Literature Review: Cranberry in Preventive Medicine—A Herbal Approach to Recurrent Urinary Tract Infections ^†

Abstract

Introduction: Urinary tract infections (UTIs) represent a growing health challenge, due to the rise of antimicrobial resistance (AMR) in common pathogens. Bacteria such as Escherichia coli, responsible for 80% of cases, and Pseudomonas aeruginosa, an opportunistic pathogen of concern, have developed effective virulence mechanisms. These mechanisms include the use of adhesins, such as type 1 and P fimbriae, to attach to uroepithelial cells, and the formation of biofilms, which protect bacteria from immune system and antibiotics, favoring recurrent infections. Methodology: This study is an integrative review based on articles published until 2015, identified in PubMed, Scopus, and Google Scholar using specific keywords. The inclusion criteria considered clinical relevance and the main findings. Results: In this context, cranberry (Vaccinium macrocarpon) emerges as a complementary strategy for the prevention and treatment of UTIs. The fruit is rich in bioactive compounds, particularly type A proanthocyanidins (PACs). The main action of PACs is to inhibit the adhesion of uropathogenic bacteria to the walls of the urinary tract, an effect that extends to type 1 and P fimbriae, which are resistant to other inhibitors. Additionally, studies show that PACs can interfere with quorum sensing, a cellular communication system bacteria use to coordinate biofilm formation. Conclusions: By disrupting this process, cranberries make pathogens more vulnerable to the action of the immune system and medications, possibly controlling the inflammatory response associated with the infection. Clinical evidence, although not always statistically significant, suggests a reduced risk of symptomatic UTIs with consumption of cranberry extract.