Targeted antimicrobial stewardship (AMS) is associated with improved prescribing quality and reduced broad-spectrum antibiotic use, according to a recent Danish study, supporting structured, multidisciplinary interventions.

The prospective, quasi-experimental before-and-after study evaluated the impact of a multidisciplinary AMS programme on piperacillin–tazobactam (TZP) use at Copenhagen University Hospital in Denmark.

Published in the Journal of Hospital Infection, the study aimed to reduce broad-spectrum antibiotic use, improve prescribing quality and assess clinical safety following AMS implementation.

Following a pilot phase from September to December 2022 in which baseline TZP prescribing was assessed, the intervention was introduced in January 2023 and included prospective audit and feedback, education and monthly departmental reports.

The AMS team comprised infectious diseases specialists, a clinical microbiologist and a clinical pharmacist, supported by ward-level physician champions.

TZP and multidisciplinary AMS

The analysis included 156,035 adult hospital admissions between 2022 and 2024, of which 92,346 (59.2%) occurred in departments exposed to AMS. Comparator departments did not receive the intervention and continued standard prescribing practices.

Following implementation, TZP use decreased significantly in AMS departments by 19.5% (95% CI: −25.5 to −13.5%; P < 0.001), while increasing by 26.7% in non-AMS departments (95% CI: 18.6–34.9%; P < 0.001).

The intervention was associated with improved prescribing processes. In point prevalence surveys for 262 TZP prescriptions, guideline adherence increased from 44.2% to 66.9% (OR: 2.32), documentation of indication from 50.7% to 75.8% (OR: 3.06), treatment planning from 4.3% to 30.6% (OR: 9.83) and reassessment within 72 hours from 16.7% to 49.2% (OR: 2.52).

These changes indicate improved clinical decision-making, documentation and review practices.

Changes in prescribing patterns also reflected a shift towards narrower-spectrum therapy, including increased use of benzylpenicillin (14.2%), ampicillin (20.2%) and aminoglycosides (36.4%) in AMS departments.

Clinical safety signals remained stable, with in-hospital mortality remaining unchanged (6.0% vs 6.1%; P = 0.962), and 30-day readmission rates decreasing from 11.6% to 10.2% (P = 0.0001).

Evaluating stewardship impact

However, several limitations were noted. The non-randomised design and inherent differences in case-mix between AMS and non-AMS departments introduce potential confounding. The point prevalence surveys were limited in size and frequency, and patient-level clinical and microbiological data were not available, restricting assessment of treatment appropriateness and resistance outcomes.

The authors emphasised that while stewardship interventions improved prescribing behaviour, hospital-level outcomes such as mortality may be insufficiently sensitive to detect modest clinical effects. Stewardship sustainability also emerged as a key challenge, with some attenuation of impact observed when intervention intensity decreased in 2024. The authors therefore acknowledged the need to integrate AMS into routine workflows instead of short-term project structures.

Overall, the findings support the integration of structured AMS interventions into routine clinical care and highlight the importance of active engagement with audit and feedback processes, adherence to empiric prescribing guidance and timely reassessment to optimise antimicrobial therapy without compromising patient safety.

At ESCMID Global 2025, Dr Carolina Garcia-Vidal, infectious diseases consultant at Hospital Clinic Barcelona, Spain, discussed how the novel antibiotic combination cefepime/enmetazobactam outperformed piperacillin/tazobactam in clinical cure and microbiological eradication in clinical trial data.

She also called for greater inclusion of these microbiome considerations in clinical guidelines.

Reference
Holler JG et al. Impact of a multi-disciplinary antimicrobial stewardship programme on piperacillin–tazobactam use at a Danish university hospital: a before-and-after interventional study. J Hosp Infect. 2026;170:81–91.