Evidence for mucins and sialic acid as receptors for Pseudomonas aeruginosa in the lower respiratory tract.

The nature of the receptors for mucoid and nonmucoid Pseudomonas aeruginosa was investigated by using adherence to injured tracheal epithelium as a model. Bovine submaxillary mucin and crude rat tracheal mucin inhibited the adherence of both types of P. aeruginosa. Among the sugars present in these mucins only N-aceylneuraminic acid inhibited adherence. Inhibition of adherence probably involved the binding of N-acetylneuraminic acid to the bacterial cells and not to the tracheal cells. The mucoid strain appeared to be much more sensitive to inhibition by N-acetylneuraminic acid. Periodate oxidation and cholera filtrate also reduced the adherence of both strains, but Clostridium perfringens neuraminidase treatment did not alter adherence. A nonmucoid isogenic mutant of an unstable mucoid strain was also inhibited by N-acetylneuraminic acid. These data suggest that the receptor for P. aeruginosa is a sialic acid moiety on cell surfaces or in mucins.