Abstract

Introduction: Pseudomonas aerouginosa is an important opportunistic pathogen which causes clinical infections among ill patients. Metallo- Beta- lactamases (MBLs) are important mechanisms of carbapenem (drug of choice) resistance among Pseudomonas aerouginosa isolates. The aim of this study was to determine B- lactamases genes (bla-genes) in P. aerouginosa isolates and to detect percentage of MBLs among P. aerouginosa isolates in different wards.

Material and Methods: Clinical isolates of P. aerouginosa in patients hospitalized at Children's Medical Center were collected in two years using a sterile swab. For differentiation and identification of strains the BHI media, Sytrymaid agar and Oxidase test were used and Kirby Baure method antibiotic susceptibility and PCR assay were performed for detection of bla-genes.

Results: Based on the study results from a total of 269 isolates of P. aerouginosa, 39 isolates were found to be imipenem resistant. From these isolates, 19 strains of P. aerouginosa isolates were determined to be MBL producers by phenotypic method. All of the Imipenem resistant P. aerouginosa isolates were examined by PCR for the presence of the bla-genes. All MBL- producing isolates carried bla-IMP Genes. And the results of the antibiogram showed the greatest resistance to the Nitrofurantoin, Nalidixic acid and Cotrimoxazole and Cefixime (100%) and resistance to other antibiotics was also significant.

Conclusion: Considering the prevalence and clinical importance of MBL producing isolates, rapid identification of them and use of the appropriate infection control measures are necessary to prevent further spread of them by these organisms and to help treatment of Infections.

Keywords: P. aerouginosa, metallo-B-lactamases, drug resistance, sytrymaid agar, oxidase test, nitrofurantoin.

Graphical Abstract