Impact of a multi-disciplinary antimicrobial stewardship programme on piperacillin-tazobactam use at a Danish...

Piperacillin-tazobactam (TZP) is widely used empirically in Danish hospitals despite guideline restrictions, making it an important target for antimicrobial stewardship (AMS).

The aim of this study was to evaluate the impact of a multi-disciplinary AMS programme on TZP use, prescribing quality and clinical safety outcomes at a Danish university hospital.

A prospective, quasi-experimental study using interrupted time series (ITS) and two hospital-wide point prevalence surveys (PPS; 2021 and 2023) was conducted from January 2022 to December 2024. The AMS programme, introduced in January 2023, included prospective audit and feedback, education and monthly department-level reports. Days of therapy (DOT)/1,000 bed-days assessed antimicrobial trends. Logistic regression analysed guideline adherence and prescribing quality indicators; Poisson regression assessed changes in proportional DOT.

Among 156,035 admissions, 92,346 (59.2%) occurred in AMS-implementing departments. TZP use decreased by 19.5% (95% confidence interval [CI]: -25.5 to -13.5%; P < 0.001) but increased by 26.7% in non-AMS departments (95% CI: 18.6-34.9%; P < 0.001). Benzylpenicillin, ampicillin and aminoglycoside use increased by 14.2%, 20.2% and 36.4%, respectively, in AMS wards. PPS findings (N = 262) showed improved guideline adherence (odds ratio [OR]: 2.32, 95% CI: 1.38-3.90), documentation of indication (OR: 3.06), treatment planning (OR: 9.83) and reassessment within 72 h (OR: 2.52). Thirty-day readmission decreased from 11.6% to 10.2% (P = 0.0001), while in-hospital mortality remained unchanged (6.0% vs 6.1%; P = 0.962).

A multi-disciplinary AMS programme was associated with reduced TZP use and improved prescribing quality in participating departments without adverse effects on safety indicators. These findings support AMS as an effective strategy to optimise antibiotic use.