Effects of resveratrol on the urease-positive urinary tract pathogens Staphylococcus saprophyticus and Proteus mirabilis

Abstract

Resveratrol (3, 5, 4’-trihydroxy-Trans-stilbene) is a polyphenolic plant metabolite with antibacterial, antioxidant, and anti-inflammatory activities. Staphylococcus saprophyticus and Proteus mirabilis were inhibited by pure resveratrol with minimum inhibitory concentrations of 250 to 500 µg ml-1. Urease activity in cell-free extracts and whole cells was partially inhibited by resveratrol but a concentration of 5 mmol l-1 was required to reduce it by more than 60%. Inhibition was competitive for S. saprophyticus but noncompetitive for P. mirabilis. Addition of resveratrol to the growth medium did not affect the specific activity of urease or prevent the increase in pH that occurs as a result of urease activity. Resveratrol reduced biofilm formation by S. saprophyticus at concentrations >125 µg ml-1 and partially inhibited it by P. mirabilis in rich media containing urea. While resveratrol has some potential for the treatment of urinary tract infections, it may need to be modified or combined with other urease inhibitors.