Beyond methicillin resistance: clinical outcomes of pediatric staphylococcus aureus infections in a tertiary care center

Background Staphylococcus aureus (S. aureus) is a major cause of pediatric infections. Whether methicillin resistance independently influences outcomes remains unclear, and local antimicrobial susceptibility data are essential for guiding empirical therapy. Methods We retrospectively analyzed hospitalized children with culture-confirmed S. aureus infections between January 2015 and June 2023. Clinical characteristics, treatments, outcomes, antimicrobial susceptibility patterns, and predictors of clinical response and infection-related mortality were evaluated. Results A total of 392 hospitalized patients were included (321 MSSA, 71 MRSA). Demographic characteristics and underlying diseases were similar between groups. MRSA infections were associated with higher pediatric intensive care unit admission rates (38.0% vs. 24.0%, p = 0.015), longer treatment duration (median 16 vs. 14 days, p = 0.011), and longer hospital stay (median 28 vs. 17 days, p = 0.002). Relapse, treatment response, and infection-related mortality (3.3%) were comparable between groups. In multivariable analysis, transfusion (OR 6.78, 95% CI 1.28–35.95) and inotrope support (OR 9.09, 95% CI 2.48–33.26), but not methicillin resistance, independently predicted infection-related mortality. All isolates were susceptible to vancomycin, teicoplanin, linezolid, and daptomycin. Clindamycin susceptibility was lower and more variable among MRSA isolates (range 33.3–100% across years) compared to MSSA (range 81.6–93.3%), whereas trimethoprim–sulfamethoxazole maintained consistently high activity in both groups. Conclusion Methicillin resistance was associated with greater clinical severity but not poorer outcomes. Infection-related mortality was driven by host and severity factors rather than resistance status alone. These findings support empirical treatment decisions based on local susceptibility patterns and emphasize the importance of addressing the overall burden of pediatric S. aureus infections.