DOI: 10.12688/f1000research.176668.2 ISSN: 2046-1402

Evaluation of the Antibiofilm and Antimicrobial Effects of Selenium Nanoparticles on Multidrug-Resistant Salmonella Isolates

Shaimaa Noori Mahal, Hamza Jabbar Jabour, Asmaa Samir Mohsin, Sura Mouaid Abbas, Noor M.Taher
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Background and Aim Salmonella is a major cause of bloodstream infections and foodborne diseases worldwide. The rise of multidrug-resistant (MDR) strains and biofilm formation complicates treatment and public health management. This study aimed to evaluate the effects of biosynthesized selenium nanoparticles (SeNPs) on the biofilm-associated gene expression of MDR Salmonella isolates. Methods Thirty-two Salmonella isolates were recovered from blood samples in Baghdad, Iraq. Biofilm formation was assessed using Congo Red and microtiter plate assays. Antimicrobial susceptibility testing was performed for multiple antibiotics. SeNPs were biosynthesized and characterized using scanning electron microscopy (SEM) and applied at fractional MIC concentrations (12.5%, 25%, 50%, and 100%) for three representative MDR, strong biofilm-forming isolates. RT-qPCR was conducted to quantify the expression of biofilm-associated genes csgD and ssrB , using gapA as a housekeeping gene . Results All isolates formed biofilms, with 75% classified as strong formers. MIC values for SeNPs were determined for the selected isolates. RT-qPCR analysis revealed a dose-dependent downregulation of csgD expression, reaching statistical significance at all tested SeNP concentrations, whereas ssrB expression exhibited a non-significant decreasing trend. Higher SeNP concentrations resulted in stronger suppression of csgD . Conclusions Biosynthesized SeNPs exhibited in vitro modulatory effects on biofilm-associated gene expression in MDR isolates. These findings provide preliminary evidence of a potential antibiofilm regulatory effect, while direct antibacterial activity and in vivo efficacy require further investigation.

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