Tehran University of Medical Sciences Iranian Journal of Microbiology 2008-3289 14 5 2022 10 22 705 711 Keyvan Esmaeili-Fard-Barzegar Department of Bacteriology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran Shahin Najar-Peerayeh Department of Bacteriology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran Ramin Mazaheri Nezhad Fard Department of Pathobiology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran Bita Bakhshi Department of Bacteriology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran 2022 04 26 2022 07 28 Background and Objectives: Acinetobacter baumannii (A. baumannii), an opportunistic pathogen, has been isolated from sewage, soil, and hospital wards. The prevalence of multidrug-resistance A. baumannii has seriously caused a health crisis in hospital settings. Bacteriophages have been used as an alternative therapy for control carbapenem-resistant bacteria-caused infections. We aimed to assay lytic effect of a filamentous phage on clinical bacterial strains. Materials and Methods: 500-ml water samples was collected from sewage in Tehran. Sewage samples were precipitated at 6000 rpm for 10 minutes and filtered using 0.45-µm syringe filters. Bacteriophage was isolated using double-layer agar assay and evaluated its stability at various pH and temperature ranges. In addition, the stability of the phage was assayed at chloroform 0.1%. Results: Transmission electron microscopy imagine showed phage is filamentous called vB-AbaI-TMU2. The phage affected on its own host so that could not effect on any Pseudomonas aeruginosa and Klebsiella pneumoniae strains. vB-AbaI-TMU2 phage was stable at pH 5 and 7 and also temperatures 25 and 37°C. vB-AbaI-TMU2 was stable at chloroform 0.1%. vB-AbaI-TMU2 phage infected carbapenem-resistant A. baumannii strains while other bacterial strains were resistant to. Conclusion: The present study indicated the isolated phage had a narrow host range and is susceptible to various pH values and temperatures. https://ijm.tums.ac.ir/index.php/ijm/article/view/3677 https://ijm.tums.ac.ir/index.php/ijm/article/download/3677/1509