cause invasive hospital-acquired infections. Further appraisal of MRSA control is needed.

Figure

Dendrogram of methicillin-resistant Staphylococcus aureus strains that colonized children admitted to the pediatric intensive care unit, The Johns Hopkins Hospital, Baltimore, MD, USA, 2007–2008. Isolates were characterized by pulsed-field gel electrophoresis (PFGE). Not all strains within a PFGE type had identical patterns, but strains were considered related with <3 band differences; 66 isolates were analyzed. The number of isolates related to each PFGE type is listed. *Reference strains.