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

Metallo-β-lactamaseproduction among Gramnegative bacteria, including Pseudomonas aeruginosa, has become a challenge for treatment of infections due to these resistant bacteria. The aim of the current study was to evaluate the metallo-β-lactamaseproduction and carriage of bla-VIM genes among carbapenemresistant P. aeruginosa isolated from burn wound infections. A crosssectional study was conducted from September 2014 to July 2015. One hundred and fifty P. aeruginosa isolates were recovered from 600 patients with burn wound infections treated at ImamMusaKazem Hospital in Isfahan city, Iran. Carbapenemresistant P. aeruginosa isolates were screened by disk diffusion using CLSI guidelines. Metallo-β-lactamaseproducing P. aeruginosa isolates were identified using an imipenem-EDTA double disk synergy test (EDTAIMP DDST). For detection of MBL genes including blaVIM-1 and bla-VIM-2, polymerase chain reaction (PCR) methods and sequencing were used. Among the 150 P. aeruginosa isolates, 144 (96%) were resistant to imipenem by the disk diffusion method, all of which were identified as metallo-β-lactamaseproducing P. aeruginosa isolates by EDTAIMP DDST. Twentyseven (18%) and 8 (5.5%) MBLproducing P. aeruginosa isolates harbored bla-VIM-1 and bla-VIM-2 genes, respectively. Our findings showed a high occurrence of metallo-β-lactamase production among P. aeruginosa isolates in burn patient infections in our region. Also, there are P. aeruginosa isolates carrying the bla-VIM-1 and bla-VIM-2 genes in Isfahan province.