The human opportunistic pathogen Pseudomonas aeruginosa (PA) is responsible for chronic infections of the respiratory epithelium in cystic fibrosis patients. PA takes advantage of an arsenal of virulence factors to infect and colonize human lungs. Among them, the lectin LecA favours epithelium invasion by interacting with host cell globotriaosylceramide (Gb3). A new therapeutic approach is based on the development of synthetic multivalent molecules (glycoclusters) targeting LecA with a higher affinity than its natural ligand. Atomic force microscopy-single cell force spectroscopy has been used to study the effect of glycoclusters on the bacteria-cell interaction. Glycoclusters have been shown to affect the detachment work and detachment force of the bacteria-cell interaction. The specificity and the efficiency of the glycocluster in targeting the lectin and destabilizing the PA-epithelial cell adhesion are demonstrated and discussed.