Genomic and phenotypic characterization of carbapenem-resistant Acinetobacter baumannii isolates from patients and trolleys and their potential connections in an intensive care unit.

BACKGROUND

Carbapenem-resistant Acinetobacter baumannii (CRAB) poses significant challenges in intensive care units (ICU) due to its multidrug resistance and environmental persistence. To date, most studies have focused on clinical isolates or patient-environment transmission. However, high-touch mobile surfaces have been less extensively characterized.

RESULTS

We collected 49 CRAB isolates in 2019 and 2021 from ICU patients (n = 32) and trolley surfaces (n = 17). 91.84% (45/49) isolates belonged to ST2Pas and carried blaOXA-23. The capsular polysaccharide (K locus) and lipopolysaccharide (OC locus) types were predominantly KL7 and OCL1, respectively. Comparative genomic analysis revealed a high degree of genomic relatedness between patient and trolley associated isolates, including three clonal clusters (SNP differences < 19). To further characterize environmental persistence, we assessed biofilm formation using Live/Dead staining and scanning electron microscopy (SEM), and evaluated disinfectant susceptibility across all isolates.

CONCLUSIONS

These findings demonstrate the coexistence of closely related CRAB on patients and trolley surfaces within the same ICU and highlight the importance of considering high-touch mobile surfaces in infection prevention and control (IPC) strategies.

TRIAL REGISTRATION: ClinicalTrials.gov, NCT04310722. Registered on 18 March 2020. Retrospectively registered.