Emergence of Pseudomonas aeruginosa strains producing metallo-beta-lactamases of the IMP-15 and VIM-2 types in Mexico.

Eighty-six carbapenem non-susceptible Pseudomonas aeruginosa isolates collected in the National Institute of Respiratory Diseases of Mexico City were screened for the presence of metallo-beta-lactamase (MBL) activity using both E-test strips and a microbiological assay with EDTA-imipenem. Genomic comparisons and sequence analyses conducted with these isolates revealed the presence of bla(VIM-2) in two clonally related isolates, and bla(IMP-15) in a clonally unrelated isolate. Both genes were found to be carried by class 1 integrons, and bla(IMP-15) was additionally present on a broad host-range plasmid.