Arezoo Fallah - Immunology Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
Mohammad Ahangarzadeh Rezaee - Immunology Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
Alka Hasani - Infectious and Tropical Diseases Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
Mohammad Hossein Soroush Barhaghi - Department of Microbiology, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
Hossein Samadi Kafil - Drug Applied Research Center, Tabriz University of Medical Sciences, Tabriz, Iran

Objective(s): Acinetobacter baumannii has a high propensity to form biofilm and frequently causes medical device-related infections with multiple-drug-resistance in hospitals. The aim of this work is to study antimicrobial resistance and the role of bap and cpaA genes in biofilm formation by A. baumannii to understand how this pathogen persists in the hospital environment. Materials and Methods: Theantibiotic resistance profile and in vitro biofilm-forming ability of one hundred clinical isolates of A. baumannii was evaluated by disc diffusion and crystal-violet staining methods, respectively. Isolates were tested for the presence of bap and cpaA genes. Results: The isolates were highly resistant to cefepime, third-generation cephalosporins, ciprofloxacin, cotrimoxazole, aminoglycosides and carbapenems. Moreover, four isolates were resistant to colistin. Quantification of biofilm showed that ۴۳% of the isolates were strong biofilm-producer. Furthermore, ۳۲% of the isolates exhibited moderate biofilm-formation and showed initial binding activity. Frequency of bap and cpaA were determined ۹۲% and ۳۶%, respectively. Conclusion: There was strong association between the presence of bap gene and biofilm formation by A. baumannii isolates (P=۰.۰۰۳). In addition, multidrug resistant isolates produced stronger biofilm than other isolates (P=۰.۰۰۰۱). These results indicate importance of biofilm in resistance of isolates and effect of presence of bap gene in biofilm formation by A. baumannii strains.

Acinetobacter baumannii, Antibiotic resistance, Biofilm, Bap, CpaA