Impact of an antimicrobial stewardship bundle on the outcome of high-risk neutropenic patients with fever: a pre-post study.

Background: Rapid antibiotic initiation is essential for managing potential infections following chemotherapy-induced neutropenia. However, excessive use of broad-spectrum antibiotics should be avoided. Implementing antimicrobial stewardship (AMS) in haematology units is challenging due to high infection-related risks, and data on interventions remain scarce. This study aimed to evaluate the safety of an AMS bundle on a haematology ward. Methods: A prospective cohort study was conducted at a tertiary care centre among patients with high-risk (≥7 days) neutropenia. The AMS bundle consisted of replacing empirical meropenem with ceftazidime, and shortening treatment duration to 2 days in case of defervescence and negative blood cultures. Data on ICU admission, all-cause mortality, antimicrobial use and microorganisms identified were compared with a (retrospective) pre-intervention cohort. Results: A total of 396 patients were included (206 pre-intervention, 190 post-intervention). Allogeneic stem cell transplantations increased from 21% pre-intervention to 37% post-intervention. There was no statistical difference in the adjusted composite endpoint of ICU admission and all-cause mortality [adjusted HR (aHR) 1.46; 95% CI, 0.76-2.81; Conclusions: The AMS bundle led to a shift towards narrower-spectrum antibiotics, and reduced treatment duration and overall antibiotic use without a significant impact on the primary safety outcome. The intervention was accompanied by a declining trend in candidaemia incidence.