Cranberries and probiotics are individually considered as functional foods. This study evaluated
the potential synergy between bioactive proanthocyanidins (c-PAC) derived from
cranberries and probiotics on reducing the invasiveness of extra-intestinal pathogenic Escherichia
coli (ExPEC) in a cell culture model. ExPEC can be a component of the gut microbiota
in healthy individuals, and reducing the invasiveness of ExPEC is a potential means to lessen
the risk of subsequent urinary tract infections (UTI), the most common bacterial infections
in women. c-PAC (>92 % A-type) concentrations greater than 36 g c-PAC/mL significantly
(p < 0.05) reduced ExPEC invasion, and was not inhibited by the presence of probiotics. Scanning
electron microscopy suggests that the mechanism by which c-PAC prevent ExPEC invasion
is by cross-linking surface virulence factors. A probiotic blend also significantly reduced invasion,
albeit via a different mechanism. This study demonstrated the potential benefit of
combining functional A-type c-PAC components in cranberry foods with probiotics.