67 Golnar Rahimzadeh 1 , Sasan Sarli 2 , Mohammad Ahanjan 3* 1. Pediatric Infectious Diseases Research Center, Communicable Diseases Institute, Mazandaran University of Medical Sciences, Sari, Iran. 2. Student Research Committee, Faculty of Medicine, Mazandaran University of Medical Sciences, Sari, Iran. 3. Department of Microbiology, Molecular and Cellular Biology Research Center, Faculty of Medicine, Mazandaran University of Medical Sciences, Sari, Iran. * Corresponding Author: Mohammad Ahanjan, Associate Professor. Address: Pediatric Infectious Diseases Research Center, Communicable Diseases Institute, Mazandaran University of Medical Sciences, Sari, Iran. Phone: +98 (911) 3546204 E-mail: ahanjan2007@gmail.com Prevalence of β-lactamase-encoding Genes in Isolated Acinetobacter baumannii From Clinical Samples in Sari, Iran Background: The prevalence of Acinetobacter baumannii as a causative agent of hospital-acquired infections, particularly in burn units and intensive care units, is a major concern due to its innate and acquired resistance to several antibiotics. The presence of beta-lactamase-encoding genes in this bacterium has made it resistant to carbapenems as the last-resort antibiotics for treating infections caused by A. baumannii. This study aims to determine the prevalence of β-lactamase-encoding genes and antibiotic resistance of A. baumannii isolates from burn patients in northern Iran. Materials and Methods: In this descriptive cross-sectional study, A. baumannii isolates were obtained from clinical samples of patients in Zare Burn Hospital in Sari City, from 2013 to 2015. The isolates’ antibiotic sensitivity was determined using the disk diffusion method. To investigate the prevalence of β-lactamase genes (blaVIM, blaIMP, and INT), the PCR test was conducted. Results: Of 150 patients, 54.7% were men and 45.3% were women. The highest resistance rates were against ceftazidime, cefepime, meropenem, imipenem, ciprofloxacin, amikacin, gentamicin, and colistin in order. It was observed that 31% of the isolates produced metallo-β-lactamase enzyme. The genes blaVIM, blaIMP, and INT were detected in 35%, 45%, and 60% of the isolates, respectively. Conclusion: A. baumannii isolates have significant resistance to cephalosporins and carbapenems. It is recommended to avoid the irrational prescription of cephalosporins and carbapenems for infections caused by A. baumannii. A B S T R A C T Keywords: Nosocomial infections, Multiple drug resistance, β-lactamases, Metallo-β- lactamases, Acinetobacter baumannii Citation Rahimzadeh G, Sarli S, Ahanjan M. Prevalence of β-lactamase-encoding Genes in Isolated Acinetobacter bau- mannii From Clinical Samples in Sari, Iran. Research in Molecular Medicine. 2023; 11(1):67-72. https://doi.org/10.32598/ rmm.11.1.1292.1 https://doi.org/10.32598/rmm.11.1.1292.1 Use your device to scan and read the article online Article info: Received: Revised: Accepted: Article Type: Research Paper Copyright © 2024 The Author(s); This is an open access article distributed under the terms of the Creative Commons Attribution License (CC-By-NC: https://creativecommons.org/licenses/by-nc/4.0/legalcode.en), which permits use, distribution, and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes. 16 Feb 2024 01 Jan 2024 28 Jan 2024