Characterization of Tn3000, a transposon responsible for bla_NDM-1 dissemination among Enterobacteriaceae in Brazil, Nepal, Morocco, and India

In Enterobacteriaceae, the bla_NDM genes have been found in many different genetic contexts, and a wide diversity of plasmid scaffolds bearing those genes has been found. In August 2013, we identified NDM-1-producing Escherichia coli and Enterobacter hormaechei strains from a single rectal swab sample from a patient hospitalized in Rio de Janeiro, Brazil, who had no history of travel abroad. Complete DNA sequencing using the Illumina platform and annotation of the two plasmids harboring the bla_NDM-1 gene, one from each strain, showed that they belonged to incompatibility groups IncFII_K and IncX3 and harbored a novel transposon named Tn3000. Similar genetic structures have been identified among other isolates in Brazil but also on plasmids from other continents. Our findings suggest that the bla_NDM-1 gene may be transmitted by Tn3000 in different parts of the world.