Bacterial adhesins (PapG and FimH) (PapG/FimH)

Bacterial adhesins, primarily PapG and FimH, are critical virulence factors located on the tips of fimbriae in uropathogenic Escherichia coli (UPEC) (Howell et al., 2005). These proteins function as lectins, enabling the bacteria to adhere to specific carbohydrate receptors on the surface of uroepithelial cells, which is the essential first step in the pathogenesis of urinary tract infections (UTIs) (Gupta et al., 2007). PapG, found on P-fimbriae, binds to alpha-Gal(1-4)-beta-Gal receptors, while FimH, found on Type 1 fimbriae, binds to mannose-containing receptors (Lavigne et al., 2008). Cranberry proanthocyanidins (PACs), particularly those with unique A-type linkages, exert their therapeutic effect by binding to these adhesins or causing conformational changes that prevent their interaction with host receptors (Foo et al., 2000). This anti-adhesion mechanism effectively inhibits bacterial colonization and biofilm formation without exerting the selective pressure that leads to antibiotic resistance (Ahuja et al., 1998). Consequently, cranberry-derived products are widely used as a prophylactic strategy to reduce the recurrence of UTIs by facilitating the clearance of pathogens through urine flow (Jepson et al., 2012). The efficacy of these compounds is often measured using the urinary anti-adhesion activity (AAA) bioassay, which correlates with the concentration of soluble PACs excreted in the urine (Howell et al., 2010). While generally safe, high consumption of cranberry products may pose risks such as kidney stones due to oxalate content or potential interactions with anticoagulant medications like warfarin.

Other names

P-fimbriae adhesinType 1 fimbriae adhesinUropathogenic Escherichia coli adhesinsFimbrial lectinsPapGFimH

Cranberry proanthocyanidins (PACs) inhibit bacterial adhesion by binding to fimbrial adhesins (e.g., PapG and FimH) on the surface of uropathogenic bacteria, preventing their attachment to host uroepithelial receptors through competitive inhibition and steric hindrance.