Synthesis, characterization and biological applications of green synthesized Se NPs using locally isolated multidrug-resistant Escherichia coli

Multidrug-resistant Escherichia coli is a leading cause of nosocomial infections globally. The current study aimed to isolate and detect multidrug-resistant E. coli for use in the extracellular biosynthesis of selenium nanoparticles (Se NPs) as well as investigate they roles in antibacterial and antioxidant applications. Vitek 2 was utilized to confirm the species-level identification of the chosen bacterial isolate after it had been identified classically. Different spectroscopy and microscopy analyses were used to characterize the biosynthesized nanoparticles (NPs) such as UV–visible spectroscopy, FTIR, TEM and Zeta analysis. The adsorption peak for Se NPs was observed at 348 nm which confirmed the successful biogenesis of Se NPs. The presence of proteins linked to NPs that serve as capping and stabilizing agents is indicated by the FTIR spectra. NPs were spherically shaped, negatively charged particles (+48.2 mV) that had an average size of ≈100 nm, assist to their stability. Se NPs demonstrated strong antibacterial activity against Gram positive bacteria (Bacillus cereus, Staphylococcus aureus), and Gram-negative bacteria (Proteus mirabilis, E. coli) in a dose-dependent way. The antioxidant potential of Se NPs was also evaluated compared to ascorbic acid which indicated their distinguished behavior as antioxidants. This study proposes Se NPs as safe, effective, and feasible substitute for treating some pathogenic bacterial strains as well as good antioxidants, suggesting that this green synthesis of Se NPs could provide promising medical applications.