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.