aeruginosa strains carrying bla VIM genes were found to constitute approximately 20% of all P. aeruginosa was detected in Sweden in 2004, and in this case, the isolate was also derived from a Greek patient (C. aeruginosa was reported from Poland ( 25, 42). Furthermore, detection of both VIM-2 and VIM-4 in P. aeruginosa were published from Sweden and Hungary in both cases, however, isolates were derived from Greek patients ( 11, 20). In 20, reports on the isolation of VIM-4 MBL-producing P. aeruginosa strains have recently been detected in northern and eastern Europe.

Although originally confined to the Mediterranean countries, VIM-producing P. In Europe, where they were first detected ( 17, 27), the VIM-type enzymes are the most prevalent overall ( 8, 43). The IMP- and VIM-type enzymes, which are encoded by integron-borne genes, are currently the most widespread, being reported from several continents, and several allelic variants are known for each type ( 43). Several types of these enzymes have been detected, namely, IMP, VIM, SPM, GIM, and SIM, mostly in Pseudomonas aeruginosa and other gram-negative nonfermenters, but also in Enterobacteriaceae ( 19, 43).

This is a matter of great concern because these enzymes can confer resistance to virtually all ОІ-lactams and are not susceptible to the clinically available ОІ-lactamase inhibitors ( 15). The emergence of metallo-ОІ-lactamases (MBLs) in major clinical pathogens was first described in the early 1990s in Japan and is now a problem of global magnitude ( 43). Comparison of the integrons carrying bla VIM-1-like cassettes of various isolates revealed a remarkable structural heterogeneity, suggesting the possibility that multiple independent events of acquisition of different bla VIM-containing integrons had occurred in members of the same clonal lineage, although a contribution of integrase-mediated cassette shuffling or other recombination mechanisms during the evolution of similar strains could also have played a role in determining this variability. Of these, one corresponded to the previously described BG4 and included serotype O12 strains from Hungary and Sweden, while the other two were novel and included serotype O11 or nonserotypable strains from Greece, Sweden, and/or Italy. The MBL producers belonged in three clonal complexes/burst groups (BGs). aeruginosa strains currently spreading in Europe. In particular, the recently developed MLST approach was useful in revealing clonal relatedness between isolates when this was not readily apparent using RAPD and PFGE, and it suggested a common ancestry for some of the VIM-1-like MBL-positive P. aeruginosa strains producing acquired MBLs. The four approaches yielded consistent results overall but showed different resolution powers in establishing relatedness between isolates (PFGE > RAPD > MLST > fliC typing) and could usefully complement each other to address issues in the molecular epidemiology of P. Ten multidrug-resistant Pseudomonas aeruginosa strains producing VIM-1-like acquired metallo-ОІ-lactamases (MBLs), isolated from four European countries (Greece, Hungary, Italy, and Sweden), were analyzed for genetic relatedness by several methodologies, including fliC sequence analysis, macrorestriction profiling of genomic DNA by pulsed-field gel electrophoresis (PFGE), random amplification of polymorphic DNA (RAPD), and multilocus sequence typing (MLST).

Greek question mark vim