Antibacterial and antibiofilm activity of bismuth oxide nanoparticles produced by Bacillus subtilis against clinical Pseudomonas aeruginosa isolated from wound infections

Background & The biological method of nanoparticles synthesis by microorganisms has a special place due to its high environmental compatibility and reduced energy consumption and costs. The aim of this study was to determine the effect of bismuth oxide nanoparticles produced by green methods on bacteria causing hospital infections. Materials & In this study, 160 samples were collected from burn wound infections in patients hospitalized in Motahari Burn Rescue Hospital. Resistant strains were identified phenotypically and genotypically. Synthesis of bismuth oxide nanoparticles by Bacillus subtilis wild type strain. The synthesis of bismuth oxide nanoparticles was confirmed by infrared spectroscopy, X-ray diffraction, and scanning electron microscopy. Finally, the antibacterial activity of nanoparticles against isolated strains was investigated with the standard disk diffusion test. Biosynthesis of nanoparticles showed an average size of 44 nm using Bacillus subtilis. All 44% (71 strains) of Pseudomonas aeruginosa formed a biofilm. Bismuth oxide nanoparticles at a concentration of 2000 ppm were inhibited 5% of Pseudomonas aeruginosa. By increasing the concentration of bismuth oxide nanoparticles, its inhibitory effect increased. The results showed that there is a significant difference between the groups exposed nanoparticle and ciprofloxacin.