Tehran University of Medical Sciences Iranian Journal of Microbiology 2008-3289 13 3 2021 06 05 282 293 Abolfazl Vahhabi Department of Bacteriology and Virology, Immunology Research Center, School of Medicine, Tabriz University of Medical Sciences, Tabriz, IranImmunology Research Center, School of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran; Department of Bacteriology and Virology, School of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran Alka Hasani Department of Bacteriology and Virology, Immunology Research Center, School of Medicine, Tabriz University of Medical Sciences, Tabriz, IranImmunology Research Center, School of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran; Department of Bacteriology and Virology, School of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran; Clinical Research Development Unit, Sina Educational, Research and Treatment Center, School of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran Mohammad Ahangarzadeh Rezaee Department of Bacteriology and Virology, School of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran Behzad Baradaran Immunology Research Center, School of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran Akbar Hasani Department of Clinical Biochemistry and Laboratory Sciences, School of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran Hossein Samadi Kafil Department of Bacteriology and Virology, School of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran Elgar Soltani Department of Bacteriology and Virology, School of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran; Clinical Research Development Unit, Sina Educational, Research and Treatment Center, School of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran 2021 01 28 2021 05 17 Background and Objectives: Carbapenem treatment for Acinetobacter baumannii‎‎ infections presently faces threats owing to the production of several types of carbapenemase enzymes, prevalence of which varies among different countries. We explored the current trend of antibiotic resistance in A. baumannii clinical isolates from North West Iran, sought the mechanism of carbapenem resistance and addressed the sequence type groups in carbapenem resistant A. baumannii‎‎ (CRAB). Materials and Methods: A. baumannii‎‎ (n=112) isolates were recovered from various clinical specimens of patients admitted in internal, surgery, burn, infectious diseases and various ICUs wards. Genetically confirmed A. baumannii isolates were screened for carbapenem resistance by the Kirby-Bauer and E-test and the presence of blaMBL, blaOXA-like, ISAba1 genes by PCR. Sequence groups were identified by multiplex PCR. Results: Multidrug-resistance (MDR) was a characteristic feature of all A. baumannii isolates. Frequency of oxacillinase genes in combination including blaOXA-51-like/blaOXA-23-like, blaOXA-51-like/blaOXA-24/40-like and blaOXA-51-like/blaOXA-23-like/blaOXA-24/40-like was 82.1%, 36.6% and 25.8% respectively. Blending of oxacillinase and MBL genes was evident in eight blaOXA-23-like positive and 7 blaOXA-24-like positive isolates thereby depicting synchronous etiology of carbapenem resistance. Amongst CRAB isolates, 97.3% contained ISAba1 element and 50.9% belonged to the European clone II. Conclusion: Synchronicity among blaOXA-like with blaMBL and ISAba1 gene was a hallmark of this investigation. Though origin or route of transmission was not elucidated in this study but co-existence among OXA and MBL producing genes is a therapeutic concern demanding strict surveillance strategies and control programs to halt the dissemination of these isolates in the hospital setting. https://ijm.tums.ac.ir/index.php/ijm/article/view/2961 https://ijm.tums.ac.ir/index.php/ijm/article/download/2961/1345