Abstract

Objective: To genomically characterize Kpn-KPC-1, the first blaKPC-2-carrying Klebsiella pneumoniae isolate reported in Chile, and contextualize it within the global ST101 lineage. Methods: Kpn-KPC-1 was analyzed by whole-genome sequencing. Its resistome, virulome, plasmid content, and blaKPC-2 genetic context were characterized, and 537 publicly available ST101 genomes were used for comparative phylogenomics. Results: Kpn-KPC-1 belonged to ST101 and carried blaKPC-2 within the conventional Tn4401a transposon on a mosaic plasmid encoding multiple replication initiators and conjugation-associated genes. The isolate also harbored an OmpK36 porin alteration and accessory resistance-and virulence-associated determinants, including ICEKp3/ybt-9, K17, and O1 alpha beta,2 alpha. Phylogenomic analysis placed Kpn-KPC-1 within a predominantly European clade, closest to Italian isolates recovered between 2012 and 2018. The absence of additional Chilean ST101 isolates related to Kpn-KPC-1 supports limited local dissemination of this lineage. Globally, ST101 was enriched in carbapenemase genes, particularly blaOXA-48-like and blaKPC variants. Conclusions: Kpn-KPC-1 represents a transient introduction of a carbapenemase-prone, high-risk ST101 lineage rather than the founder of a locally disseminated clone in Chile. Genome-level analysis resolved the blaKPC-2 context in this historical isolate, linking the carbapenemase gene to Tn4401a on a mosaic multidrug-resistance plasmid within an imported ST101 background. These findings underscore the value of retrospective genomics for reconstructing early antimicrobial-resistance introduction events. (c) 2026 The Author(s). Published by Elsevier Ltd on behalf of International Society for Antimicrobial Chemotherapy. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/)