The evaluation of the antibiotic activity of sultamicillin-colistin eluting noisome nanoparticles against biofilm of Acinetobacter isolates.

Background and Aim : Acinetobacter baumannii is a multi-drug resistant bacterial pathogen causing nosocomial outbreaks worldwide. The particular ability of this pathogen is to form biofilms that demonstrate greater protection against antibiotics, host immune defense, and adverse environmental conditions than the free-living cells. The purpose of this study was to evaluate the antibiofilm activity of sultamicillin-colistin eluting noisome nanoparticles against biofilm of Acinetobacter isolates. Methods : In this study, ۴۰ pre-isolated strains were used. Niosomes were prepared using thin-film hydration method and were characterized by zeta potential measurement and Field Emission Electron Microscope (FE-SEM). The release rate of sultamicillin and colistin from the niosome was evaluated using the dialysis method. The Sultamicillin and colistin entrapment efficiency were determined. antibiofilm activity of sultamicillin-loaded niosomes, colistin-loaded niosomes, and sultamicillin-colistin-loaded niosomes was determined using crystal violet method . The MIC of niosomes was determined using the agar diffusion method. Results : The round-shaped sultamicillin-colistin-loaded niosomes were ۲۳۰ nm and had -۲۵mV zeta potential. The percentage of sultamicillin and colistin encapsulation in the niosomes was ۹۱% and ۹۴%,respectively. Release of the sultamicillin and colistin from niosomes occurred over a longer period of time than the non-niosome form. The sultamicillin-colistin containing niosomes removed ۱, ۳, and ۵ day old biofilms at the concentration of ۰.۰۰۶۲۵ µg ml-۱, ۰.۰۳۱۲۵ µg ml-۱, and ۰.۰۶۲۵ µg ml-۱, respectively. The MIC of colistin loaded niosomes and sultamicillin-colistin loaded niosomes were ۰.۵ mg ml-۱ , and ۰.۲۵ mg ml-۱,respectively.however,sultamicillin-loaded niosomes didn’t show antibacterial activity. Conclusion : Niosome nanoparticles containing sultamicillin-colistin could be considered as a promising candidate for the treatment of biofilm-mediated infections of A.baumannii.