Antibiotic resistance and frequency of class 1 integrons among Pseudomonas aeruginosa, isolated from burn patients in Guilan, Iran

BACKGROUND AND OBJECTIVES Antibiotic resistance of Pseudomonas aeruginosa remains a major problem in burn patients. The main objective of this study was to determine the antibiotic resistance pattern and frequency of class 1 integrons among P. aeruginosa strains isolated from patients with burn wound infections in a new Burn Centre in Guilan, Iran. MATERIALS AND METHODS The bacterial isolates were collected from 182 patients with burn wound infections and P. aeruginosa species were identified by standard bacteriological methods. The drug susceptibility test, using 11 antimicrobial agents, was performed for all the isolates via agar disk diffusion method. PCR was carried out for the detection of integrons. RESULTS Out of a total of 182 hospitalized patients in the burn center assessed, 86 (47%) found to have P. aeruginosa in their isolates. Resistance rates to various antibiotics were as follows: cloxacillin (91.8%), cotrimoxazole (86%), cephazolin (83.7%), carbenicillin (74.4%), piperacillin (69.9%), ceftazidime (68.8%), ciprofloxacin (66.3%), tobramycin (58.2%), amikacin (48.8%) and gentamicin (37.2%), while the most effective antibiotic was imipenem with a resistance rate of 23.3%. Thirty nine (45.3%) isolates were detected as multi-drug resistant. The PCR results showed that 37 (43%) P. aeruginosa isolates and 27 (69.2%) multi-drug resistant strains harbored class 1 integrons. A significant correlation was obtained between the presence of integrons and resistance against imipenem, ceftazidime, piperacillin and ciprofloxacin (P <0.001). CONCLUSION Optimization of using antimicrobial agents and control of infection is recommended to prevent the increasing population of drug resistant organisms in the new burn centre setting in this study. Furthermore, the high frequency of class 1 integrons among multi-drug resistant strains might be responsible for dissemination of antibiotic resistance gene.