Inhibitory Effect of Silica-Coated Iron Oxide Polymer Nanocomposite Modified with Hibiscus sabdariffa L. extract against Pseudomonas aeruginosa and Staphylococcus aureus with Phenotypic and Genotypic Methods

Abstract Polyvinyl alcohol (PVA) /Hibiscus sabdariffa L. extract containing superparamagnetic iron oxide (Fe3O4@SiO2@Hs@PVA) nanocomposite has been prepared through a facile and cost-effective method. During this procedure, H. sabdariffa L. extract plays a vital role in the modification and biocompatibility of the resultant nanocomposite. The antibacterial effects of nanocomposites against important nosocomial pathogens of Staphylococcus aureus and Pseudomonas aeruginosa were evaluated by disk diffusion and MIC methods. The results showed that the Fe3O4@SiO2@Hs@PVA nanocomposite had higher antibacterial activity than important common antibiotics against Staphylococcus aureus and Pseudomonas aeruginosa pathogens, possibly due to high surface area, smaller size, and lack of development of antibiotic resistance mechanisms. The Fe3O4@SiO2@Hs@PVA nanocomposite study can be used as an adjunctive therapy against pathogens with high antibiotic resistance. Furthermore, the expression of the mexY gene, which is a multidrug antibiotic efflux pump in Pseudomonas aeruginosa, decreased 32-fold under the effect of the nanocomposite, so it is thought that the expression of antibiotic resistance genes could be reduced.