Emerging and re-emerging KPC-producing hypervirulent ST697 and ST463 between 2010 and 2021.

Carbapenem-resistant (CRPA) has been a major threat to human health due to its increased morbidity and mortality in clinical settings. Carbapenemase genes are less frequently found in CRPA compared with carbapenem-resistant , of which carbapenemase producers are common. In this study, we identified 11 -harbouring isolates from 139 carbapenemase-insensitive . isolates collected between 2010 and 2021 in a tertiary hospital in China. Nine isolates belonged to ST697, while the other two were ST463. The antibiotic susceptibility testing showed that all the isolates were multidrug resistant, including resistance to imipenem, meropenem, ceftazidime, and tigecycline. Patients with carbapenemase-2 (KPC-2)-producing infections were mostly associated with complicated diseases and prolonged hospital stay, with 30% deterioration. The whole-genome sequencing analysis showed that these isolates carried multiple antibiotic resistance genes and virulence genes, and the KPC-2 genetic elements were highly related in ST697 isolates. The complete sequencing of ST697 isolate SE5416 showed that the harbouring of resulted from complex transposition and homologous recombination of an Inc plasmid and other mobile elements. The infection model experiment showed that these KPC-2-producing . -infected larvae had low survival rates and high virulence. The present study revealed the shifting of CRPA from ST697 to ST463 in East China; ST463 had higher drug resistance, posing greater challenges for clinical management.