Pseudomonas aeruginosa (P.a.) pulmonary infection tends to become chronic in CF. Researchers focus on the hypothesis that viable but non-culturable (VBNC) bacteria are implicated in chronic P.a. infection. VBNC are dormant bacterial forms, which are favoured by pulmonary CF environment. They are difficult to detect since don’t grow in common culture media and therefore need specific molecular techniques. This project aims to investigate the role of antibiotic treatment in the emergence and persistence of VBNC P. aeruginosa forms through the study of in vitro biofilms of P.a.; further to develop non-cultural assays capable of detecting and counting VBNC P.a. cells in patient samples. A more reliable microbiological diagnosis of P.a. infection through the representation of its actual pulmonary colonization, also encompassing dormant forms, is expected; and effective antimicrobial treatments capable of contrasting, or at least containing, the development of biofilm and persistent bacterial forms.