Complete genome characterisation and comparative plasmidome analysis of isolates of A. radioresistens of clinical origins encoding for class B & D beta-lactamases associated with Irish hospital environment, human colonisation and infection.

Four isolates of Acinetobacter radioresistens were isolated from clinical and environmental samples collected from different Irish hospitals. Genomes were sequenced using Illumina MiSeq (PE300), filtered with fastp, assembled with Shovill, and quality-assessed with QUAST and CheckM. Annotation wasperformed using PROKKA. To contextualise results within a broader genomic framework, a pan-genome analysis was conducted including all currently publicly available A. radioresistens genomes (n=58), and taxonomic placement was confirmed via GTDB-Tk. Genomic presence of resistance, virulence, and biocide/metal resistance genes was investigated using Abricate with CARD, VFDB, and BacMet databases. Phenotypic resistance to 12 clinically relevant antibiotics was further confirmed by Antimicrobial Susceptibility Testing (AST). The present results reveal the first instance of A. radioresistens reportedely causing an infection (urinary trait) in Ireland, and the first case of A. radioresistens harbouring acquired carbapenem resistance in Ireland (blaNDM-1). Notably, only one other A. radioresistens strain carrying blaNDM-1 has been reported in the literature.