# Impact of a tailored, department-specific antimicrobial stewardship team intervention based on AWaRe guidelines: a single-center, cohort, interrupted-time series study

## TL;DR

A targeted antimicrobial stewardship program successfully shifted outpatient antibiotic prescribing toward safer choices, but challenges like resistance and treatment duration remain.

## Contribution

Demonstrated that department-specific educational interventions can effectively shift prescribing from Watch to Access antibiotics in outpatient settings.

## Key findings

- AST interventions increased Access antibiotic use by 2.92% and DDDs by 376.5, while decreasing Watch antibiotics by 3.00%.
- E. coli resistance to levofloxacin and ciprofloxacin was low overall but high in ESBL-producing strains.
- Sulfamethoxazole/trimethoprim remained highly susceptible overall but showed low efficacy against ESBL-producing strains.

## Abstract

The global crisis of antimicrobial resistance (AMR) necessitates robust antimicrobial stewardship. The World Health Organization’s (WHO) Access, Watch, Reserve (AWaRe) classification is a key tool for guiding antibiotic prescribing to combat AMR. The WHO’s global target was to have at least 60% of antibiotic consumption fall into the Access category by 2023. This study evaluated the effectiveness of localized interventions toward this goal.

This retrospective, longitudinal study analyzed oral outpatient antibiotic prescriptions at Kochi Medical School Hospital from April 2022 to June 2025. Data included defined daily doses (DDDs), days of therapy (DOTs), and AWaRe classifications. Based on a preceding analysis, the antimicrobial stewardship team (AST) implemented targeted, department-specific educational interventions starting in April 2024. The impact was evaluated using seasonally adjusted time-series analysis and regression models. The study also included a survey of Escherichia coli susceptibility to levofloxacin, ciprofloxacin, and sulfamethoxazole/trimethoprim from outpatient urinary isolates.

The AST intervention led to a statistically significant increase in the usage proportion and DDDs of Access antibiotics (+ 2.92%, p = 0.005 and + 376.5 DDDs, p = 0.001, respectively), with a corresponding decrease in Watch antibiotics (-3.00%, p = 0.003). However, DOTs did not significantly change, indicating the intervention primarily impacted drug choice, not treatment duration. Top prescribed agents were clarithromycin (24.2%), sulfamethoxazole/trimethoprim (20.7%), and rifaximin (10.7%). E. coli susceptibility to levofloxacin and ciprofloxacin was low (< 80% overall), particularly in extended-spectrum β-lactamase (ESBL)-producing strains (~ 10%). Sulfamethoxazole/trimethoprim susceptibility remained high overall (≥ 80%) but was low (< 80%) for ESBL-producing strains.

AST interventions successfully shifted outpatient prescribing from Watch to Access antibiotics, demonstrating that targeted interventions can modify prescribing behavior. However, challenges remain, such as addressing treatment duration and achieving broader goals. The observed resistance patterns highlight the critical need for prescribers to consult local antibiograms. Future strategies require a more comprehensive approach, including real-time alerts and improved diagnostics, to further optimize antibiotic use and combat AMR.

The online version contains supplementary material available at 10.1186/s40780-025-00525-3.