National Surveillance of Methicillin-resistant Staphylococcus aureus Among Hospitalized Pediatric Patients in Canadian Acute Care Facilities, 1995–2007

BACKGROUND: Information relating to the epidemiology of methicillin-resistant Staphylococcus aureus (MRSA) among hospitalized pediatric patients is limited. This report describes results of national MRSA surveillance among Canadian hospitalized pediatric patients from 1995 to 2007. METHODS: Surveillance was laboratory-based. Clinical and epidemiologic data were obtained by reviewing the medical records. Standardized definitions were used to determine MRSA infection. Isolates were characterized by pulsed-field gel electrophoresis, staphylococcal cassette chromosome mec typing and antimicrobial susceptibility testing. RESULTS: A total of 1262 pediatric patients were newly identified as MRSA positive from 1995 to 2007. Ages ranged from newborn to 17.9 years, 49% were infected with MRSA (51% colonized), skin and soft tissue infections accounted for the majority (59%) of MRSA infections and 57% were epidemiologically classified as community acquired (CA). The most common epidemic strain types isolated were CMRSA2/USA100/800, CMRSA10/USA300 and CMRSA7/USA400. Overall, MRSA rates per 10,000 patient days increased from 0.08 to 3.88. Since 2005, overall rates of CA-MRSA per 10,000 patient days have dramatically increased while healthcare-associated MRSA rates remained relatively stable. CONCLUSIONS: These data suggest that the increase in MRSA among hospitalized pediatric patients is largely driven by the emergence of CA-MRSA strains with skin and soft tissue infections representing the majority of MRSA infections.