Synergistic inhibition of the urinary tract pathogen Staphylococcus saprophyticus by curcumin and berberine

Abstract

Staphylococcus saprophyticus is a Gram-positive pathogen that is most commonly associated with community-acquired urinary tract infections in adolescent and adult women. While antibiotics can be used to treat these infections, they often reoccur and there has been increased interest in using herbal preparations to treat them. Curcumin has been promoted as a treatment for a variety of diseases, but its effectiveness is limited by its low solubility in aqueous solutions and poor bioavailability. The sensitivity of S. saprophyticus to curcumin and berberine was determined by plate count assays, minimum inhibitory concentrations in microtiter plates, and growth kinetics. When 100 µg ml-1 berberine was combined with 20 µg ml-1 curcumin, there was a large increase in the lag phase and a decrease in the growth rate and final yield of bacteria. There was complete inhibition of growth in normal human urine. These studies indicate that a combination of curcumin with berberine allows curcumin to be used at much lower concentrations.