title: Invasive Staphylococcus aureus Infections in Children in Tropical Northern Australia.
abstract: BACKGROUND
  Despite a high burden of staphylococcal skin disease in children and high incidence of Staphylococcus aureus bacteremia in adult Indigenous populations in northern Australia, there are few studies describing incidence or clinical information of invasive S aureus (ISA) infections in children.
  
  
  METHODS
  We conducted a retrospective review for all cases of S aureus bacteremia and sterile site infections, for children under 15 years, in northern Australia over a 4-year period (2007-2010). Cases were categorized as neonatal (<28 days) and pediatric (≥28 days).
  
  
  RESULTS
  Forty-four cases (9 neonatal, 35 pediatric) were identified. The annual incidence of ISA was 27.9 cases per 100 000 population. Among pediatric cases, the annual incidence was significantly higher in the Indigenous (46.6) compared with the non-Indigenous (4.4) population (IRR: 10.6 [95% confidence interval, 3.8-41.4]). Pediatric infections were predominantly community-associated (86%). Clinical infection sites included osteoarticular (66%), pleuropulmonary (29%), and endocarditis (9%), and multifocal disease was common (20%). Eighty-three percent of pediatric cases presented with sepsis; 34% resulted in intensive care admission. Neonatal cases were all born prematurely; 89% were late-onset infections. Overall, 27% of infections were due to methicillin-resistant S aureus (MRSA). Compared with methicillin-sensitive S aureus (MSSA), there was no difference in severity or presentation in pediatric MRSA cases, but a higher proportion of MRSA cases were readmitted.
  
  
  CONCLUSIONS
  The annual incidence of ISA infection in this study is among the highest described, largely due to a disproportionate burden in Indigenous children. Infections are frequently severe and infection with MRSA is common. Children presenting with suspected ISA in this region should be treated empirically for MRSA.
authors.affiliation: Royal Darwin Hospital, Darwin, Australia; Centre for International Child Health, University of Melbourne, Australia;
authors.forename: Daniel
authors.initials: D
authors.lastname: Engelman
authors.affiliation: Royal Darwin Hospital, Darwin, Australia;
authors.forename: Alexandra
authors.initials: A
authors.lastname: Hofer
authors.affiliation: Royal Darwin Hospital, Darwin, Australia; Menzies School of Health Research, Darwin, Australia;
authors.forename: Joshua S
authors.initials: JS
authors.lastname: Davis
authors.affiliation: Menzies School of Health Research, Darwin, Australia; Telethon Institute for Child Health Research, University of Western Australia, Perth.
authors.forename: Jonathan R
authors.initials: JR
authors.lastname: Carapetis
authors.affiliation: Royal Darwin Hospital, Darwin, Australia;
authors.forename: Robert W
authors.initials: RW
authors.lastname: Baird
authors.affiliation: Menzies School of Health Research, Darwin, Australia;
authors.forename: Philip M
authors.initials: PM
authors.lastname: Giffard
authors.affiliation: Menzies School of Health Research, Darwin, Australia;
authors.forename: Deborah C
authors.initials: DC
authors.lastname: Holt
authors.affiliation: Royal Darwin Hospital, Darwin, Australia; Menzies School of Health Research, Darwin, Australia;
authors.forename: Steven Y C
authors.initials: SY
authors.lastname: Tong
keywords: Staphylococcus aureus.; bacteremia; indigenous; neonatal; pediatric