Determination of the prevalence of metallo-β-lactamases producing Pseudomonas aeruginosa strains from clinical samples by imipenem-EDTA combination disk method in Mottahari and Emam Khomaini hospitals of Urmia

Introduction: Pseudomonas aeruginosa is one of the major bacterial nosocomial infections. Metallo-β-lactamases (MBLs) are one of the most important agents for resistance against carbapenem. Based on the role of carbapenem for Pseudomonas infection treatment, in this research clinical strains of MBL producing bacteria were studied. Methods: Fifty Pseudomonas aeruginosa isolated from clinical samples were collected from patients that referred to the Emam Khomeini and Mottahari hospitals of Urmia. After bacterial confirmation with standard bacteriologic tests, bacterial sensitivity was assayed against ten common antibiotics by the method of disk diffusion test. Then imipenem-resistant strains were candidate for the identification of MBL production by imipenem-EDTA (Ethylenediamine tetra acetic acid ) combination disk test. Results: Of all 50 isolated Pseudomonas aeruginosa, 36 isolates (72%) were resistant against imipenem. Obtained results from imipenem-EDTA combined disk test showed that 32.36 isolates (88.9%) had MBL. Conclusion: Although Pseudomonas aeruginosa producing MBL are resistant against all of β-lactams antibiotics, but determining the strains that produce MBL can help physicians to select the suitable antibiotic for treatment and improve the prognosis of the infection due to this bacterium. Keywords: Imipenem-EDTA combination disk test, Metallo-β-lactamase, Pseudomonas aeruginosa, Urmi