Exopolysaccharide Psl of Pseudomonas aeruginosa (Psl)

Exopolysaccharide Psl is a neutral, branched polysaccharide composed primarily of mannose, rhamnose, and glucose, produced by Pseudomonas aeruginosa through the psl gene locus. Psl is a key structural component of the bacterial biofilm matrix, where it scaffolds cells together, mediates cell–cell and cell–surface adhesion, and provides protection against antimicrobials, host immune effectors, and environmental stresses. Its expression is environmentally regulated and varies between strains, with Psl-dominant and Pel-dominant strains recognized among laboratory and clinical isolates. Psl also plays a role in signaling processes that regulate biofilm gene expression and contributes to the chronicity and resilience of P. aeruginosa infections, particularly in cystic fibrosis airways and on medical devices. Targeting Psl is being explored for novel anti-biofilm therapeutics, but no clinically approved direct inhibitors exist to date.

Other names

Psl polysaccharidePsl exopolysaccharidePolysaccharide synthesis locus exopolysaccharide

Disruption or inhibition of Psl biosynthesis reduces biofilm integrity and bacterial adherence, making bacteria more susceptible to immune clearance and antibiotics. Surfactant-based or polysaccharide-targeting agents can disrupt the Psl matrix, promoting biofilm dispersion.