Impact of Antimicrobial stewardship implementation in an Intensive Care Unit in Central India – A Microbiologist-Intensivist driven initiative

Purpose This study evaluates a microbiologist–intensivist-driven prospective audit-feedback model in a 13-bedded tertiary-care critical care unit in Central India, using interrupted time-series analysis (ITS) to assess its impact on antimicrobial consumption (AMC), alongside diagnostic stewardship and patient outcomes. Methods This quasi-experimental study included both retrospective and prospective data collected over 20 months, divided into a 3-month pre-intervention phase (PIP), 12-month intervention phase (IP), and 5-month follow-up phase (FUP). Patients receiving targeted antimicrobials for more than 48 hours were included. Baseline AMC was recorded during PIP. During the IP, bi-weekly AMSP rounds with real-time recommendations on antimicrobial therapy, sample collection, and infection control practices were conducted. Culture reports, relevant laboratory parameters (leucocyte count, procalcitonin, invasive fungal markers), and clinical status (fever, vasopressor requirement, SOFA score) were reviewed to assess the appropriateness of therapy. AMC was measured as days of therapy/1000 patient-days and ITS analysis was done. Result A total of 398 patients were enrolled (PIP: 83; IP: 315). Cumulative average AMC significantly decreased from 2019.1 (PIP) to 1659.5 (IP) and was sustained during FUP (1635.2) even though ITS analysis revealed non-significant improvement. Use of reserve antimicrobials, including colistin/polymyxin, linezolid, and ceftazidime–avibactam–aztreonam, declined during IP. The mean number of antibiotics per patient decreased from 4.0 to 3.3, while ICU stay showed a numerical reduction from 13.5 to 10.7 days, although this difference was not statistically significant (P = 0.09). Mean SOFA across PIP (5.8) and IP (5.9) was similar. Urine, endotracheal and blood culture sampling declined significantly, reflecting more judicious, clinically guided testing. Conclusion A microbiologist–intensivist-driven AMSP is feasible and may reduce AMC in Indian ICU where infectious disease specialists are scarce. Integrating microbiology expertise with bedside decision-making offers a practical and scalable stewardship model for high-burden Lower Middle-Income Countries, and a scalable template for programme expansion.