Co-occurrence of blaIMP-4 and blaKPC-2 in a clinical isolate and global evolutionary genomics of Klebsiella grimontii

Klebsiella grimontii is a recently confirmed member of the Klebsiella oxytoca complex with significant clinical importance. As an opportunistic pathogen, reports of infections it causes are increasing, and the associated threats warrant attention. However, its phylogeny and epidemiological patterns remain poorly studied. In this study, we identified a strain of Klebsiella grimontii , designated K767, simultaneously carrying the carbapenemase genes bla IMP-4 and bla KPC-2 through phenotypic assays and sequencing techniques from a tertiary hospital in Zhejiang Province, China. After performing whole-genome analysis of this strain, we integrated data from the NCBI public database, incorporating genomic information from a total of 235 Klebsiella grimontii strains for in-depth bioinformatics analysis. Genomic analysis revealed that in strain K767, bla IMP-4 is located on an IncHI5-type plasmid. This plasmid harbors multiple resistance modules and is highly conserved among similar plasmids originating from China. bla KPC-2 is located on an IncFII:IncFIA-type hybrid plasmid, a type predominantly found in Klebsiella species within China. Analysis of the 235 global strains indicated spatiotemporal heterogeneity in the distribution of sequenced isolates, with Europe contributing the most genomes. A total of 76 sequence types were identified, with Cluster III being the predominant evolutionary clade. The strains carried 75 acquired antimicrobial resistance genes, including various carbapenemase genes, and a significant co-occurrence was observed between certain resistance genes and specific plasmid replicons. This study reports a strain of Klebsiella grimontii simultaneously carrying bla IMP-4 and bla KPC-2 . These genes are carried by an IncHI5-type conjugative plasmid and an IncFII:IncFIA-type hybrid plasmid, respectively, both of which have been detected in sequenced isolates from China. Global population analysis suggests that this species exhibits high genetic diversity, with spatiotemporal heterogeneity in the distribution of sequenced isolates, and that plasmids may serve as potential vehicles for resistance genes. The findings provide an important basis for the clinical prevention and control of such resistant pathogens.