Pseudomonas aeruginosa infection becomes chronic in CF lung since bacteria tend to acquire mucoid phenotype and drug-resistant biofilm. New antibiofilm drugs are intensively studied and these researchers have identified in this area the natural protein fragments called Host Defence Peptides (HDPs), which are secreted from all multicellular eukaryotic organisms and represents an essential component of innate immunity. They have developed and optimized a bioinformatics tool that allows the localization of HDP-like sequences hidden (cryptic) in potential HDPs releasing proteins. By this approach, they identified three interesting HDPs (GVF27, IMY47 and HVA36) and now they will carry out experiments on CF Pseudomonas aeruginosa clinical strains, on epithelial bronchial cells and CF murine models; the aim is to verify their antimicrobial potency and antibiofilm properties, when used alone or in synergy with conventional antibiotics.