Saeedeh ebrahimi - Department of Bacteriology and Virology, Faculty of Medicine, Isfahan University of Medical Science, Isfahan, Iran
Behnam sisakhtpour - Department of Bacteriology and Virology, Faculty of Medicine, Isfahan University of Medical Science, Isfahan, Iran
Sharareh moghim - Department of Bacteriology and Virology, Faculty of Medicine, Isfahan University of Medical Science, Isfahan, Iran
Arezoo mirzaei - Department of Bacteriology and Virology, Faculty of Medicine, Isfahan University of Medical Science, Isfahan, Iran
Vajihe Karbasizadeh - Department of Bacteriology and Virology, Faculty of Medicine, Isfahan University of Medical Science, Isfahan, Iran

Introduction and Objectives: Biofilm-associated infections caused by Acinetobacter baumannii are extremely tenacious to antibiotic treatment. According to this fact, phage therapy is a good choice for alternative treatment. The aim of this study is to investigate the phage effect on A. baumannii biofilm formation. Materials and Methods: The clinical bacteria that isolated were confirmed by phenotypic and PCR method with bla oxa gene, then among of them MDR isolates with disk diffusion method, chose for further investigation. The MIC method was performed accroding to CLSI 2018. Biofilm formation was measured by microtitre plate. Phage isolation from the environment was performed. Finally, the effect of phage was tested on the biofilm formation of A. baumannii by co–incubation. Results: Fifteen MDR isolates detect and in the MIC test, demonstrate the high resistance value, also in the biofilm formation assay 60%, 26.6% and 13.3% of isolates show strong, moderate and weak biofilm formation respectively. among of those isolates one isolate, that has strongest biofilm and the most resistance, choose for the effect of phage in MoI 10, 1, 0.1, 0.01, 0.001. our study demonstrates that the phage in MoI 0.01 has the best effect on the biofilm formation of that bacteria. Conclusion: Our study demostrate that phage in MoI 0.01 could be effective in eradication of biofilm formation in Acinetobacter baumannii. Efficient bacteriolytic activity and significant reduction of the bacterial biofilm suggests its therapeutic potential to be used to treat infection caused by A. baumannii.

multi-drug resistant Acinetobacter baumannii, biofilm, phage, phage therapy