Empiric MRSA Coverage for Children with Osteoarticular Infections: 2015 to 2024.

BACKGROUND AND OBJECTIVES: Staphylococcus aureus is the most common causative pathogen for children with acute hematogenous osteomyelitis (AHO) and acute bacterial arthritis (ABA). National guidelines recommend empiric coverage for methicillin-resistant S. aureus (MRSA) at hospitals where the overall MRSA rate is greater than 10% to 20%. The objective of this study was to evaluate the frequency and appropriateness of empiric MRSA coverage for AHO and ABA among hospitalized children in the United States. METHODS: Hospital encounters from September 2015 through December 2024 for AHO and ABA were identified using the Pediatric Health Information System (PHIS) database and were categorized based on validated, pathogen-specific discharge codes. Hospital-specific rates of methicillin resistance among all S. aureus isolates were collected directly from participating PHIS hospital antibiograms. RESULTS: A total of 15 841 hospitalizations from 46 PHIS hospitals were included. Among the 48% of children with a pathogen-specific discharge code assigned, 17% were MRSA. Most children without MRSA identified (58%) received empiric MRSA antimicrobial therapy. Most hospital antibiograms had an MRSA rate above 20%, although the rate of MRSA for AHO and ABA was consistently less than hospital-wide MRSA rates. Across all PHIS hospitals, the MRSA rate for AHO and ABA was half that of hospital-wide MRSA rates (0.5; range, 0.2-1.17). CONCLUSIONS: Most children hospitalized in the United States for AHO and ABA receive empiric MRSA therapy, although few have MRSA identified. Hospital-wide antibiograms consistently have a higher MRSA rate than seen in patients with AHO and ABA, and development of AHO- and ABA-specific antibiograms may improve targeted empiric therapy for children with osteoarticular infections.