Unravelling the antibacterial potential of biosynthesized selenium nanoparticles against Salmonella Typhimurium food pathogen: in vitro and in vivo investigation

OBJECTIVE: It is highly required to find novel alternatives to the antibiotics currently used due to the increasing dissemination of antibiotic resistance among bacteria, especially enteric bacteria. The current study aimed to produce selenium nanoparticles (SeNPs) by Euphorbia milii Des Moul leaves extract (EME). MATERIALS AND METHODS: The produced SeNPs were characterized using different techniques. After that, in vitro and in vivo antibacterial activity against Salmonella typhimurium was elucidated. Moreover, phytochemical identification and quantification of the chemical compositions of EME were performed using HPLC. The broth microdilution method determined the minimum inhibitory concentrations (MICs). RESULTS: The MIC values of SeNPs ranged from 128 to 512 mu g/mL. Additionally, the impact of SeNPs on membrane integrity and permeability was investigated. A marked decline in the membrane integrity and inner and outer membrane permeability was noticed in 50%, 46.15%, and 50% of the tested bacteria, respectively. Subsequently, a gastrointestinal tract infection model was used to study the in vivo antibacterial potential of SeNPs. Remarkably, treatment with SeNPs resulted in average-sized intestinal villi and colonic mucosa in the small intestine and caecum, respectively. In addition, it was revealed there was no inflammation or dysplasia in the studied tissues. SeNPs also enhanced the survival rate and significantly decreased the number of colony-forming units per gram tissues in the small intestine and caecum. Concerning the inflammatory markers, SeNPs significantly (p < 0.05) decreased interleukins (6 and 1 beta). CONCLUSIONS: The biosynthesized SeNPs revealed antibacterial potential in vivo and in vitro; however, this finding should be elucidated clinically in the future.