Impact of a Hospital-Based Antibiotic Stewardship Intervention on Microbiome Diversity in Pediatric Inpatients

Background: Antibiotic overuse in hospitalized children disrupts the developing gut microbiome, potentially contributing to dysbiosis-related complications including secondary infections, immune dysregulation, and longterm metabolic consequences. Antibiotic stewardship programs have been widely implemented to optimize antimicrobial prescribing, yet their direct impact on gut microbiome diversity in pediatric inpatients remains poorly characterized. Methods: A prospective quasi-experimental study was conducted over 12 months involving 136 pediatric inpatients aged 1–14 years admitted to a tertiary care hospital. Patients were divided into a pre-intervention cohort (n = 68) receiving standard care and a post-intervention cohort (n = 68) managed under a structured antibiotic stewardship protocol. Stool samples were collected at admission and discharge for 16S rRNA gene sequencing. Shannon diversity index, observed operational taxonomic units, and Firmicutes-to-Bacteroidetes ratio were analyzed alongside antibiotic utilization data. Results: The stewardship intervention significantly reduced broad-spectrum antibiotic use by 31.4% (p < 0.001). At discharge, the post-intervention cohort demonstrated significantly higher Shannon diversity index (2.94 ± 0.51 vs. 2.38 ± 0.63; p = 0.001) and observed OTUs (187.3 ± 34.6 vs. 152.8 ± 41.2; p < 0.001) compared to the preintervention group. The decline in microbiome diversity from admission to discharge was significantly attenuated in stewardship-managed patients. Conclusion: Hospital-based antibiotic stewardship interventions effectively preserve gut microbiome diversity in pediatric inpatients while reducing unnecessary antimicrobial exposure, supporting their integration into pediatric hospital practice.