Molecular epidemiology and clinical significance of carbapenemase genes among carbapenem-resistant Acinetobacter baumannii isolates in southern Poland

ABSTRACT

Introduction: The complex interplay between Acinetobacter spp., patients, and the environment has made it increasingly difficult to optimally treat patients infected with Acinetobacter spp., mainly due to rising antimicrobial resistance and challenges with surveillance.

Objectives: This study evaluated carbapenem-resistance Acinetobacter baumannii (CRAB) isolates to determine their resistance profiles and the presence of specific β-lactamase enzymes to inform the use of CRAB surveillance upon hospital admission and regional empiric antibiotic therapies.

Patients and methods: The study was conducted at 4 hospitals in southern Poland between June 2022 and December 2022. Only healthcare-associated infections caused by Acinetobacter baumannii were considered. 82 CRAB isolates were included in the analysis. Species identification was performed by MALDI TOF, antimicrobial susceptibility was determined phenotypically, and PCR methods were performed to identify resistance genes.

Results: Depending on the hospital, the ICU incidence of CRAB infections was from 428.6 to 759.5 per 10,000 admissions and from 0.3 to 21.0 per 10,000 admissions in non-ICUs. CRAB antibiotic susceptibility was highest with cefiderocol (100%), colistin (96%), tigecycline (77%), gentamicin (51%) and ampicillin / sulbactam (36%). The most prevalent blaOXA genes were blaOXA-66-1 (95%) and blaOXA-40 (71%) and additionally, the extended-spectrum β-lactamase gene blaTEM-1 (41%).

Conclusion: An unexpectedly high incidence of CRAB infections occurred in Polish hospitals. There is a need for effective CRAB prevention and control that includes effective hospital screening, national surveillance, and improved treatment options.