Inhibition of bacterial binding to mouse macrophages by Pseudomonas alginate.

Alginate, an acetylated polymer of D-mannuronic and L-guluronic acid obtained from a mucoid strain of Pseudomonas aeruginosa was shown to inhibit the binding of an isogenic non-mucoid revertant to mouse peritoneal and pulmonary macrophages. Inhibition of bacterial binding by the alginate was also demonstrated in tests with other non-mucoid P. aeruginosa strains and a strain of Staphylococcus albus. Since the mucoid form of P. aeruginosa eventually predominates in chronic P. aeruginosa infection in patients with cystic fibrosis, it is postulated that the alginate's inhibition of binding gives mucoid forms a selective advantage over non-mucoid forms against macrophage defence mechanisms in the lung.