Probable interspecies transfer of the blaVIM-4 gene between Enterobacter cloacae and Klebsiella pneumoniae in a single infant patient

We report the interspecies transfer of the blaVIM-4 gene in MBL-producing Enterobacter cloacae and Klebsiella pneumoniae isolates from a newborn patient who had received meropenem therapy. We show evidence that gene blaVIM-4 was transmitted as a part of the class-1 integron on a ca. ~90 kb conjugative plasmid. High homology of nucleotide sequence was observed between the integron found in VIM-4 producing E. cloacae and K. pneumoniae strains tested and class-1 integrons previously reporteded in Pseudomonas aeruginosa from Hungary and Poland. This finding may suggest P. aeruginosa as a potential source of acquired VIM-4 in Enterobacteriaceae.