Detection of Metallo-β-Lactamase Producing Pseudomonas aeruginosa Isolated From Burn Patients in Tehran, Iran

Background: The production of metallo-beta-lactamases (MBLs) is 1 of the resistance mechanisms in Pseudomonas aeruginosa (P. aeruginosa). There is not enough information regarding the prevalence of MBL-producing P. aeruginosa and the type of involved genes in Iran. Methods: In this study, the prevalence of MBL-producing strains was determined among 100 P. aeruginosa isolated from infections in burn patients in Tehran, Iran. An increase of mm in the inhibition zone diameter of EDTA (930 mu g) containing imipenem disk compared to imipenem disk was considered presence of MBL. The polymerase chain reaction (PCR) test was used for the detection of 4 genes encoding MBLs (IMP-1, IMP-2, VIM-1, VIM-2). Also, resistance to various antibiotics was determined by disk diffusion test. Results: A high rate of resistance to antibiotics was seen in the 100 strains. Among these, MBL activity was detected in 65 of 69 imipenem-resistant strains. However, only 13 of these phenotypically positive strains contained the MBL gene VIM-2. No other MBL genes were detected. Conclusion: This study showed for the first time the specific MBL gene present in P. aeruginosa isolated from burn patients in Tehran, Iran.