Evaluation of Antibacterial Activity of Iron Oxide Nanoparticles against Staphylococcus aureus

Biofilm is important virulence factor play an essential role in bacterial pathogenicity through trigger antimicrobial agents. Nanoparticles have antimicrobial properties and the antimicrobial activity depend on nanoparticles size and concentration. This study demonstrated the antimicrobial activity of iron oxide nanoparticle against Gram-positive bacteria within 20 hours. The particles obtained had an average diameter 25 nm; the particles were used to inhibit Staphylococcus aureus biofilm on polystyrene surface. The bacteria were added in 96-well plates to incubate with iron oxide nanoparticles and without iron oxide nanoparticles as control. The biofilm was measured using the safranin staining method that showed variable results depending on bacterial species. However, It was seen that exposure of cells to iron oxide particles showed increased biofilm formation on polystyrene plates. The highest augmentation was recorded for S. Aureus in a concentration of 0.5mg/ml and approaching (78.8 %) highly significant p0.05 and the augmentation was not achieved in a concentration of 50 mg/ml p0.05, The augmentation of S. Aureus in a concentration of 5mg/ml gave (75.8 %). Our result indicated that iron oxide nanoparticles have not antibiofilm activity against bacteria cells within 20 hours for S aureus except at concentration 50mg/ml for S. aureus gave (18.2 %) inhibition rate. The IONPs efficacy depends on the incubation time, bacterial strain and nanoparticles concentration.