Ratio of A-type to B-type Proanthocyanidin Interflavan Bonds Affects Extra-intestinal Pathogenic Escherichia coli Invasion of Gut Epithelial Cells

Gut colonization by extra-intestinal pathogenic Escherichia coli (ExPEC) increases the risk of subsequent infections, including urinary tract infection and septicemia. Previous work suggests that cranberry proanthocyanidins (PAC) interact with bacterial surface factors, altering bacterial interaction with host cells. Methods were developed to determine if ratios of A-type to B-type interflavan bonds in PAC affect ExPEC agglutination and invasion of enterocytes. In cranberries, 94.5% of PAC contain one or more A-type bonds, whereas in apples, 88.3% of PAC contain exclusively B-type bonds. Results show that cranberry A-type PAC have greater bioactivity than apple B-type PAC for increasing ExPEC agglutination and decreasing ExPEC epithelial cell invasion.