Abstract:

Background and Aim: The aim of this study was determination the prevalence of Klebsiella pneumonia carbapenamase (KPC) and Metallo-β-lactamases (MBL) genes among P. aeruginosa isolates from cystic fibrosis (CF) and burn patients.

Materials and Methods: This descriptive study was carried on the 70 and 30 isolates of P. aeruginosa from wound of burn patients of Shahid Motahari hospital and sputum of CF patients of Mofid Pediatric hospital of Tehran during 2013, respectively. Antibiotic susceptibility test (AST) and minimal inhibitory concentration (MIC) by microdilution both were performed based on CLSI guidelines. Combination Disk Diffusion Test (CDDT) and Modified Hodge Test (MHT) detected MBL and KPC production, respectively. PCR and further sequencing determined frequency of IMP, VIM and KPC genes.

Results: Resistant profile of P. aeruginosa isolates from wound of burn and sputum of CF patients to tested antibiotics by AST were as follow: 60 (85.71%) vs. 1 (3.3%) to imipenem, 58 (82.85%) vs. 11 (36.6%) to meropenem, (81.67%) vs. 13 (43.3%) to gentamicin, 56 (79.32%) vs. 8 (26.6%) to aztreonam, 56 (79.32%) vs. 5 (16.6%) ciprofloxacin, 55 (78.21%) vs. 5 (16.6%) to cefepime, 54 (77.12%) vs. 10 (33.3%) to ceftazidime, 52 (74.15%) vs. 3 (10%) to piperacillin.  By CDDT, (13/30) 43.3% and (46/70) 51.42% of CF and burn P. aeruginosa isolates were MBL producer, respectively. No P. aeruginosa was identified as KPC-producer by MHT. The prevalence of IMP, VIM and KPC genes among bacterial isolates of burn patients were 7(10%), 0 (0%) and 0 (0%). None of the mentioned genes were detected among CF isolates.

Conclusion: Because of the high incidence of MBL P. aeruginosa producer among both burn and CF patients, MBL and carbapenemase identification is important for prevention strategies of infections.