Comparison of standard care versus a biomarker algorithm to guide antibiotic stewardship in pediatric intensive care unit: a prospective observational cohort study with historical control (the BASIP study).

UNLABELLED: The purpose of this study is to evaluate the effectiveness and safety of an integrated antimicrobial stewardship approach in critically ill children with suspected infection admitted to a pediatric intensive care unit (PICU). The approach combined procalcitonin (PCT)-guided decision-making with serial clinical and microbiological assessment to reduce antibiotic duration. Secondary aims included evaluating additional biomarkers, such as pancreatic stone protein (PSP) and C-reactive protein (CRP) in the context of antibiotic de-escalation. This prospective observational cohort study with historical control was conducted in a tertiary PICU. PCT and pediatric Sequential Organ Failure Assessment (p-SOFA) scores were assessed at baseline, 48-72 h, and 5-7 days. Microbiological samples were obtained before initiation of empirical antibiotic therapy and repeated when clinically indicated. Antibiotic decisions were made through multidisciplinary reassessment and were based on predefined PCT thresholds integrated with microbiological findings and clinical status. PSP and CRP were measured. Fifty-three children were prospectively enrolled. Median days of therapy (DOT) were lower compared with the historical cohort (10 days [IQR 5-16] vs. 16 days [IQR 7-29]). No increase in short-term adverse outcomes was observed. Restart of intravenous antibiotics or PICU readmission within 7 days occurred in 7.1% of cases. PCT levels differed significantly between confirmed and nonconfirmed bacterial infections (p = 0.001) and were associated with decisions regarding antibiotic de-escalation or discontinuation. CRP and PSP did not demonstrate statistically significant discriminatory capacity. CONCLUSION: Implementation of a structured PCT-guided reassessment algorithm within an antimicrobial stewardship framework was feasible and associated with reduced antibiotic exposure without apparent safety concerns. WHAT IS KNOWN: • Antimicrobial stewardship programs (AMS) are essential to reduce unnecessary antibiotic use and prevent antimicrobial resistance, especially in pediatric intensive care settings. • Although procalcitonin (PCT) has been validated in adult studies to guide antibiotic discontinuation, its integration into pediatric clinical decision-making remains poorly explored. WHAT IS NEW: • This study evaluates a real-world implementation of a PCT-based reassessment algorithm in a tertiary PICU in critically ill children. • An integrated, biomarker-guided algorithm using procalcitonin, alongside clinical and microbiological evaluation was associated with reduced antibiotic exposure without short-term safety signals.