Two high-risk clones of carbapenemase-producing Klebsiella pneumoniae that cause infections in pets and are present in the environment of a veterinary referral hospital.

Objectives: Infections with carbapenem-resistant Enterobacterales (CRE) are an emerging problem in pets and a major threat to public health. We determined the genetic relationships among carbapenemase-producing Klebsiella pneumoniae (CPKp) strains causing infections in hospitalized pets in a veterinary clinic and those found in the environment.

Methods: WGS was performed with both the Illumina and Nanopore platforms. Searches of genetic features were performed using several databases and bioinformatics tools, and phylogeny was assessed by whole-genome MLST (wgMLST) using SeqSphere and SNP calling with Snippy.

Results: WGS analysis of the CPKp strains identified all environmental and almost all animal strains as the high-risk clone ST11, with the exception of two strains that belonged to ST307. All CPKp belonged to novel complex types (CTs) and carried a conjugative 63 kb IncL plasmid encoding the carbapenemase gene blaOXA-48, yersiniabactin and other virulence factors. Although all CPKp ST11 strains carried additional similar IncR plasmids harbouring multiple antimicrobial resistance genes (ARGs), such as the plasmid-mediated blaDHA-1 AmpC gene, some structural variations were observed. The two ST307 strains carried identical 156 kb MDR IncFIB(K) plasmids with several ARGs, including the blaCTX-M-15 ESBL gene. Both wgMLST and cgSNP analysis confirmed that CPKp strains of the same ST were genetically highly related independent of the source of isolation.

Conclusions: This study demonstrated that the clinical CPKp strains were highly related to those contaminating the clinical environment. These findings confirmed nosocomial spread and highlight veterinary hospitals as a source of CPKp, which may further spread to animals, the environment and humans.