Characterization of a Novel Putative Xer-Dependent Integrative Mobile Element Carrying the blaNMC-A Carbapenemase Gene,Inserted into the Chromosome of Members of the Enterobacter cloacae Complex

An Enterobacter ludwigii strain was isolated during routine screening of a Japanese patient for carriage of carbapenem-resistant Enterobacteriaceae. PCR analysis revealed the bla_NMC-A carbapenemase gene. Whole-genome sequencing revealed that bla_NMC-A was inserted in the chromosome and associated with a novel 29.1-kb putative Xer-dependent integrative mobile element, named EludIMEX-1. Bioinformatic analysis identified similar elements in the genomes of an Enterobacter asburiae strain and of other Enterobacter cloacae complex strains, confirming the mobile nature of this element.