Early Transition to Oral Antimicrobial Therapy among Children with Staphylococcus aureus Bacteremia and Acute Hematogenous Osteomyelitis

Background: Staphylococcus aureus bacteremia (SAB) is a frequent complication of acute hematogenous osteomyelitis (AHO) in children, but data on the optimal duration of parenteral antibiotics prior to transition to oral antibiotics remains sparse. We examined clinical outcomes associated with early transition to oral antimicrobial therapy among children admitted to our institution with AHO and SAB, and evaluated the utility of a severity of illness score (SIS) to guide treatment decisions in this setting. Methods: Children with AHO and SAB admitted to our institution between January 1, 2009, and December 31, 2018, were retrospectively reviewed and stratified according to a previously validated SIS into mild (0-3), moderate (4-7) and severe (8-10) cohorts. Groups were assessed for differences in treatment (eg, parenteral and oral antibiotic durations, surgeries) and clinical response (eg, bacteremia duration, acute kidney injury, length of stay and treatment failure). Results: Among 246 children identified with AHO and SAB, median parenteral antibiotic duration differed significantly between mild (n = 80), moderate (n = 98) and severe (n = 68) cohorts (3.6 vs. 6.5 vs. 14.3 days; P ≤ 0.001). SIS cohorts also differed with regard to number of surgeries (0.4 vs. 1.0 vs. 2.1; P ≤ 0.001), duration of bacteremia (1.0 vs. 2.0 vs. 4.0 days; P ≤ 0.001), acute kidney injury (0.0% vs. 3.0% vs. 20.5%; P ≤ 0.001), hospital length of stay (4.8 vs. 7.4 vs. 16.4 days; P ≤ 0.001) and total duration of antibiotics (34.5 vs. 44.7 vs. 60.7 days; P ≤ 0.001). Early transition to oral antimicrobial therapy among mild or moderate SIS cohorts was not associated with treatment failure despite SAB. Conclusions: SAB is associated with a wide range of illness among children with AHO, and classification of severity may be useful for guiding treatment decisions. Early transition to oral antimicrobial therapy appears safe in children with mild or moderate AHO despite the presence of SAB.