Impact of Carbapenem Targeted Antimicrobial Stewardship Interventions: an Interrupted Time-Series Analysis

The development of carbapenem-resistant Gram-negative bacilli (CR-GNB) is largely favoured by indiscriminate and prolonged carbapenem use, which is a significant contributing factor.To evaluate the impact of two carbapenem antibiotic stewardship programme interventions on both carbapenem prescriptions and the clinical isolation rates of CR-GNBs, using interrupted time-series analysis.A time-series analysis was performed using data for carbapenem usage from a tertiary hospital in South Korea from January 2017 to July 2022. Two carbapenem antibiotic stewardship programme interventions were implemented sequentially: (i) a prospective audit and feedback (PAF) from November 2018 to April 2020 (intervention 1), and (ii) preauthorization from May 2020 to August 2020 (intervention 2). Monthly carbapenem usage and incidence of CR-GNB before and after each intervention were compared using an autoregressive integrated moving average model.Implementation of PAF resulted in a significant reduction in carbapenem consumption, followed by an additional decrease after the preauthorization was implemented. The incidence of carbapenem-resistant Escherichia coli and Klebsiella pneumoniae increased after intervention 1, but there was a significant change from an increasing trend to a stationary trend after intervention 2. The incidence of carbapenem-resistant Pseudomonas aeruginosa, which had increased during the baseline period, became stationary after intervention 1. A significant decrease was observed in the incidence of carbapenem-resistant Acinetobacter baumannii during the implementation of intervention 1 and 2.This study emphasizes the importance of adopting comprehensive antibiotic management and rigorous infection control to prevent infections caused by antibiotic-resistant bacteria.