Determination of Drug resistance patterns and detection of bla-VIM gene in Pseudomonas aeruginosa strains Isolated from burned patients in the Emam Mosa Kazem hospital, Esfahan, Iran (2008-9)

Background and abjectives: Pseudomonas aeruginosa is the most common cause of burn wound infections in many centers. This bacterium shows high resistance to majority of antibiotics including β-lactams. The frequency of beta-lactam resistant P.aeruginosa is increasing in many countries due to production of Metallo beta lactamase enzymes. The aim of this study was to determine the antibiotic resistance patterns ofPseudomonas aeruginosa isolated from burn wound infections and to identify bla-VIM gene by application of phenotypic and genotypic methods. 79 isolates of Pseudomonas aeruginosa were recovered from 111 burn patients using microbiological methods. For all the isolates, antibiotic susceptibility tests were performed by Kirby–Bauer disc diffusion method. All imipenem resistant isolates were screened for MBLs production by IPMEDTA disk and in order to detect blaVIM gene, PCR analysis was performed. Resistance rate of the isolated strains were as fallows: imipenem 94.9% pipracilin 97.4% ciprofloxacin 98.7% tobramycin 95% ceftazidim and ticarcilin 100%. IPM-EDTA disk method showed that 41 out of 74 (55.4%) of imipenem resistant isolates of P. aeruginosa, were metallo-β-lactamase producers.The PCR method showed that 34 out of 79 P. aeruginosa isolates were positive for blaVIM. The results demonstrated that incidence of MBLs producing Pseudomonas aeruginosa in burn patients is higher than expected. Therefore detection of antibiotic resistance patterns of bacteria as well as detection of MBLs enzyme producing isolates are of great importance in prevention and control of these infections.