Antibacterial and Antibiofilm Effects of Resveratrol and Naringin on Multidrug-Resistant Escherichia coli: Associations with Resistance-Related Gene Expression

Abstract

Background: Multidrug-resistant Escherichia coli represents a significant challenge in antimicrobial therapy because of its ability to acquire resistance mechanisms, form biofilms, and regulate the expression of resistance-associated genes. Plant-derived compounds, including resveratrol and Naringin, have attracted attention as potential antibacterial and antibiofilm agents.Methods: This study investigated the antibacterial, antibiofilm, and gene-expression effects of resveratrol and Naringin against clinical multidrug-resistant E. coli isolates. Antibacterial activity was evaluated using growth inhibition and minimum inhibitory concentration assays. Biofilm formation was assessed using the crystal violet microtiter plate method. The expression levels of the resistance-associated genes marA and acrB were evaluated using quantitative real-time PCR, with recA used as the reference gene.Results: Both resveratrol and Naringin reduced bacterial growth and biofilm formation, with resveratrol showing stronger inhibitory activity under the tested conditions. Treatment was also associated with changes in the expression of the resistance-associated genes marA and acrB. The magnitude and direction of these changes varied according to the tested compound and experimental condition.Conclusion: The findings suggest that resveratrol and naringin may affect both phenotypic bacterial behavior and resistance-associated gene expression in multidrug-resistant E. coli. However, further studies involving larger numbers of isolates, detailed molecular analyses, and in vivo investigations are required to clarify their mechanisms of action and therapeutic potential.