Omid Azizi - Department of Microbiology and Virology, Kerman University of Medical Sciences, Kerman, Iran
Fereshteh Shahcheraghi - Department of Bacteriology, Pasteur institute of Iran, Tehran, Iran
Himen Salimizand - Department of Microbiology and Virology, Kurdistan University of Medical Sciences, Kurdistan, Iran
Farzan Modarresi - Department of Microbiology, School of Medicine, Jahrom University of Medical Sciences, Jahrom, Iran
Mohammad Reza Shakibaie - Department of Microbiology and Virology, Kerman University of Medical Sciences, Kerman, Iran - Environmental Health Sciences and Engineering Research Center; Kerman University of Medical Sciences, Kerman, Iran - Research Center for Infectious Diseases and
Shahla Mansouri - Department of Microbiology and Virology, Kerman University of Medical Sciences, Kerman, Iran
Rashid Ramazanzadeh - Department of Bacteriology, Pasteur institute of Iran, Tehran, Iran - Cellular & Molecular Research Center and Microbiology Department, Faculty of Medicine, Kurdistan University of Medical Sciences, Iran
Farzad Badmasti - Department of Bacteriology, Pasteur institute of Iran, Tehran, Iran
Vajihe Nikbin

Background: Acinetobacter baumannii is commonly resistant to nearly all antibiotics due to presence of antibiotic resistance genes and biofilm formation. In this study we determined the presence of certain antibiotic-resistance genes associated with biofilm production and the influence of low iron concentration on expression of the biofilm-associated protein gene (bap) in development of biofilm among multi-drug-resistant A. baumannii (MDRAB). Methods: Sixty-five MDRAB isolates from clinical samples were collected. Molecular typing was carried out by random amplified polymorphism DNA polymerase chain reaction (RAPD-PCR). Biofilm formation was assayed by the microtiter method. Results: The sequence of bap was determined and deposited in the GenBank database (accession no. KR۰۸۰۵۵۰.۱). Expression of bap in the presence of low iron was analyzed by relative quantitative real time PCR (rqRT-PCR). Nearly half of the isolates belonged to RAPD-types A and B remaining were either small clusters or singleton. The results of biofilm formation revealed that ۲۳ (۳۵.۴%), ۱۸ (۲۷.۷%), ۱۳ (۲۰%), and ۱۱ (۱۶.۹%) of the isolates had strong, moderate, weak, and no biofilm activities, respectively. ompA and csuE genes were detected in all, while bap and blaPER-۱ were detected in ۴۳ (۶۶%) and ۴۲ (۶۴%) of the isolates that showed strong and moderate biofilm activities (p ≤ ۰.۰۵), respectively. Analysis of bap expression by rqRT-PCR revealed five isolates with four-fold bap overexpression in the presence of low iron concentration (۲۰ μM). Conclusion: The results suggest that bap overexpression may influence biofilm formation in presence of low iron concentration.

Acinetobacter baumannii, Biofilm, Biofilm-associated Protein (bap), Iron, rqRT-PCR