P-487. The Clinical and Microbiological Characteristics of Surgical Site and Bloodstream Infections in Children with Heart Disease Undergoing Cardiac Surgery: A Retrospective Single-Center Study

Abstract Background Postoperative infections in children with heart disease are associated with increased morbidity, mortality. Appropriate empirical antibiotic selection is critical for improving outcomes. This study aimed to characterize clinical and microbiological features of postoperative infections in this population. Methods This retrospective, single-center study included patients under 18years who underwent cardiac surgery or catheterization at Severance Hospital between January 1, 2020, and December 31, 2024. Isolates identified from the same type of culture more than 30 days apart were considered distinct. Primary outcome was the occurrence of microbiologically-proven bloodstream and surgical site infections (SSIs) within 30 days. Secondary outcome was to analyze the antimicrobial susceptibility. Results A total of 1,507 procedures were performed, comprising 778 therapeutic catheterizations (51.6%), 452 simple cardiac surgeries (30.0%), and 277 complex surgeries (18.4%). 48.0% of patients were male, with a median age of 1 year and 3 months (interquartile range [IQR], 1 month–6 years and 4 months). Among cardiac surgeries (n=729), bacteremia occurred in 31 cases (4.3%), fungemia in 6 (0.8%), and SSIs in 10 (1.4%). In the catheterization group (n =778), there were 13 cases of bacteremia (1.7%), 8 of fungemia (1.0%), and 9 SSIs (1.2%). The median time to diagnosis was 7 days (IQR, 2.5–18). Staphylococcus epidermidis (n = 9, 20.5%) was the most common bacterial pathogen, and Candida parapsilosis (n = 7, 50.0%) the most common fungal isolate. All-cause mortality among patients with bloodstream or surgical site infections was 25% (12/48). Antimicrobial susceptibility results are summarized in the table. Conclusion Bloodstream and surgical site infections following cardiac surgery in pediatric patients, though relatively infrequent, are associated with a high mortality rate of 25%. Notably, high methicillin and carbapenem resistance rates were observed. These findings emphasize the critical role of proper antibiotic use for improved patient outcome, guided by the antimicrobial stewardship program. Disclosures All Authors: No reported disclosures