Binding of type-III group-B streptococci to buccal epithelial cells.

A binding assay was used to study the attachment of type-III group-B streptococci (GBS) to buccal epithelial cells. Results indicate that an adhesin, with the characteristics of a protein, is the molecule at the streptococcal cell surface responsible for attachment to the buccal cells. The bacterial adhesin probably recognises a sugar on the surface of the mucosal cell, because periodate oxidation of the buccal cells caused a significant reduction in subsequent adherence of GBS. A sonicate to type-III GBS blocked the binding of the organism to buccal cells. The effects of physical and chemical modifications of the sonicate on its ability to prevent bacterial attachment are described; these corroborate the evidence gained from heat and periodate treatments of the buccal cells and GBS. Results suggest a lectin type of attachment mechanism for type-III BGS which can be blocked by N-acetyl-D-glucosamine, rather than attachment by means of a lipoteichoic acid as described for group-A streptococci.