An Evaluation of a Syndromic Molecular Panel in Optimising the Microbiological Diagnosis and Antimicrobial Therapy of Suspected Osteoarticular Infections in Paediatric Patients.

Paediatric osteoarticular infections (POAIs) present unique diagnostic and therapeutic challenges. Microbiological culture (MC) is typically time-consuming and lacks sensitivity, especially when patients have received antibiotics. The BIOFIRE Joint Infection Panel (BJIP) is a syndromic molecular assay for the direct identification of most pathogens causing POAIs. We evaluated BJIP in 17 synovial fluids, and then, we retrospectively assessed its utility in 93 off-label specimens (i.e., 25 purulent fluids/biopsies and 68 whole blood samples). All specimens were collected from October 2022 to March 2024 from paediatric patients admitted at the Bambino Gesù Children's Hospital in Rome. A bacterial pathogen was isolated in only one of 17 synovial fluid cultures, while BJIP identified eight additional microorganisms in MC-negative cases. The most frequently detected pathogen was (44.5%, 4/9). BJIP performance in synovial fluids showed an overall positive percentage agreement (PPA) and negative percentage agreement (NPA) of 100% and 88.1%, respectively, compared to MC. All positive results (n/N = 9/17) were considered medically significant, with an increase in NPA to 100%. In purulent fluids/biopsies, BJIP and MC were concordant in 72% of cases (n/N = 18/25), with a per-sample PPA and NPA of 90% and 60%, respectively. For whole blood samples, almost all samples were negative by both methods (i.e., reference blood culture and BJIP), and the molecular test did not enable any further microbiological diagnosis. The BIOFIRE Joint Infection Panel rapidly and accurately enabled or excluded a diagnosis of a POAI (~1 vs. 24-96 h for MC), optimising antimicrobial therapy.