blaVIM-2-Harboring integrons isolated in India, Russia, and the United States arise from an ancestral class 1 integron predating the formation of the 3′ conserved sequence

The metallo-beta-lactamase gene bla(VIM-2) was identified in a strain of Pseudomonas aeruginosa isolated in India. The integron encoding bla(VIM-2) was virtually identical to those recently found in the United States and Russia. These unusual structures are likely to have arisen from an ancestral integron predating the formation of the 3 ' conserved sequence.