Blocking of Pseudomonas aeruginosa and Ralstonia solanacearum Lectins by plant and microbial branched polysaccharides used as food additives.

Pseudomonas aeruginosa antibiotic resistance prompted the search for glycodecoys that would block its lectin-dependent adhesion to human cells. We have used the lectins of this pathogen, PA-IL (galactophilic LecA) and PA-IIL (fucophilic LecB), and two additional pathogenic bacterial lectins, CV-IIL (fucophilic, of Chromobacterium violaceum) and RS-IIL (mannophilic, of Ralstonia solanacearum), for assaying the pathogenic lectin-blocking abilities of some plant and microbial polysaccharidic food additives, adding the mannophilic plant lectin Con A as a reference. Locust-bean and guar galactomannans and acacia gum very strongly inhibited PA-IL. The other lectins, excluding CV-IIL, were very strongly inhibited by yeast mannan. Xanthan and inulin were weak inhibitors. The differential blocking of these lectins by galactosylated branches of plant polysaccharides and by mannan matched their inhibition by avian egg whites, human milk, and royal jelly (protecting animal embryos and neonates from infections). The nondigestability and nontoxicity of the food additives are advantageous for curing gastrointestinal and external infections.