Inhibition of Pseudomonas aeruginosa and Escherichia coli O157:H7 Biofilm Formation by Plant Metabolite ε-Viniferin

Pathogenic biofilms are associated with persistent infection due to their high resistances to diverse antibiotics. Pseudomonas aeruginosa infects plants, animals, and humans and is a major cause of nosocomial diseases in patients with cystic fibrosis. In the present study, the antibiofilm abilities of 522 plant extracts against P. aeruginosa PA14 were examined. Three Cares plant extracts at a concentration of 200 mu g/mL inhibited P. aeruginosa biofilm formation by >80% without affecting planktonic cell growth. In the most active extract of Cares pumila, resveratrol dimer epsilon-viniferin was one of the main antibiofilm compounds against P. aeruginosa. Interestingly, epsilon-viniferin at 10 mu g/mL inhibited biofilm formation of enterohemorrhagic Escherichia coli O157:H7 by 98%. Although Carex extracts and trans-resveratrol are known to possess antimicrobial activity, this study is the first to report that C. pumila extract and epsilon-viniferin have antibiofilm activity against P. aeruginosa and E. coli O157:H7.