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

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.

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.

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).

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.