The anti-biofilm and anti-virulence activities of trans-resveratrol and oxyresveratrol against uropathogenic Escherichia coli

Uropathogenic Escherichia coli (UPEC) is the primary causative agent of urinary tract infections, which are one of the most common infectious disease types in humans. UPEC infections involve bacterial cell adhesion to bladder epithelial cells, and UPEC can also form biofilms on indwelling catheters that are often tolerant to common antibiotics. In this study, the anti-biofilm activities of t-stilbene, stilbestrol, t-resveratrol, oxyresveratrol, ε-viniferin, suffruticosol A, and vitisin A were investigated against UPEC. t-Resveratrol, oxyresveratrol, and ε-viniferin, suffruticosol A, and vitisin A significantly inhibited UPEC biofilm formation at subinhibitory concentrations (10-50 μg ml^-1). These findings were supported by observations that t-resveratrol and oxyresveratrol reduced fimbriae production and the swarming motility in UPEC. Furthermore, t-resveratrol and oxyresveratrol markedly diminished the hemagglutinating ability of UPEC, and enhanced UPEC killing by human whole blood. The findings show that t-resveratrol, oxyresveratrol, and resveratrol oligomers warrant further attention as antivirulence strategies against persistent UPEC infections.

Dietary restriction of iron availability attenuates UPEC pathogenesis in a mouse model of urinary tract infection

Iron is a critical nutrient required by hosts and pathogens. Uropathogenic Escherichia coli (UPEC), the principal causative agent of urinary tract infections (UTIs), chelate iron for their survival and persistence. Here, we demonstrate that dietary modulation of iron availability limits UPEC burden in a mouse model of UTI. Mice on a low-iron diet exhibit reduced systemic and bladder mucosal iron availability and harbor significantly lower bacterial burden, concomitant with dampened inflammation. Hepcidin is a master regulator of iron that controls iron-dependent UPEC intracellular growth. Hepcidin-deficient mice ( Hamp1-/-) exhibit accumulation of iron deposits, persistent bacterial burden in the bladder, and a heightened inflammatory response to UTI. However, a low-iron dietary regimen reversed the iron overload and increased bacterial burden phenotypes in Hamp1-/- mice. Thus modulation of iron levels via diet can reduce UPEC infection and persistence, which may have significant implications for clinical management of UTI.