Background and Objectives: Carbapenem resistance mediated by metallo beta lactamases (MBL) in Acinetobacter baumannii is a global challenge due to its rapid spread and limited therapeutic options. To determine the prevalence of MBL in A. baumannii isolates in hospitalized patients by both phenotypic and genotypic methods. Materials and Methods: The clinical samples were collected from in patients and subcultured on routine culture media for growth. Identification of bacteria along with antimicrobial sensitivity testing was done by VITEK -2 Compact (bioMerieux). Antibiotics that were not tested by VITEK-2 were tested manually by Kirby-Bauer disk diffusion method according to CLSI 2017 and EUCAST 2016 guidelines. The isolates which were resistant to carbapenem (imipenem and/ or meropenem) were tested by phenotypic (imipenem-EDTA combined disk method) and genotypic method for presence of common metallo beta lactamases genes (blaIMP, blaNDM, blaGIM, blaVIM, blaSPM and blaSIM). Conclusion: The prevalence of MBL in carbapenem resistant isolates of A. baumannii was 87.7%. blaNDM was the most common gene detected. No significant difference was found in the ability of phenotypic and genotypic methods for MBL detection. The resistance rate of the A. baumannii is high for most antibiotics except for polymyxins (E&B) and tigecycline.

Background and Objectives: Carbapenem resistance mediated by metallo beta lactamases (MBL) in Acinetobacter baumannii is a global challenge due to its rapid spread and limited therapeutic options. To determine the prevalence of MBL in A. baumannii isolates in hospitalized patients by both phenotypic and genotypic methods. Materials and Methods: The clinical samples were collected from in patients and subcultured on routine culture media for growth. Identification of bacteria along with antimicrobial sensitivity testing was done by VITEK -2 Compact (bioMerieux). Antibiotics that were not tested by VITEK-2 were tested manually by Kirby-Bauer disk diffusion method according to CLSI 2017 and EUCAST 2016 guidelines. The isolates which were resistant to carbapenem (imipenem and/ or meropenem) were tested by phenotypic (imipenem-EDTA combined disk method) and genotypic method for presence of common metallo beta lactamases genes (blaIMP, blaNDM, blaGIM, blaVIM, blaSPM and blaSIM). Conclusion: The prevalence of MBL in carbapenem resistant isolates of A. baumannii was 87.7%. blaNDM was the most common gene detected. No significant difference was found in the ability of phenotypic and genotypic methods for MBL detection. The resistance rate of the A. baumannii is high for most antibiotics except for polymyxins (E&B) and tigecycline.