Where antibiotic time-outs work: department- and ward-stratified effects of a pharmacist-led anti-MRSA time-out

To assess the impact of a pharmacist-led anti-methicillin-resistant Staphylococcus aureus (MRSA) agents' time-out and identify clinical areas most likely to benefit.

Single-center before-after interrupted time-series study.

An 813-bed tertiary hospital in Tokyo, Japan.

Inpatients receiving intravenous anti-MRSA agents.

Stewardship pharmacists alerted physicians to reassess intravenous anti-MRSA therapy at 72 hours after its start. Monthly days of therapy per 1,000 patient-days (DOT) were compared between October 2017 to September 2022 and October 2022 to September 2024 after stratification by ward and department. Acceptance rate and therapeutic drug monitoring (TDM) tests were also assessed.

Hospital-wide DOT showed an immediate non-significant decrease (-19.23; 95% confidence interval [CI] -59.17 to 20.72; P = .35) and no significant trend change (+0.82; 95% CI -1.18 to 2.82; P = .42). In emergency medicine, DOT decreased in critical care (slope change -20.3; 95% CI -36.25 to -4.28; P = .01) and general wards (-31.6; 95% CI -61.4 to -1.79; P = .04). In emergency medicine critical care, vancomycin use decreased (level change -406.1; 95% CI -801.3 to -10.9; P = .04) with a reduced trend (slope change -24.5; 95% CI -41.2 to -7.8; P < .001). Acceptance was higher in critical care than in general wards (77.1% [27/35] vs 33.6% [40/119]). TDM tests per 1,000 patient-days decreased (8.47 ± 2.39 to 6.55 ± 1.18; P < .001), with no increase in length of stay or in-hospital mortality.

Targeting an implementation to areas most likely to benefit from it may improve antimicrobial stewardship when resources are limited. Complementary strategies may be needed if acceptance is poor.