The Fe3O4 nanoparticles functionalized by glutamic acid and conjugated with thiosemicarbazide decreases the expression of icaA and icaD biofilm genes in methicillin-resistant Staphylococcus aureus isolates

Abstract

Biofilm production is an important survival strategy to increase resistance against antimicrobial agents. The icaA and icaD genes have been ascribed to play active roles for biofilm formation in methicillin-resistant Staphylococcus aureus (MRSA). Therefore, preventing the expression of these genes is one of the most powerful strategies to control biofilm production. Today, nanoparticles offer a novel potential alternative for fighting resistant bacteria. Here, we have synthesized Fe3O4 magnetic nanoparticles (MNPs) that are functionalized by glutamic acid and conjugated with thiosemicarbazide using a chemical co-precipitation method and studied their effect on the biofilm-forming ability of MRSA.Diffuse Reflectance Spectroscopy (DRS), Fourier transform infrared spectroscopy (FTIR), scanning and transmission electron microscopy, Zeta potential analysis, Dynamic light scattering (DLS), energy dispersive X-Ray spectroscopy (EDS), and X-ray diffraction (XRD) used for validation and chemical characterization of synthesized nanoparticles.The obtained results confirmed the solution stability, good dispersion, and spherical/cubic morphology of Fe3O4@Glu–TSC MNPs with an average size of 35–60 nm. Minimum inhibitory concentration values of functionalized MNPs were reduced by two folds against each respected strain in comparison with the Fe3O4 MNPs (alone). Furthermore, the quantitative PCR data analysis showed a decrease in the expression of icaA and icaD genes in the presence of Fe3O4@Glu–TSC MNPs, up to 50% that was associated with a reduction of biofilm formation compared to control.The Fe3O4@Glu–TSC MNPs can be considered as a new inhibitor of biofilm production in antibiotic-resistant bacteria.