Pharmacist-coordinated IDST treatment bundle achievement and impact on mortality in MRSA bacteraemia: a single-centre retrospective cohort study.

BACKGROUND

Methicillin-resistant Staphylococcus aureus (MRSA) bacteraemia carries high mortality. At Yamanashi Prefectural Central Hospital, antimicrobial stewardship has focused on appropriate drug use. In 2022, a pharmacist-coordinated Infectious Disease Support Team (IDST) was established to optimize management, including diagnostics, dosing, and treatment duration. We evaluated the effects of IDST participation on the adherence to a predefined Staphylococcus aureus bacteraemia treatment bundle and mortality.

METHODS

We conducted a single-centre retrospective cohort study of adults with MRSA bacteraemia diagnosed between April 2020 and June 2025. Patients were categorized into IDST intervention or non-intervention groups. Bundle adherence (≥ 75% defined as ≥ 9/12 items) and 28- and 90-day mortality were analysed using Kaplan-Meier analysis with log-rank tests and Cox proportional-hazards models; two-sided P < 0.05 was considered significant.

RESULTS

Eighty-five patients were included in the present study. Overall, bundle adherence ≥75% occurred in 57.6%; adherence was higher with IDST than without (79.5% vs 39.1%); 28-day mortality occurred in 26 (30.6%) and 90-day mortality in 42 (49.4%), respectively. Survival analysis showed lower 28-day (log-rank P=0.031) and 90-day mortality (P=0.017) with IDST. In multi-variable models, IDST remained independently protective at 28 days (hazard ratio [HR] 0.328, 95% CI: 0.136-0.792; P=0.013) and 90 days (HR 0.427, 95% CI: 0.215-0.846; P=0.015).

CONCLUSIONS

Pharmacist-coordinated IDST co-management significantly improved adherence to evidence-based care and was associated with reduced short- and intermediate-term mortality in patients with MRSA bacteraemia. This model may be applicable to hospitals with limited continuous on-site availability of infectious disease physicians, provided that specialist oversight remains accessible.