SIRT1 mediated autophagy enhancement by Lactobacillus fermentum derived oligosaccharides accelerates wound healing in biofilm associated infection

The present study explores the structural elucidation, antimicrobial properties, and wound-healing potential of a novel oligosaccharide, OligoF, derived from Lactobacillus fermentum. Structural analysis using paper chromatography, and 1D & 2D NMR spectroscopy indicated that OligoF is a linear tetrasaccharide comprising β-D-glucose, α-L-rhamnose, and D-glucuronic acid in a defined sequence. This structural elucidation was further confirmed by key chemical shifts, coupling constants, and glycosidic linkage assignments. OligoF exhibited potent antibacterial activity against multidrug-resistant Pseudomonas aeruginosa isolates, demonstrating inhibition zones of 60-63 mm, a minimum inhibitory concentration (MIC) of 16 µg/mL, and a minimum bactericidal concentration (MBC) of 32 µg/mL. Biofilm eradication assays revealed a significant reduction in biofilm viability by ~ four-fold at sub-MIC concentrations, as evidenced by scanning electron microscopy. OligoF-treated biofilms displayed notable disruption of extracellular matrix and severe bacterial cell distortion compared to untreated controls. In vivo wound-healing assays in rats showed that OligoF significantly reduced wound area and enhanced skin repair compared to untreated controls. Treatment with OligoF notably increased the concentration and gene expression of SIRT1 as well as upregulated the gene expression of beclin1 and ATG5 which are critical regulators of autophagy and cellular repair processes. Histopathological analysis corroborated these findings, revealing enhanced re-epithelialization, granulation tissue formation, and vascularized connective tissue deposition in OligoF-treated wounds. These findings underscore the potential of OligoF as a multifunctional agent with antibacterial and wound-healing properties, paving the way for its application in managing multidrug-resistant infections and promoting tissue repair.