International journal of antimicrobial agents | 2021
Phenotypic and Molecular Characterisations of Carbapenem-resistant Acinetobacter baumannii Isolates Collected within the EURECA Study.
Abstract
Multidrug-resistant Acinetobacter baumannii isolates are key pathogens that contribute to the global burden of antimicrobial resistance. This study aimed to investigate the phenotypic and molecular characteristics of carbapenem-resistant A. baumannii (CRAB) isolates from the EURECA clinical trial. In total, 228 CRAB clinical strains were recovered from 29 sites in 10 European countries between May 2016 and November 2018 participating in EURECA. All strains were reconfirmed centrally for identification and antimicrobial susceptibility testing and they were then subjected to DNA isolation, and whole-genome sequencing (WGS) with analysis performed using BacPipe v.1.2.6. The K and O typing was done using KAPTIVE. Overall, 226 (99.1%) of the strains were confirmed as CRAB isolates. The MIC90 results of imipenem and meropenem were >16 mg/L. WGS showed that isolates harboured mainly blaOXA-23 (n=153; 67.7%) or blaOXA-72 (n=70; 30.1%). Four blaOXA-72 isolates from Serbia co-harboured also blaNDM-1. An IS5 transposase family element, ISAba31, was found upstream of the blaOXA-72 gene harboured on a small (∼10-kb) pSE41030-EUR plasmid. The majority of isolates (n=178; 79.1%) belonged to international clone II. The strains belonging to the same STs but isolated in different countries and within the same country could be delineated in different clusters by cgMLST. Whole-genome/core-genome based multilocus sequence (cg/wgMLST) analysis showed high diversity among the isolates and the most common ST being ST2 (n=153; 67.7%). The EURECA A. baumannii strain collection represents a unique, diverse repository of CR isolates that adds to the existing knowledge of A. baumannii epidemiology and resistance genes harboured by these strains.