Abstract Background: The biosynthesis of nanoparticles utilizing entophytic bacteria has received increasing attention, due to its eco-friendly and cost-effective process. Objective: The aim of this study firstly is to isolate bacterial isolate from agricultural fields having the ability to generate biogenic selenium nanoparticles, to detect the antibacterial efficacy of biogenic selenium nanoparticles (SeNPs) lonely, and the antibacterial effect of the combination (biogenic SeNPs/antibiotics) separately against the bacterial isolates selected from urinary tract inflammation. Materials and Methods: The physical features of biosynthesized selenium nanoparticles (bio-SeNPs) including morphology, size, composition, stability, and external surface were analyzed by using different instruments. The antibacterial activity of bio-SeNPs was determined as minimum inhibitory concentration and minimum bactericidal concentration by applying microdilution assay toward bacterial strains causing urinary tract infections. Results: In this study, a selenium-producing bacterium ( Pantoea agglomerans.S10 ) was detected by implying the 16S rRNA fragment amplification method. Depending on the result of the energy-dispersive X-ray, the chemical composition of obtained nanoparticles consisted of selenium, carbon, and oxygen atoms. In addition, the scanning electron microscope image illustrated the small and spherical nanoparticles at size 24 ± 2 nm. Dynamic light scattering and zeta-potential results exhibited polyscattred bio-SeNPs with an average size of 127 nm and a negative charge of 29.5 ± 1.9 mV, which demonstrated their stability in liquids. Fourier-transform infrared analysis revealed selenium metal coated with biomolecules including carbohydrates and proteins that are responsible for the stability of selenium nanoparticles. Combination of bio-SeNPs/antibiotics exposed a higher antibacterial effect compared to each of bio-SeNPs, antibiotics alone. Conclusion: Considering the biocompatibility of bio-SeNPs, it is suggested that bio-SeNPs be used in pharmaceutical drugs as a combination with antibiotics (amikacin, levofloxacin, and piperacillin). Consequently, this combination is required to increase the antibacterial effect of bio-SeNPs, leading to preventing the emergence of multidrug-resistant bacterial strains that cause urinary tract infections.
Ridha et al. (Thu,) studied this question.