Genomic characterization of a -producing IncM2 plasmid harboring transposon ΔTn in .

is an emerging hospital-acquired bacterial pathogen, particularly strains harboring plasmid-mediated carbapenemase genes. Here, we recovered and characterized a multidrug-resistant strain, -producing LS81, which was isolated from the abdominal drainage fluid of a clinical patient in China, and further characterized the co-harboring plasmid. LS81 tested positive for the genes by PCR sequencing, with located on a plasmid as confirmed by S1 nuclease pulsed-field gel electrophoresis combined with Southern blotting. In the transconjugants, the genes were successfully transferred to the recipient strain EC600. Whole-genome sequencing and bioinformatics analysis confirmed that this strain belongs to sequence type 196 (ST196), with a complete genome comprising a 5,926,662bp circular chromosome and an 81,451bp IncM2 plasmid encoding (designated pLS81-KPC). The IncM2 plasmid carried multiple β-lactamase genes such as , , and inserted in truncated Tn with the distinctive core structure IS- -IS. A comparison with 46 genomes available in the NCBI database revealed that the closest phylogenetic relative of LS81 is a clinical isolate from a wound swab in the United Kingdom. Ultimately, the pan-genomic analysis unveiled a substantial accessory genome within the strain, alongside significant genomic plasticity within the species, emphasizing the necessity for continuous surveillance of this pathogen in clinical environments.