Hospital outbreak of multiple clones of Pseudomonas aeruginosa carrying the unrelated metallo-beta-lactamase gene variants blaVIM-2 and blaVIM-4.
OBJECTIVE
The possible contribution of metallo-beta-lactamases in the frequent detection of carbapenem-resistant Pseudomonas aeruginosa isolates in a tertiary Greek hospital in Central Greece was investigated.


METHODS
All carbapenem-resistant (imipenem- and/or meropenem-resistant) P. aeruginosa isolates recovered from separate patients during a 1 year period in the Clinical Microbiology Laboratory at the University Hospital of Thessaly, Larissa, Greece, were studied for metallo-beta-lactamases. They were tested by Etest MBL, PCR analysis and nucleotide sequencing. DNA fingerprints were obtained by pulsed-field gel electrophoresis (PFGE) of XbaI-digested chromosomal DNA.


RESULTS
A blaVIM gene was detected in 47 of the 53 (88.7%) carbapenem-resistant P. aeruginosa isolates. PFGE grouped the blaVIM-positive isolates in six unrelated genotypes; one type included two subtypes. Nucleotide sequencing of the PCR amplicons of a randomly selected isolate from each one of the seven subtypes, detected the variant sequences blaVIM-2 in four and blaVIM-4 in three cases, respectively. They were carried as single gene cassettes or along with an aminoglycoside resistance gene (aacA29a) in class 1 integrons.


CONCLUSIONS
These findings suggest that different strains of P. aeruginosa carrying unrelated metallo-beta-lactamase gene variants predominate in our hospital environment.
Pournaras
S
S
Department of Microbiology, University Hospital of Thessaly, Mezourlo, Larissa 412 22, Greece. pournaras@med.uth.gr
Maniati
M
M
Petinaki
E
E
Tzouvelekis
L S
LS
Tsakris
A
A
Legakis
N J
NJ
Maniatis
A N
AN
D000900:Anti-Bacterial Agents / Q000494:pharmacology / Q000627:therapeutic use; D002999:Clone Cells / Q000187:drug effects; D003428:Cross Infection / Q000188:drug therapy / Q000382:microbiology*; D004196:Disease Outbreaks; D024881:Drug Resistance, Bacterial / Q000235:genetics; D014644:Genetic Variation / Q000235:genetics*; D006801:Humans; D011552:Pseudomonas Infections / Q000188:drug therapy / Q000382:microbiology*; D011550:Pseudomonas aeruginosa / Q000187:drug effects / Q000201:enzymology / Q000235:genetics*; D001618:beta-Lactamases / Q000235:genetics*
D000900:Anti-Bacterial Agents; C425108:beta-lactamase bla(vim-2); D001618:beta-Lactamases; C477893:beta-lactamase bla(VIM-4), Pseudomonas aeruginosa