Pediatric Staphylococcus aureus Bacteremia: Clinical Spectrum and Predictors of Poor Outcome

Background Staphylococcus aureus is a common cause of bacteremia, yet the epidemiology and predictors of poor outcome remain inadequately defined in childhood. Methods ISAIAH (Invasive Staphylococcus aureus Infections and Hospitalizations in children) is a prospective, cross-sectional study of S. aureus bacteremia (SAB) in children hospitalized in Australia and New Zealand over 24 months (2017-2018). Results Overall, 552 SABs were identified (incidence 4.4/100 000/year). Indigenous children, those from lower socioeconomic areas and neonates were overrepresented. Although 90-day mortality was infrequent, one-third experienced the composite of: length of stay >30 days (26%), intensive care unit admission (20%), relapse (4%), or death (3%). Predictors of mortality included prematurity (adjusted odds ratio [aOR],16.8; 95% confidence interval [CI], 1.6-296.9), multifocal infection (aOR, 22.6; CI, 1.4-498.5), necrotizing pneumonia (aOR, 38.9; CI, 1.7-1754.6), multiorgan dysfunction (aOR, 26.5; CI, 4.1-268.8), and empiric vancomycin (aOR, 15.7; CI, 1.6-434.4); while infectious diseases (ID) consultation (aOR, 0.07; CI .004-.9) was protective. Neither MRSA nor vancomycin trough targets impacted survival; however, empiric vancomycin was associated with nephrotoxicity (OR, 3.1; 95% CI 1.3-8.1). Conclusions High SAB incidence was demonstrated and for the first time in a pediatric setting, necrotizing pneumonia and multifocal infection were predictors of mortality, while ID consultation was protective. The need to reevaluate pediatric vancomycin trough targets and limit unnecessary empiric vancomycin exposure to reduce poor outcomes and nephrotoxicity is highlighted. One in 3 children experienced considerable SAB morbidity; therefore, pediatric inclusion in future SAB comparator trials is paramount to improve outcomes. ISAIAH is a large, prospective, multicenter study of Staphylococcus aureus bacteremia (SAB) in children hospitalized in Australia and New Zealand over 24 months. A deeper understanding of SAB epidemiology, clinical phenotype, and pediatric-specific risk factors for poor outcome is provided.