Abstract

AbstractBackground: Increase rate of prevalence of multidrug-resistant Acinetobacter baumannii in burn wound infections make treatment with traditional antibiotics more difficult and leads to severe hospital-acquired infection. Silver nanoparticles (AgNPs) show a broad spectrum antibacterial property with less toxic to mammalian cells. Objective: The aim of this study was to evaluate the anti-bacterial and anti-biofilm activities of AgNPs alone and in combination with cyclic membrane-active peptide (Polymyxin B) against multidrug-resistant Acinetobacter baumannii isolated from burn wound infections.Materials and methods: 45 clinical isolates of Acinetobacter baumannii tested for susceptibility tests by disk diffusion method against 12 antibiotics. The minimum inhibitory concentrations (MICs) of AgNPs and polymyxin B were performed with broth microdilution method, synergistic probability was evaluated with time kill-kinetic assays and Calgary technique applied to study biofilm formation.Results: Membrane-active peptides colistin and polymyxin B were the most active antibiotics against Acinetobacter baumannii with sensitivity of 42 (93.4%) and 38 (84.4%) respectively, while cephalosporins (Cefotaxime) and fluoroquinolones (Ciprofloxacin) antibiotics were most resistances antibiotics with 38 (84.5%) and 35 (77.8%) resistances respectively. The data of present study indicated that the distribution of burn patients infected with Acinetobacter baumannii were prevalence significantly among young age groups of 15-29 years old and male / female ratio 0. 64/1. AgNPs display excellent antibacterial activity against multidrug-resistant Acinetobacter baumannii with MIC 2.1. µg/ml ± 0.3 comparing with polymyxin B as standard control with MIC 0.53 µg/ml ± 0.1. The concentration of sub-MIC (½MIC) of AgNPs exhibited bacteriostatic activity against multidrug-resistant Acinetobacter baumannii, while combination of ½ MIC with (½) MIC of polymyxin B display bactericidal effect and complete reductions of Acinetobacter baumannii after 24 h. AgNPs exhibit strong anti-biofilm formation activity with inhibition of biofilm formation about 19 – 24 % at sub-MIC concentration. Moreover, combination of AgNPs with polymyxin B displayed remarkable synergistic anti-biofilm formation with 72 % inhibition of biofilm. Conclusions: The data of this study indicate a strong synergistic anti-bacterial and anti-biofilm activity of combination of AgNPs with membrane-active peptide (Polymyxin B) against multidrug-resistant Acinetobacter baumannii isolated from burn wound infections. These results propose that AgNPs promising novel antimicrobial agent in the clinic.

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The article was added to IASJ on 2018-10-23

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