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Stepwise implementation of an antimicrobial stewardship program in an open medical intensive care unit: Evaluation of antibiotic utilization and clinical outcomes

Year: 2026

Type: article

Abstract: OBJECTIVES: Appropriate antibiotic use is crucial in intensive care units (ICUs) where patients are highly vulnerable to infection and antimicrobial resistance. This study evaluated the effect of a stepwise antimicrobial stewardship program (ASP) on antibiotic utilization and clinical outcomes in an open medical ICU. METHODS: The ASP was implemented in two sequential stages. From July 2023, infectious disease specialists reviewed electronic records three times weekly for patients receiving meropenem or imipenem and suggested recommendations (record-based ASP). From September 2024, physician assistants (PA) joined these rounds, extending stewardship to all antibiotic users (round-based ASP). Study periods were pre-ASP (June 2022-June 2023, Period 1), record-based ASP (August 2023-August 2024, Period 2), and round-based ASP (October 2024-June 2025, Period 3). Outcomes included antibiotic utilization (days of therapy [DOT] per 1000 patient-days), multidrug-resistant organism isolation, and ICU mortality. RESULTS: Total antibiotic use decreased from 1462.6 DOT/1000 patient-days in Period 1 to 1335.4 (Incidence rate ratio, IRR 0.91, 95% CI: 0.89-0.94) in Period 2 and 1088.5 (0.82, 95% CI: 0.79-0.85) in Period 3. Meropenem/imipenem use declined from 228.2 to 176.0 (0.77, 95% CI: 0.71-0.84) and 132.6 (0.75, 95% CI: 0.68-0.84), and antipseudomonal β-lactam use from 655.5 to 592.2 (0.90, 95% CI: 0.86-0.95) and 448.8 (0.76, 95% CI: 0.72-0.80). Acinetobacter baumannii isolation and patient mortality also decreased between Periods 2 and 3. CONCLUSION: Stepwise ASP implementation significantly reduced antibiotic consumption and multidrug-resistant organism isolation. PA-supported stewardship rounds were feasible and associated with improved outcomes in an open ICU setting.

Source: International Journal of Infectious Diseases

DOI: 10.1016/j.ijid.2026.108413