Characterization of an IncN2-type blaNDM-1-carrying plasmid in Escherichia

The prevalence of New Delhi metallo-b-lactamase-1 (NDM-1), encoded by the blaNDM-1 gene, has been increasing among various Gram-negative bacteria.1 blaNDM-1 has been shown to reside in various plasmid incompatibility (Inc) types.1 Recently, a new Inc type, IncN2, has been identified in Escherichia coli and Klebsiella pneumoniae and proposed to acquire the blaNDM-1-carrying region by transposition.2,3 In Thailand, NDM-1 producers have become an emerging issue,4 and yet the characteristics of the blaNDM-1-carrying plasmid have not been elucidated. Here we report the genetic study of plasmids harbouring blaNDM-1 from domestic isolates. We examined three clinical isolates, one E. coli (ECS01) and two K. pneumoniae (KPS01 and KPS03), which were obtained from urine samples of independent Thai patients at two unrelated hos-pitals during June to August 2012 (IRB approval no. Si 454/2009). No previous hospitalization, antimicrobial exposure or healthcare