Role of neuraminidase-dependent adherence in Bacteroides fragilis attachment to human epithelial cells.

Of 50 B. fragilis strains isolated from clinical samples we have demonstrated that 24 (48%) possess an adhesin that mediates a neuraminidase-dependent attachment of B. fragilis to mammalian epithelial cells, but does not mediate any association with human polymorphonuclear leucocytes. This ligand interacts with a mammalian cell receptor that contains a galactoside residue, exposed after neuraminidase pretreatment. Our results suggest a possible role for cell associated neuraminidase in mediating a two step adherence mechanism.