Detection of VIM and IMP-type Carbapenemases genes in Pseudomonas aeruginosa isolates of hospitalized patients in two hospitals in Iran

Background: Beta-lactam antibiotics resistance specifically imipenem and meropenem, the last choices of treatment, causes fatal events in patients with Pseudomonas aeruginosa infection. The aim of this study was to detect the IMP and VIM metallo-beta-lactamase genes in 103 isolates of P. aeruginosa in two Iranian hospitals.Methods: In this study, we evaluated the susceptibility of P. aeruginosa to a range of B-lactam antibiotics using disk diffusion method as a standard biochemical test.Using conventional PCR method, we evaluated VIM and IMP alleles of metallo-betalactamase (MBL) genes in 103 isolates of P. aeruginosa. Result: The mean age of the patients was 49.98± 22.84 years (Min=1y, Max=88y) and 55.7% of them were female. The high to low degrees of resistance to antibiotics were observed in turn for imipenem, meropenem, ticarcillin, ceftazidime, cefepime and Piperacillin. The frequency of MBL- Producing P. aeruginosa was 19(18.4%). Using PCR method, we detected the VIM and IMP genes in 6 (5.8%) and 2(1.9%) of all isolates, respectively. Among 26 imipenem and meropenem-resistant strains (25.2%), 18 cases (69.2%) were MBL producing and VIM was detected in 19% of them. Conclusion: Evaluation of these carbepenemases genes improve epidemiologic researches and also, can be used as a diagnostic tool for discriminating betweenantibiotics resistant and non-resistant strains of P. aeruginosa as well as follow-up the patients after treatment.

Keywords:

IMP , VIM , Metallo-Beta-Lactamase , Pseudomonas Aeruginosa