Molecular heterogeneity of blaVIM-2-containing integrons from Pseudomonas aeruginosa plasmids encoding the VIM-2 metallo-{beta}-lactamase

A bla</it><inf>VIM-2</inf> metallo-β-lactamase determinant, identical to that previously identified in Pseudomonas aeruginosa</it> COL-1 isolate from a French hospital, was detected on a 28-kb plasmid carried by a nosocomial isolate of P. aeruginosa</it> from Verona, Italy. In this plasmid the bla</it><inf>VIM-2</inf> determinant was inserted into a class 1 integron of original structure, named In72, that contains a partially deleted intI1</it> integrase gene and two gene cassettes. The first cassette carries an aacA4</it> aminoglycoside acetyl transferase determinant. The second cassette carries a bla</it><inf>VIM-2</inf> determinant followed by a partially deleted attC</it> site. The structure of In72 was notably different from that of In56, the bla</it><inf>VIM-2</inf>-containing integron found in the COL-1 isolate, revealing the existence of molecular heterogeneity among bla</it><inf>VIM-2</inf>-containing integrons in clinical isolates of P. aeruginosa</it> from Europe.