Staphylococcus aureus Bacteremia in Children: The Effect of Methicillin Resistance

BACKGROUND: Staphylococcus aureus bacteremia can occur in children in association with skin/soft tissue, musculoskeletal, respiratory, and endovascular infections. The effect of methicillin resistance on clinical outcomes in children with S. aureus bacteremia has not been clearly described. METHODS: Single center retrospective cohort study over a 5-year period of children ≤18 years hospitalized with monomicrobial S. aureus bacteremia at a tertiary care children’s hospital. We compared baseline characteristics and clinical outcomes between those with methicillin-sensitive S. aureus (MSSA) and methicillin-resistant S. aureus (MRSA) bacteremia using chi-squared test for dichotomous and t-test for continuous variables. We built a multivariable linear regression model to determine the effect of methicillin resistance on duration of bacteremia. RESULTS: We identified 334 episodes of S. aureus bacteremia, 233 (70%) with MSSA and 101 (30%) with MRSA. Mean age was 5.4 years; 42.6% were hospital onset infections (49.8% MSSA vs. 25.7% MRSA; P < 0.001); 68.4% (73.3% vs. 55.7%; P = 0.003) occurred in children with chronic medical conditions; and 31.5% occurred in black children (25.9% vs. 44.6%; P = 0.001). Primary site of infection was catheter-related in 31.7% (37.9% vs. 18.7%), musculoskeletal in 28.1% (25.3% vs. 34.1%); skin/soft tissue in 14.2% (13.2% vs. 16.5%); pneumonia in 6.4% (3.2% vs. 13.2%); and no source identified in 11.4% (13.7% vs. 6.6%). Eleven children (3.5%) died within 30 days of bacteremia onset (3.7% vs. 3.0%; P = 0.73), 8 (2.7%) had recurrence within 30 days (2.4% vs. 3.3%; P = 0.65), and 23.4% (18.1% vs. 35.6%; P = 0.001) developed complications including septic emboli or metastatic foci of infection. Duration of bacteremia was 2.2 days (1.8 vs. 3.0; P < 0.001). Adjusting for primary site of infection and performance of a surgical drainage procedure, methicillin resistance was associated with longer duration of bacteremia (+1.2 days; 95% CI: 0.71 to 1.66). CONCLUSION: In this cohort of children with S. aureus bacteremia, methicillin resistance was associated with community-onset infections, black race, increased risk for complications, and longer duration of bacteremia. DISCLOSURES: All authors: No reported disclosures.