Biofilm formation and Antibiotic resistance of Acinetobacter baumannii strains isolated from clinical samples at hospitals of Zahedan, Iran

Introduction and Objectives: Acinetobacter baumannii is a major cause of nosocomial infections. It has the ability to develop resistance to antibiotics quite easily. Biofilm formation is an important feature of mentioned strains. It is clear from the epidemiologic evidence that related biofilms play a role in infectious diseases. This study was designed to investigate the antibiotic resistance pattern and biofilm formation potency of Acinetobacter baumannii strains.Materials and Methods: Acinetobacter baumannii strains were isolated from thirty different clinical samples obtained from 3 hospitals of Zahedan during January to May 2018. They were identified by staining and biochemical methods as discussed by Bovet and Grimond. Antibiotic resistance pattern of all isolates were checked by disc diffusion test, Kirby Bauer disc diffusion method. Acinetobacter biofilm formation was investigated for 72 hours on glass and polypropylene surfaces in two shaking and stationary conditions.Result: Gentamicin, Tetracycline , Ceftazidim, , Amikacine and Meropenem were used in this experiment and majority (99%) of Acinetobacter baumannii strains were resistant to meropenem and mostly (60%) were sensitive to amikacine. Some isolates were recognized as Multi drug resistant (MDR) A.baumannii. The biofilm formation at the polypropylene surface is greater than that of the glass and in the case of shaking state.Conclusion: During last decades, resistance of A.baumannii to different antibiotics was elevated, according to our experiment and similar researches; it was shown each isolate has stayed susceptible to one or more common antibiotics. A greater understanding of the nature of biofilms and also their role in serious infections will help us in development of new and more effective treatment of nosocomial infections caused by Acinetobacter strains.

Keywords:

Nosocomial infection , Acinetobacter baumannii , antibiotic resistance , CSH , biofilm formation