# P-76. Age-Dependent Diagnostic Yield and Treatment in Pediatric Bone and Joint Infections

## TL;DR

This study examines how molecular testing improves diagnosis of pediatric bone and joint infections, especially in children under 5 years old.

## Contribution

The study evaluates the clinical value of PCR testing in diagnosing pediatric bone and joint infections across age groups.

## Key findings

- PCR testing increased organism identification in younger children (<5 years) from 37% to 54.3%.
- Amoxicillin/clavulanate was more frequently prescribed in younger children with negative cultures due to concerns about K. kingae.

## Abstract

Molecular testing of surgical specimens is recommended to increase the yield of bacterial identification in culture negative cases of pediatric bone and joint infections (BJI); particularly in pre-school aged patients < 5 years at risk for Kingella kingae. The clinical benefit of polymerase chain reaction (PCR) for BJI in children > 5 years, however, remains less clear. This study evaluates the diagnostic yield and added clinical value of PCR testing for BJI in patients < 5 and ≥5 years old at a tertiary pediatric center.Table 1.Diagnostic Yield of BJI via Culture and PCRTable 2.Isolated Organisms in BJI via Culture and PCR

Diagnostic Yield of BJI via Culture and PCR

Isolated Organisms in BJI via Culture and PCR

This single-center, multi-site, retrospective cohort study included pediatric patients admitted between January 2015 to April 2024 in Central Texas diagnosed with BJI. Cases were reviewed for demographics, diagnosis of BJI, antimicrobial treatment, results of blood, bone and synovial fluid cultures, results of PCR testing, and readmission related to BJI treatment failure. Cases were compared by age (< 5 years vs > 5 years) for bacterial identification and benefit of PCR testing. Oral antibiotics at discharge were assessed to determine if positive culture or molecular testing impacted antimicrobial choice.Figure 1.Oral Antibiotics at Discharge for BJIs

Oral Antibiotics at Discharge for BJIs

168 patients were included (81 patients < 5 years, 87 patients ≥5 years). Cultures were positive in 37% patients < 5 years and 62.1% patients ≥5 years. Molecular testing increased organism identification to 54.3% and 64.4%, respectively. Staphylococcus aureus and K. kingae were the most common pathogens identified. Amoxicillin/clavulanate or cephalexin was prescribed at discharge in a majority of patients regardless of organism identification. Amoxicillin/clavulanate was prescribed more often in patients < 5 years with negative cultures due to concern for K. kingae. One case with confirmed methicillin-susceptible S. aureus treated with cephalexin required readmission for treatment failure.

The incorporation of PCR significantly enhanced diagnostic yield in patients < 5 years with BJI, particularly through detection of K. kingae. However, regardless of pathogen identification, a majority of patients were discharged on either amoxicillin/clavulanate or cephalexin. Further research is warranted to assess the clinical benefit of PCR testing in pediatric BJI, where its impact on clinical outcomes remains uncertain.

All Authors: No reported disclosures