[Myth or truth. Cranberry juice for prophylaxis and treatment of recurrent urinary tract infection].
Recurrent urinary tract infections are a frequent problem in urological practice. Long-term antibiotic prophylaxis can cause resistance of some intestinal bacteria, and after therapy is stopped, infections often resume. In controlled studies, general recommendations for prophylaxis were shown to inhibit reinfection. One of these recommendations is the consumption of cranberries. A review of the literature in PubMed as well as the recently published Cochrane database systematic review confirmed that daily consumption of cranberries prevents recurrent urinary tract infections. In vitro studies have shown that binding of the P fimbriae of Escherichia coli to the uroepithelial tissue can be inhibited in the presence of proanthocyanidins, the active ingredient of cranberries. In clinical studies, the evidence is not so pronounced. Many other bacteria have fimbriae, but only a few subpopulations have P fimbriae. P fimbriae are frequent in E. coli, so this adhesion can be prevented. However, in a subanalysis of randomized and controlled studies, it was shown that women with recurrent urinary tract infections might profit from consuming cranberries.