Genomic epidemiology of dual carbapenemase-producing Klebsiella pneumoniae and identification of an ST23-KL1 blaKPC-2/blaIMP-4 co-producing isolate in a Chinese tertiary hospital

The convergence of hypervirulence and multidrug resistance in K. pneumoniae poses a serious and emerging threat to global health. Here, we conducted genomic characterization of 40 dual carbapenemase-producing K. pneumoniae (DC-KP) isolates collected from a Chinese tertiary hospital. Whole-genome sequencing revealed that bla KPC-2 / bla NDM-5 was the predominant carbapenemase combination, and most isolates belonged to the ST11 lineage. Low MICs of ATM + AVI and ATM + CZA were observed for 38 of the 40 DC-KP isolates, indicating substantial in vitro activity against most isolates in this cohort. Notably, we identified an ST23-KL1 K. pneumoniae isolate co-harboring bla KPC-2 and bla IMP-4 and carrying multiple hypervirulence-associated determinants. To our knowledge, this is the first report of an ST23-KL1 isolate with this combination of carbapenemase genes. RM/Anti-RM-associated gene counts differed among isolates with different carbapenemase profiles, warranting further investigation. These findings provide genomic insights into the coexistence of carbapenem resistance and hypervirulence-associated traits in K. pneumoniae.