Tehran University of Medical Sciences Iranian Journal of Microbiology 2008-3289 15 5 2023 10 12 642 653 Ni Nengah Dwi Fatmawati Department of Clinical Microbiology, Faculty of Medicine, Udayana University, Bali, Indonesia Gede Ngurah Rsi Suwardana Department of Clinical Microbiology, Faculty of Medicine, Udayana University, Bali, Indonesia Ida Ayu Gde Wahyudevi Dharmika Department of Clinical Microbiology, Faculty of Medicine, Udayana University, Bali, Indonesia Ni Made Adi Tarini Department of Clinical Microbiology, Faculty of Medicine, Udayana University, Bali, Indonesia I Nengah Sujaya Department of Public Health and Preventive Medicine, Faculty of Medicine, Udayana University, Bali, Indonesia I Wayan Suranadi Department of Anaesthesiology and Intensive Care, Faculty of Medicine, Udayana University, Bali, Indonesia 2023 06 15 2023 09 05 Background and Objectives: Detecting the source of a potential outbreak of multidrug resistant (MDR) Acinetobacter baumannii is necessary to be investigated. This study aimed to detect the possibility of A. baumannii outbreak in a hospital setting using a combination of random amplified polymorphism DNA- polymerase chain reaction (RAPD-PCR), antibiograms, and the presence of oxacillinase genes. Materials and Methods: The antibiogram of 31 clinical isolates and six environmental isolates of A. baumannii were determined by Vitek® 2 Compact. Oxacillinase genes (OXA-23, -24, -51, and -58) were detected by PCR, and RAPD-PCR was conducted using DAF-4 and ERIC-2 primers. The Similarity Index and dendrogram were generated using GelJ v2.3 software. Results: The antibiograms showed that all MDR A. baumannii isolates has very limited susceptibility to cephalosporins, but mostly susceptible to tigecycline. All isolates were positive for blaOXA-51-like gene, thirty-two of 37 total isolates (86.5%) were positive for blaOXA-23-like gene, and none were positive for blaOXA-24-like and blaOXA-58-like genes. RAPD-PCR showed that the DAF-4 primer on average had more band visualization and lower Similarity Index’s variation compared to the ERIC-2. The discriminatory power of DAF-4 was 0.906. There was a significant correlation between the DAF-4 dendrogram pattern with the antibiogram (r=0.494, p<0.001) and the presence of blaOXA-23-like gene (r=0.634, p<0.001) from all ICU A isolates. Six out of fourteen ICU A isolates belonged to the same cluster with >95% Similarity Index, while one clinical isolate having an identical dendrogram and antibiogram pattern with an environmental isolate within this cluster. Conclusion: There is a high probability of MDR A. baumannii outbreak within ICU A detected by multiple analysis of RAPD-PCR, antibiogram and the blaOXA-23-like gene profiles. This combinatorial approach is conceivable to mitigate possible outbreak situations of A. baumannii in the local hospital without sophisticated microbiology laboratory. https://ijm.tums.ac.ir/index.php/ijm/article/view/4264 https://ijm.tums.ac.ir/index.php/ijm/article/download/4264/1610