Staphylococcus aureus Bacteremia in Children Aged 5-18 Years-Risk Factors in the New Millennium.

OBJECTIVES: To assess the association between comorbidities and Staphylococcus aureus bacteremia in children aged 5-18 years, thus, in children with a matured immune system. Further, we aimed to identify presumably healthy children acquiring bacteremia.

STUDY DESIGN: By cross-linking nationwide registries, we consecutively included all children born from 1995 onward at their 5-year birthday or date of immigration during 2000-2015. We examined incidence rate ratios (IRR) between preselected exposures and microbiologically verified S aureus bacteremia (reference = children without exposure) using Poisson regression models.

RESULTS: We followed 1 109 169 children in 2000-2015 during which 307 children (incidence rate: 3.7 per 100 000 person-years) acquired S aureus bacteremia (methicillin-resistant S aureus = 8; 2.6%). Children without known comorbidities or recent contact with the healthcare system comprised 37.1% of infected children. The highest IRRs were observed in children undergoing dialysis or plasmapheresis (IRR = 367.2 [95% CI) = 188.5-715.3]), children with organ transplantation (IRR = 149.5 [95% CI = 73.9-302.2]), and children with cancer (IRR = 102.9 [95% CI = 74.4-142.2]). Positive associations also were observed in children with chromosomal anomalies (IRR = 7.16 [95% CI = 2.96-17.34]), atopic dermatitis (IRR = 4.89 [95% CI = 3.11-7.69]), congenital heart disease (IRR = 3.14 [95% CI = 1.92-5.11]), and in children undergoing surgery (IRR = 3.34 [95% CI = 2.59-4.28]). Neither premature birth nor parental socioeconomic status was associated with increased disease rates.

CONCLUSIONS: S aureus bacteremia is uncommon in children between 5 and 18 years of age. Risk factors known from the adult population, such as dialysis, plasmapheresis, organ transplantation, and cancer, were associated with the highest relative rates. However, prematurity and parental socioeconomic status were not associated with increased rates. Approximately one-third of infected children were presumably healthy.