Detection and Genetic Characterization of Metallo-β-Lactamase IMP-1 and VIM-2 in Pseudomonas aeruginosa Strains From Different Hospitals in Kermanshah, Iran.
BACKGROUND
Pseudomonas aeruginosais a frequent nosocomial pathogen that causes severe diseases in many settings. Carbapenems, including meropenem and imipenem, are effective antibiotics against this organism. However, the use of carbapenems has been hampered by the emergence of strains resistant to carbapenemsvia different mechanisms such as the production of metallo-β-lactamases (MBLs), which hydrolyze all carbapenems. Several kinds of MBLs have been reported, among them VIM and IMP types being the most clinically significant carbapenemases.


OBJECTIVE
We aimed to determine the distribution of bla VIM-2 and bla IMP-1 transferable genes encoding MBLs in P. aeruginosa isolated from three academic hospitals in Kermanshah.


METHODS
From 22nd June to 22nd September 2012, 225 isolates of P. aeruginosa were collected. These isolates were tested for antibiotic susceptibility with the Kirby-Bauer disk-diffusion method, and the MBLs were assessed using the imipenem-EDTA double-disk synergy test. The isolates were investigated for bla VIM - 2 and bla IMP-1 genes using polymerase chain reaction.


RESULTS
Among the 225 isolates, 33.7% (76/225) and 18.1% (41/225) were resistant to imipenem and meropenem, respectively. Of the 76 imipenem-resistant P. aeruginosa strains, 45 (59.2%) were positive for MBLs, 34 (75%) strains carried the bla IMP-1 gene, and 1 (2.2%) strain carried the bla VIM - 2 gene.


CONCLUSIONS
Our results showed that there was a high frequency of IMP-1 positive P. aeruginosa in the different wards of the hospitals.
Department of Microbiology, School of Medicine, Kermanshah University of Medical Sciences, Kermanshah, IR Iran.
Ramin
R
Abiri
Medical Biology Research Center, Kermanshah University of Medical Sciences, Kermanshah, IR Iran.
Pantea
P
Mohammadi
Department of Microbiology, School of Medicine, Kermanshah University of Medical Sciences, Kermanshah, IR Iran.
Navid
N
Shavani
Department of Biostatics and Epidemiology, School of Hygiene, Kermanshah University of Medical Sciences, Kermanshah, IR Iran.
Mansour
M
Rezaei
Carbapenems; Polymerase Chain Reaction; Pseudomonas aeruginosa; β-Lactamases