Tehran University of Medical Sciences Journal of Medical Bacteriology 2251-8649 12 3 2024 08 21 27 34 Lakshmi K Sathyanesan Department of Microbiology, Jubilee Mission Medical College, Thrissur, Kerala India. Rosmi Jose JUBILEE MISSION MEDICAL COLLEGE & RESEARCH INSTITUTE , THRISSUR, KERALA Chithra Valsan Department of Microbiology, Jubilee Mission Medical College, Thrissur, Kerala India. Liji Maria Joy Department of Microbiology, Jubilee Mission Medical College, Thrissur, Kerala, India. 2024 05 27 2024 06 22 Background:   The multidrug-resistant and carbapenem-resistant Acinetobacter baumannii strains are an increasing global concern. The primary cause of carbapenem resistance in A. baumannii is production of various beta-lactamases with versatile hydrolytic capacities. The present study investigates the prevalence of different carbapenemases among clinical isolates of carbapenem-resistant A. baumannii from a tertiary care teaching hospital in Kerala, India. Methods:   Non-duplicate isolates from sputum, endotracheal aspirate, pus, urine, and blood samples were included in the study. Isolate identification and antibiotic susceptibility testing of the isolates were done using vitek 2 system. A conventional polymerase chain reaction  was used to detect the carbapenemase-encoding genes in the isolates. Results:   A total of the 126 isolates studied, among these 105 (83.3%) isolates were from intensive care unit patients and 21(16.6%) were from non-ICU inpatients. Most of the isolates were obtained from respiratory specimens-78(61.9%) followed by pus-33(26.2%), urine-12(9.5%) and blood- 3(2.4%).  The prevalence of carbapenemase genes were as follows:blaOXA-51(n=126, 100%) blaOXA-23 (n=98, 77.7%), blaOXA-58 (n=7, 5.6%), blaNDM (n=66, 52.4%), blaIMP (n=26, 20.6%), and blaVIM (n=20, 15.9%). Among the total isolates 78 (61.9%) isolates harbored metallo-beta-lactamase genes, 47(37.3%) isolates harboured a single carbapenemase gene, while 69(54.8%) isolates harbored two or more genes. Conclusion:   This study reveals a higher prevalence of metallo-beta lactamases and the co-occurrence of multiple carbapenemase genes in Carbapenem resistant A. baumannii isolates. https://jmb.tums.ac.ir/index.php/jmb/article/view/523