Follow-up Blood Cultures in Children With Staphylococcus aureus Bacteremia

BACKGROUND: Staphylococcus aureus is a common pathogen seen in pediatric bloodstream infections. Currently, no evidence-based recommendations are used to guide decisions on the number of follow-up blood cultures (FUBCs) needed to demonstrate infection clearance. Unnecessary cultures increase the risk of false-positives, add to health care costs, and create additional trauma to children and their families. In this study, we examined risk factors for persistent S aureus bacteremia (SAB) and intermittent positive blood cultures (positive cultures obtained after a documented negative FUBC result) to determine the number of FUBCs needed to demonstrate infection clearance in children.

METHODS: Patients ≤18 years who were hospitalized with SAB at Texas Children’s Hospital in 2018 were reviewed. We assessed the impact of an infectious disease diagnosis (central line–associated bloodstream infection, osteomyelitis, soft tissue infection, endocarditis, etc) and medical comorbidities on bacteremia duration. Patients with intermittent positive blood cultures were studied to determine the characteristics of this group and overall frequency of reversion to positive cultures.

RESULTS: A total of 122 subjects met the inclusion criteria. The median duration of bacteremia was 1 day (interquartile range: 1–2 days). Only 19 patients (16%) had bacteremia lasting ≥3 days, all of whom had a diagnosis of central line–associated bloodstream infection, osteomyelitis, or endocarditis. Intermittent positive cultures occurred in 5% of patients, with positive cultures after 2 negative FUBC results seen in <1% of patients. Intermittent positive cultures were strongly associated with osteomyelitis and endocarditis.

CONCLUSIONS: On the basis of our sample of children with SAB, additional blood cultures to document sterility are not necessary after 2 FUBC results are negative in well-appearing patients.