Tailoring Interventions for Control of Endemic Carbapenem-Resistant Acinetobacter baumannii: An Interrupted Time Series Analysis

Abstract

Background We examined temporal trends in carbapenem-resistant Acinetobacter baumannii (CRAB) infections in one hospital with hyperendemic CRAB, and assessed the efficacy of varied infection control strategies in different ward types. Methods We retrospectively analyzed all CRAB clinical samples from 2006 to 2019, and categorized infections as hospital-onset (HO) or community-onset. We used interrupted time series analysis to assess the impact of interventions on the incidence of all HO-CRAB infections and bloodstream infections (BSI) at the hospital and ward-group levels. Results Over 14 years, 4,009 CRAB infections were identified (89.7% HO), with 813 CRAB BSI (93.2% HO). The incidence per 100,000 patient-days of CRAB infections peaked at 79.1 in 2008, and that of CRAB BSI peaked at 16.2 in 2010. These rates decreased by two-thirds by 2019. In the general ICU, hand hygiene and environmental cleaning interventions were followed by a significant reduction in the level of HO-CRAB infections, with an additional decrease in the slope after the introduction of active surveillance and 2% chlorhexidine bathing. In the surgical ICU and surgical department, a reduction in slope or level of CRAB infection was observed after moving ventilated patients to single rooms. In medical wards, a multi-modal intervention was followed by a reduction in the slope of HO-CRAB infections and BSI. In wards where CRAB infections were uncommon, the incidence of HO-CRAB infections decreased throughout the study period. Conclusion Ward-specific variables determine the success of interventions to reduce CRAB infections; therefore, interventions should be tailored to each setting.