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

Background and Aim : Pseudomonas aeruginosa has recently emerged as one of the main causes of nosocomial infections due to vast antibiotic resistance potency. The production of metallo-β-lactamases (MBLs) is ۱ of the resistance mechanisms in Pseudomonas aeruginosa . : Imipenem is a member of Carbapenem with stability against most t -lactamases.It is of particular use in the treatment of infections associated with drug resistant gram negative bacteria harboring ESBL and AmpC genes. The aim of this study was to determine antimicrobial resistance pattern and the imipenem resistance in Pseudomonas aeruginosa and the presence of metallo- -lactamases (MBLS) in resistant isolates.Methods : In this study, the prevalence of MBL-producing strains was determined among ۵۰ P. aeruginosa isolated from patients inGorgan, Iran. Also, resistance to various antibiotics was determined by disk diffusion test.Minimum inhibitory concentration (MIC) of imipenem was determined for Pseudomonas aeruginosa. Disk diffusion method with disks containing imipenem and imipenem+۱۰µl EDTA (۰.۵ M) was used for determination of the presence of metallo- -lactamases. An increase of ≥۷ mm in the inhibition zone diameter of EDTA containing imipenem disk compared to imipenem disk was considered MBL positive. Results : A high rate of resistance to antibiotics was seen in the ۵۰ strains. Most of the isolates were resistant to, ceftazidime, cefotaxime and tobramycin. ۱۶ isolates (۳۲%) were MDR. Also Among these, MBL activity was detected in ۳ of ۱۹ imipenem-resistant strains. ۱۹ isolates showed MIC≥۸ µg/ml for IPM. Based on the DDST results, ۳ isolates were confirmed to be MBL producers.Conclusion : Carbapenem resistance and production of the metallo-beta-lactamase enzyme in Pseudomonas aeruginosa are increasing According to the presence of metallo - lactamases in bacterial strain in the region, resistance to this valuable therapeutic agent is not unexpected

کلیدواژه ها:

imipenem ، metallo-β-lactamase ، Pseudomonas aeruginosa