Genomic insight into the distribution and genetic environment of bla_IMP-4 in clinical carbapenem-resistant Klebsiella pneumoniae strains in China

Carbapenem-resistant Klebsiella pneumoniae (CRKP) poses a major threat to public health due to its resistance to almost all antibiotics. It is associated with substantial morbidity and mortality and poses a significant challenge to healthcare systems around the globe. Based on our previous nationwide survey of carbapenem-resistant Enterobacteriaceae (CRE) in China, seven bla_IMP-4-carrying CRKP isolates were identified, all exhibiting MDR and epidemiologically linked to four different regions in China. WGS analysis revealed that the seven bla_IMP-4 genes were all located on plasmids, of which five bla_IMP-4 genes were located on the IncHI5 plasmids and the other two belonged to the IncN and IncFII_K plasmids, respectively. Except for the IncHI5 plasmid, conjugation assays revealed that the IncN and IncFII_K plasmids could be transferred to the recipient strain Escherichia coli J53. This study revealed significant genetic variation and identified numerous resistance factors among bla_IMP-4-carrying CRKP strains in China, suggesting that bla_IMP-4-carrying CRKP strains evolved via multiple phylogenetic routes and highlighting a need for expanded surveillance and establishment of control measures to prevent dissemination of CRKP strains, and facilitate development of more effective antibiotic stewardship policies and infection control programs. © 2023. Published by Elsevier GmbH.