Background and purpose: The prevalence of antibiotic resistant P. aeruginosa strains became a major problem in treatment of burn patients. The aim of this study was to determine the frequency of bla_IMP, bla_VIM and oprD genes among P. aeruginosa isolated from hospitalized burn patients in Tehran Shahid Motahari Hospital, Iran.

Materials and methods: This descriptive study was performed on P. aeruginosa strains isolated from hospitalized burn patients in Shahid Motahari Hospital. Antibiotic resistance phenotypic pattern was evaluated by Kirby Bauer disk diffusion method. The phenotypic investigation of metallo-beta-lactamase (MBL) producers was evaluated by Combined Diffusion Tests Disk (CDDT) method. The prevalence of bla_IMP-1, bla_VIM-1 and oprD genes was investigated by PCR and sequencing methods.

Results: From 100 P. aeruginosa strains, 95 isolates were resistant to imipenem and meropenem which 81 were MBL producing strains. Among all isolates, 13 carried bla_IMP-1 gene, whereas all of strains were negative for bla_VIM-1 gene. In this study we detected two insertion sequence (IS) including ISPpu21 and ISPa1328 among PCR products that were larger than expected.

Conclusion: The P. aeruginosa infections could be prevented and controlled by identification of drug resistance patterns and beta-lactamases.