Combating uropathogenic E. coli: from natural products to new molecular targets

Urinary tract infections (UTI) are one of the world wide infections with immense costs for society. UTI are mostly caused by uropathogenic E. coli (UPEC), specifically adapted to the urogenital system by various virulence factors (adhesins, toxin, iron acquisition system, fitness-motility genes, immune evasion). Systematic investigations of traditionally used medicinal plants indicate antivirulent activity under in vitro and in vivo conditions. Hydroethanolic extracts from Orthosiphon stamineus are strong inhibitors of bacterial adhesion to bladder and kidney cells, due to polymethoxylated flavones. Infection studies in mice indicate comparable effects of the extract (750 mg/kg p.o.) to standard norfloxaxin treatment. The antivirulent effect is due to inhibition of the bacterial chaperon-usher system, leading to impaired formation of the fimbrial structures. Cranberry fruit extract ( Vaccinium macrocarpon ) induces Tamm-Horsfall Protein (THP) in the kidney as shown within a biomedical study in 16 healthy volunteers [ 1 ]. This again leads to inhibition of bacterial adhesion, as THP blocks the mannose-binding side of FimH. Therefore cranberry extract can be assessed as an inductor of innate immune defense. Infusions of Equisetum arvense are strong inductors of THP after 8 days of oral intake in humans besides diuretic effects [ 2 ]. Malonylated dammaranes from Betula sp. interact with the mannose-binding domain of FimH of UPEC, leading to reduced bacterial adhesion and as a counter-reaction to significant increase in bacterial motility. These data support the traditional use of many herbal materials from European Medicine for UTI and synergism indicate that also combinations of herbal materials can have better effects than the individual plants. Publication History Article published online: 05 March 2026 © 2026. Thieme. All rights reserved. Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany