Sialyl-Le(x) and sulfo-sialyl-Le(x) determinants are receptors for P. aeruginosa.

Pseudomonas aeruginosa, the main pathogen in the airways of patients suffering from cystic fibrosis (CF), binds to carbohydrate chains of respiratory mucins. Using flow cytometry and polyacrylamide based fluorescent glycoconjugates, it was previously demonstrated that several strains of P. aeruginosa recognize a set of neutral and acidic carbohydrate epitopes found at the periphery of respiratory mucins, especially sialyl-Le(x). This structure, overexpressed in mucins from CF patients, could be responsible in part for the persistence of lung infection in CF patients. The aim of the present work was to determine whether a glycoconjugate bearing the 6-sulfo-sialyl-Le(x) epitope, also found in abundance in CF airway mucins, is also preferentially recognised by different strains of P. aeruginosa. The study was conducted with a nonpiliated strain 1244-NP and four mucoid strains isolated from CF patients. For four strains out of five, the affinity for 6-sulfo-sialyl-Le(x) was as high as for sialyl-Le(x) derivative. These results were confirmed for strain 1244-NP by a microtiter plate assay.