Impact of an antimicrobial stewardship-based infection prevention bundle on postoperative central nervous system infection in a tertiary neurosurgery department: a quasi-experimental study.

BACKGROUND: Antimicrobial stewardship integration into infection prevention bundles remains inadequately addressed in neurosurgery. AIM: To evaluate the impact of an antimicrobial stewardship-based infection prevention bundle on postoperative central nervous system infection (PCNSI) incidence, antibiotic use density (AUD), and consumption of vancomycin and meropenem. METHODS: A quasi-experimental before-and-after study compared 6-month periods before and after implementation. The bundle comprised perioperative optimization, infection control enhancements, surgical site and drainage management, microbiological stewardship, and antimicrobial stewardship components. RESULTS: A total of 1,535 patients were analyzed (782 pre-intervention period, 753 post-intervention period). Surgical case-mix shifted significantly, with increased neurotrauma (15.73%-23.37%) and decreased cerebrovascular (45.40%-39.84%) and CSF/hydrocephalus (6.14%-2.79%) procedures. Overall PCNSI incidence decreased from 2.81% to 1.86% [0.654 (95% CI: 0.332-1.289); P = 0.217]. Neurotrauma-specific PCNSI declined from 5.69% to 1.14% [0.190 (95% CI: 0.039-0.933); unadjusted P = 0.035], but it did not remain significant after correction for multiple comparisons. Monthly AUD decreased by 12.0% (P = 0.022). Vancomycin and meropenem consumption decreased by approximately 55% across all metrics (all P < 0.05), with large to very large effect sizes (Cohen's d = 1.561-2.604). CONCLUSION: The bundle was associated with significant reductions in special-use antimicrobial consumption, supporting practical implications for resistance mitigation and safety. The overall PCNSI decrease was not statistically significant. These findings are consistent with potential intervention benefit, pending validation in adequately powered prospective studies.