BACKGROUND AND OBJECTIVES One of the main invasive bacteria found in wound and burn infections, which has become more resistant to antibiotics than other bacteria, is Acinetobacter baumannii. MATERIALS AND METHODS 30 strains of Acinetobacter baumannii were isolated from the wounds of patients from the hospitals of East Azarbaijan province. For all strains, the antibiogram test was performed with 15 different antibiotics, and 26 strains with multiple antibiotic resistance were selected for bacteriophage isolation against. Bacteriophage was isolated against Acinetobacter baumannii isolates using agay by-layer method. Then, the host range of bacteriophages was determined and phages with the widest host range were selected for more characterization. One step growth curve was determined and the stability of bacteriophages was evaluated in the environmental conditions (pH, UV and temperature). RESULTS AND DISCUSSION Based on the obtained results, one of the isolated bacteriophages had lytic effect against 15 bacterial isolates. A cocktail of four isolated phages showed lytic effect on 23 of 30 isolates. Based on one step growth curves, latent period of the phages was evaluated 20-60 min. According to the stability experiments, the selected bacteriophages maintained their activity in UV exposure up to 10 minutes. They were stable at pH value of 6-10 and temperature 4-60 ℃. Examination of these bacteriophages by electron microscopy (TEM) showed that these bacteriophages were belonged to the Tectiviridae and Podoviridae families. CONCLUSION This study showed that phage therapy can be an effective alternative to fight antibioticresistant infections caused by Acinetobacter baumannii.
