Author/Authors :
azizi, omid kerman university of medical sciences - department of microbiology and virology, ايران , shahcheraghi, fereshteh pasteur institute of iran - department of bacteriology, ايران , salimizand, himen kurdistan university of medical sciences - department of microbiology and virology, ايران , modarresi, farzan jahrom university of medical sciences - school of medicine - department of microbiology, ايران , shakibaie, mohammad reza kerman university of medical sciences - environmental health sciences and engineering research center, research center for infectious diseases and tropical medicine - department of microbiology and virology, ايران , mansouri, shahla kerman university of medical sciences - department of microbiology and virology, ايران , ramazanzadeh, rashid kurdistan university of medical sciences - cellular molecular research center, faculty of medicine - microbiology department, ايران , badmasti, farzad pasteur institute of iran - department of bacteriology, ايران , nikbin, vajihe pasteur institute of iran - department of bacteriology, ايران
Abstract :
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 biofilmassociated 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. KR080550.1). 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 23 (35.4%), 18 (27.7%), 13 (20%), and 11 (16.9%) of the isolates had strong, moderate, weak, and no biofilm activities, respectively. ompA and csuE genes were detected in all, while bap and blaPER-1 were detected in 43 (66%) and 42 (64%) of the isolates that showed strong and moderate biofilm activities (p ≤ 0.05), respectively. Analysis of bap expression by rqRT-PCR revealed five isolates with fourfold bap overexpression in the presence of low iron concentration (20 μM). Conclusion: The results suggest that bap overexpression may influence biofilm formation in presence of low iron concentration.
Keywords :
Acinetobacter baumannii , Biofilm , Biofilm , associated Protein (bap) , Iron , rqRT , PCR
