Genomic Characterization of Carbapenemase-Producing Klebsiella pneumoniae with Chromosomally Carried bla NDM-1.

We report here Klebsiella pneumoniae strains carrying chromosomal bla NDM-1 in Thailand. The genomes of these two isolates include a 160-kbp insertion containing bla NDM-1, which is almost identical to that in the IncHI1B-like plasmid. Further analysis indicated that IS5-mediated intermolecular transposition and Tn3 transposase-mediated homologous recombination resulted in the integration of bla NDM-1 into the chromosome from an IncHI1B-like plasmid. The spread of this type of carbapenem-resistant Enterobacteriaceae may threaten public health and warrants further monitoring.