Recurring urinary tract infections (rUTIs) are frequently caused by Escherichia coli, which invades urothelial cells and forms quiescent bacterial reservoirs. D-mannose, an inert monosaccharide, represents a notable agent for rUTI prevention; however, there is no agreement on its dosage. To provide pharmacological basis for an effective dose, we evaluated its ability to inhibit adhesion of E. coli to urothelial cells. E. coli strains isolated from the urine of a woman with recurrent urinary tract infections were selected according to adhesion capacity. Anti-adhesive efficacy and invasion were tested using the TCC-5637 urothelial cell line. The IC50 for the anti-adhesive efficacy and anti-invasion activity of D-mannose were 0.51 mg/ml and 0.30 mg/ml, respectively, both with concentration-dependent inhibition. Lastly, the biofilm interference of D-mannose was evaluated to be 50 mg/ml. D-mannose inhibited the adhesion of E. coli to urothelial cells at high concentrations, whereas inhibition of invasion occurred at much lower concentrations.
Keywords: D-mannose; E. coli; acute cystitis; effective dose; inert monosaccharides; recurrent urinary tract infections.