Impact of cohorting carbapenem-resistant Acinetobacter baumannii (CRAB) patients combined with enhanced environmental cleaning on CRAB bloodstream infections: a prospective surveillance-based study.

Background: Carbapenem-resistant Acinetobacter baumannii (CRAB) infections carry high case-fatality rates. Although the incidence of these infections is increasing and therapeutic options are limited, effective interventions to prevent the cross-transmission of CRAB have rarely been tested.

Aim: To assess the impact of cohorting CRAB patients combined with intensified environmental cleaning on CRAB bloodstream infections (BSI).

Methods: A quasi-experimental study at a tertiary hospital during January 2022 - June 2024. We cohorted all patients with CRAB (either colonization or infection) hospitalized in the internal medicine departments. Simultaneously, we performed a twice-daily routine and a double terminal cleaning of all hospital rooms occupied by CRAB patients. We calculated the monthly acquired CRAB BSI rates and estimated the incidence rate ratio (IRR) using Poisson regression discontinuity analysis with robust standard errors controlled for the influx of CRAB patients into the hospital.

Findings: During January 2022 to June 2024, we identified 610 hospitalized patients with CRAB, 350 (57%) of whom acquired the bacterium in hospital and 138 (39%) developed BSI. The average overall 30-days mortality rate was 61% and remained relatively similar throughout the study period. Cumulative BSI incidence decreased by 55%, from 1.43 per 10,000 hospitalization days before the intervention to 0.65 afterwards. The slope of the BSI incidence rate decreased by 9% per month (adjusted IRR 0.909, 95% CI 0.834-0.990, p=0.029).

Conclusions: Cohorting CRAB patients in the internal medicine departments, combined with intensified cleaning throughout the hospital significantly reduced the incidence of CRAB BSI across the entire institution.