Antiadhesive Molecules in Milk and Berries against Respiratory Pathogens

Bacterial attachment to host mucosal tissues is the essential first step in microbial colonization and pathogenesis. The strategy behind antiadhesive agents is to block the adhesion of pathogen to the host cells. Since this reduces the reservoir of bacteria in the human population, it may diminish the frequency of carriers and ultimately reduce the prevalence of bacterial infections. Thus, antiadhesives hold the potential for preventing infectious diseases. This is important since new methods are needed due to shortcomings of effective vaccines and increasing antibiotic resistance. In the present study, the binding and inhibitory activity of milk, berries and juices were investigated against meningitisand respiratory infection-associated bacteria. The binding of Neisseria meningitidis pili to bovine thyroglobulin was clearly inhibited by human milk neutral and bovine milk acidic oligosaccharides in a microtiter well assay. In cell culture experiments and the microtiter well assay, inhibitory and binding activity with N. meningitidis were detected for those bilberry, cranberry, lingonberry, and crowberry fractions which contained anthocyanins or a mixture of proanthocyanidins and flavonols. Streptococcus pneumoniae cells bound most extensively to the low-molecular size fraction of cranberry juice and Streptococcus agalactiae cells to the highmolecular size fraction of cranberry. Hemagglutination induced by Streptococcus suis was most effectively inhibited by the middle-molecular size fraction of cranberry. In conclusion, it has been possible to identify several previously unknown binding and inhibitory sources which impair bacterial adherence; their activities depend on both the natural component and the bacterial species. These results indicate that neutral human milk oligosaccharides and acidic bovine milk oligosaccharides possess potential value in the development of functional foods or drugs against meningococcal infections and furthermore, berry material, especially from the Vaccinium species, may be able to inhibit the attachment of N. meningitidis, S. pneumoniae, S. agalactiae, and S. suis to epithelial cells. However, clinical trials will be needed to confirm these in vitro results. National Library of Medicine Classification: QW 52, QU 75, QU 220, QU 83, WB 430, WB 428, WC 245, WC 217 Medical Subject Headings: Bacterial Adhesion; Fimbriae, Bacterial; Milk; Oligosaccharides; Fruit; Vaccinium myrtillus; Vaccinium macrocarpon; Vaccinium vitis-idaea; Flavonoids; Anthocyanins; Proanthocyanidins; Flavonols; Meningococcal Infections; Neisseria; Pneumococcal Infections; Streptococcus; Hemagglutination; Cells, Cultured; In Vitro