Impact of a Multifaceted Antimicrobial Stewardship Program on Antimicrobial Use and Prescription Quality in a Pediatric Intensive Care Unit: An Interrupted Time-Series Study

Background: Inappropriate antibiotic use contributes to antimicrobial resistance. Evidence regarding the impact of antimicrobial stewardship programs (ASPs) in pediatric intensive care units (PICUs) remains limited. The study aims to evaluate the impact of a multidisciplinary prospective post-prescription review and feedback (PPRF) ASP in a European PICU on antimicrobial use and prescription quality (PQ). Methods: A prospective quasi-experimental study was conducted using interrupted time-series analysis to evaluate antimicrobial use trends before (July 2018–December 2020) and after (January 2021–March 2025) the implementation of a multifaceted ASP, integrated within a hospital-wide ASP, in a tertiary 24-bed medical–surgical PICU in Barcelona, Spain. Antimicrobial use was measured as days of therapy per 100 patient-days (DOT/100 PD) and per 100 discharges (DOT/100 D) and was analyzed by WHO AWaRe group and by individual drug. PQ was evaluated by means of cross-sectional point-prevalence surveys (PPSs). Results: During the study-period, median monthly activity in the PICU remained stable: 475 patient-days (IQR: 396–534) and 113 patients discharged (IQR: 102–124). Following ASP implementation, total antibiotic consumption significantly decreased, with an immediate reduction of 18.2 DOT/100 patient-days (p = 0.006) and a sustained monthly decline of 0.73 DOT/100 patient-days (p = 0.028). The COVID-19 pandemic did not significantly affect overall antibiotic consumption. Access and Reserve antibiotic use decreased significantly after ASP implementation, whereas Watch antibiotic use remained unchanged. Overall antifungal consumption was not significantly modified, although a transient increase was observed during the pandemic. At the individual drug level, several antibiotics demonstrated significant immediate decreases after ASP implementation. Prescription quality remained high (>88% optimal prescriptions), and PICU length of stay and mortality were unchanged. Conclusions: Implementation of a multidisciplinary PPRF-based ASP in a tertiary PICU was associated with a sustained reduction in antibiotic exposure without compromising prescription quality or clinical safety. These data support the effectiveness of collaborative stewardship in one of the most complex pediatric healthcare settings.