Evaluation of Metallo-β-Lactamase-Production and Carriage of bla-VIM Genes in Pseudomonas aeruginosa Isolated from Burn Wound Infections in Isfahan

Abstract

Background: Metallo-β-lactamase-production among gram negative bacteria, including Pseudomonas aeruginosa, has become a challenge for treatment of infections due to these resistant bacteria. Objectives: The purpose of the current study was to evaluate the metallo-β-lactamase-production and carriage of bla-VIM genes among carbapenem-resistant Pseu-domonas aeruginosa isolated from burn wound infections. Patients and Methods: A cross-sectional study was conducted from September 2014 to July 2015. 150 Pseudomonas aeruginosa isolates were recovered from 600 patients with burn wound infections treated at Imam-Musa-Kazem hospital in Isfahan. Carbapenem-resistant Pseudomonas aeruginosa isolates were screened by disk diffusion using CLSI guidelines. Metallo-β-lactamase-producing Pseudomonas aeruginosa isolates were identified using an imipenem-EDTA double disk synergy test (EDTA-IMP DDST). For detection of MBL genes including bla-VIM-1 and bla-VIM-2, PCR methods and sequencing were used. Results: Among the 150 Pseudomonas aeruginosa isolates, 144 (96%) were resistant to imipenem by the disk diffusion method, all of which were identified as metallo-β-lactamase-producing Pseudomonas aeruginosa isolates by EDTA-IMP DDST. 27 (18%) and 8 (5.5%) MBL-producing Pseudomonas aeruginosa isolates harbored bla-VIM-1 and