Clinical impact of the BIOFIRE FILMARRAY Pneumonia Panel combined with antimicrobial stewardship education on pediatric patients with lower respiratory tract infection: a pre-post study from a tertiary center in Nara, Japan.

UNLABELLED: Lower respiratory tract infections (LRTIs) account for a large share of pediatric antimicrobial prescriptions. The BIOFIRE FILMARRAY Pneumonia Panel (FAPN; BioMérieux) detects 33 respiratory pathogens within approximately 1 h. We investigated the clinical impact of its systematic introduction-combined with antimicrobial stewardship education. A retrospective cohort study was conducted at a tertiary pediatric center in Japan, enrolling all children aged <18 years with a lower respiratory tract infection between April 2023 and April 2026. In the post-FAPN period (April 2025-April 2026), the FAPN was implemented, alongside structured stewardship education incorporating a clinical decision flowchart. Logistic regression and generalized linear model (GLM) regression with log-link negative binomial distribution were employed for categorical and quantitative outcomes, respectively. Interrupted time-series analysis (ITSA) was performed using bimesters as time units and Newey-West standard errors. A total of 815 children were enrolled (pre-FAPN: 590; post-FAPN: 225). Antimicrobial prescribing rates were significantly lower following FAPN implementation (adjusted odds ratio, aOR: 0.39; 95% CI: 0.28-0.55; P < 0.001). Adjusted GLM regression identified a significant reduction in broad-spectrum antibiotic DOTs (adjusted β: -0.41; 95% CI: -0.66 to -0.05; P = 0.001), while narrow-spectrum antibiotic DOTs were unchanged. ITSA also confirmed a significant reduction in antimicrobial prescription rate (β: -0.53; 95% CI: -0.84 to -0.21; P = 0.001). The FAPN, combined with structured stewardship education, was significantly associated with reduced antimicrobial prescribing and a shift away from broader-spectrum antimicrobials. These findings support the clinical value of rapid multiplex PCR diagnostics in pediatric LRTIs when integrated with a strong antimicrobial stewardship program. IMPORTANCE: A strong stewardship education program may need to be combined with the introduction of a multiplex PCR test for pediatric pneumonia. With a clear decision flowchart, clinicians could successfully reduce antimicrobial use and shift their antimicrobial prescriptions to narrower ones.