Genome Characteristic of NDM-5-Producing Klebsiella Quasipneumoniae and Klebsiella Pneumoniae in China.

The global dissemination of carbapenem-resistant Enterobacteriaceae poses a significant threat to public health. In this study, we identified two clinical Klebsiella isolates, K. quasipneumoniae ACESH02628 and K. pneumoniae ACESH02857, harboring the bla _NDM-5 gene in China. Both strains exhibited multidrug resistance, including reduced susceptibility to carbapenems, and carried transferable NDM-5-bearing plasmids. Specifically, S1-pulsed-field gel electrophoresis (PFGE), southern blotting, and whole-genome sequencing revealed that ACESH02628 contained an IncHI2/IncHI2A-type plasmid, while ACESH02857 carried an IncX3-type plasmid, both associated with the regional spread of NDM-5. Comparative analyses showed high genetic similarity with previously reported NDM-5 plasmids from Salmonella enterica and Escherichia coli in China, underscoring the ease of horizontal transfer and potential for broader dissemination. Our findings highlight the emergence of NDM-5-producing K. quasipneumoniae of clinical origin and reinforce the need for vigilant surveillance and infection control measures to curb the proliferation of these highly resistant pathogens.