A study was designed to investigate the molecular epidemiological characteristics of multidrug-resistant outbreak-related Pseudomonas aeruginosa isolates collected in a university hospital in northern Greece. Of 29 nonreplicate P. aeruginosa isolates resistant to carbapenems and ceftazidime, 14 were positive for metallo-β-lactamase production. PCR analyses with primers specific for bla_VIM and bla_IMP revealed that 13 isolates carried a novel bla_VIM-2 gene variant, designated bla_VIM-17, and only 1 isolate carried bla_VIM-2, a gene predominant among P. aeruginosa strains in Greek hospitals. Pulsed-field gel electrophoresis of XbaI-digested genomic DNAs showed a close genetic relationship for 12 of 13 bla_VIM-17-carrying outbreak-related isolates, which were of the O11 serotype; the clonally unrelated isolate carrying bla_VIM-17 was of the O12 serotype. PCR mapping strategies for the detection of class 1 integrons and sequencing approaches revealed the presence of integrons containing one bla_VIM cassette flanked by two aacA29 cassettes. These integrons were similar but not identical to In59 (GenBank accession number AF263519) initially described in France. All isolates carrying bla_VIM-17, regardless of their genetic profile, had an identical integron, named In59.3, indicating that although the hospital outbreak was mainly due to clonal dissemination, the horizontal transmission of the bla_VIM-17-containing integron among P. aeruginosa isolates should also have occurred. An outbreak-related isolate and a control strain, both of which carried the bla_VIM-2 gene but which were clonally distinct, had an identical integron, named In59.2, which differed only at the level of the bla_VIM gene from In59.3 integrons, suggesting a common ancestry. The spread of the bla_VIM-17-containing integron in clonally unrelated P. aeruginosa isolates without any evidence of plasmid carriage is probably associated with a transposon.