Isolation, Antibiotic Resistance Pattern and Prevalence of Metallo-Beta Lactamase Genes in Pseudomonas aeruginosa Isolates Collected from Patients in Zabol Hospitals1391-92

Pseudomonas aeruginosa has a major role in development of nosocomial infections. Infections caused by P.aeruginosa and dissemination of metallo-beta-lactamases (MBL) have been reported with increasing frequency through-out the world.The aim of this study was to investigate the antibiotic susceptibility and identification of blaIMP-1, blaVIM-1 and blaSPM-1 in P. aeruginosa isolates collected from clinical samples in Zabol, Iran. In this cross-sectional study, 527 clinical samples were cultured and P. aeruginosa isolates was identified by conventional biochemical test. The antimicrobial susceptibility was tested by disk diffusion (Kirby-Bauer) method and MBL producing strains were identified by double-disk synergy test (DDST). From genotypical point of view the presence of blaIMP-1, blaVIM-1 and blaSPM-1 genes was confirmed by PCRusing specific primers. Of 527 clinical samples, 160 isolates (30%) were identified as P. aeruginosa. The resistance rates: imipenem, ciprofloxacin, ceftazidime, cefixime, tobramycin, piperacillin and polymyxin Bwere 14%, 9%, 19%, 98%, 4%, 13% and 13% respectively.DDS test showed that of 22 resistant isolates to imipenem 10 (45%) were MBL producing. We found 10 MBL producing strains by PCR, 100% had VIM gene, 80% carried IMP gene and 80% had both VIM and IMP genes. None of the isolates hadSPM gene. The results showed that, in contrary to the results of studies conducted in other parts of Iran˒ MBL producing isolates had the declining trend in studied area and the frequency of VIM gene is higher than IMP gene.