Proanthocyanidin is commonly used for inhibiting urinary tract infection (UTI) 
of sensitive strains of Escherichia coli. The aim of this study was to 
investigate the effect of proanthocyanidin on adherence of uropathogenic 
multi-drug resistant E. coli to uroepithelial cells, which has not yet been 
investigated so far. Extracts of the purified proanthocyanidin were prepared 
from dried cranberry juice. Purity and structural assignment of proanthocyanidin 
was assessed using high performance liquid chromatography and (13)C nuclear 
magnetic resonance spectroscopy, respectively. Subsequently, its affect on 
multi-drug resistant bacteria as well as quantification of anti-adherence 
bioactivity on human vaginal and bladder epithelial cells was appraised. 
Inhibition of adherence to an extent of about 70% with multi-drug resistant E. 
coli strains was observed on uroepithelial cell. The anti-adherence bioactivity 
of the proanthocyanidin was detected at concentrations of 10-50 µg/ml with 
significant bacteriuria. Probable proanthocyanidin through A-type linkages 
either combines to P-fimbriae of bacterial cells or modifies the structural 
entity of P-fimbriae and inhibits bacterial adherence to uroepithelial cells. 
The proanthocyanidin exhibited anti-adherence property with multi-drug resistant 
strains of uropathogenic P-fimbriated E. coli with in vitro study. Hence 
proanthocyanidin may be considered as an inhibitory agent for multi-drug 
resistant strains of E. coli adherence to uroepithelial cells.