The effects and mechanisms of aqueous Persicaria capitata extract on uropathogenic Escherichia coli adhesion.

Background: Urinary tract infections (UTIs) in humans are common, with uropathogenic Escherichia coli (UPEC) being the primary pathogen. The adhesive capabilities of UPEC are a substantial pathogenicity factor. Due to limitations of first-line antibiotics, Persicaria capitata (Buch.-Ham. ex D. Don) H. Gross, a traditional Chinese medicinal plant, is frequently used to treat various urological disorders. However, its mechanism regarding bacterial adhesion, remain unclear.

Purpose: To investigate the effects and mechanisms of action of aqueous P. capitata extracts (PCE) on UPEC adhesion in T24 cells and rat models.

Methods: Broth microdilution and growth experiments were used to explore the direct antibacterial effects of PCE on UPEC. Additionally, motility assays were conducted. Different microscopy methods were used to further examine the mechanisms of action. Transcriptomic analysis and RT-qPCR were used to explore mechanisms on a molecular level. Relevant molecules were assessed using western blotting and immunohistochemistry.

Results: PCE modulated UPEC motility by disrupting the fimbriae and flagella. UPEC pathways, including those essential for constructing fimbriae and flagella, and bacterial motility, were affected. PCE reduced UPEC adhesion and invasion of T24 cells, altering the protein expression of adhesion-related molecules, by modulating the secretion of extracellular vesicles (EVs). It improved blood and urine parameters, reduced inflammatory markers, and ameliorated pathological changes in the kidneys and bladder of rats. Furthermore, the expression of adhesion-related molecules in bladder tissues decreased in the UTI rat model.

Conclusions: This study provides new insights into the mechanisms of herbal medicines in treating UTIs.