The increase in antibiotic resistance and the obstacles in producing new antibiotics stimulate the search for alternative anti-infectious strategies. Among these, antivirulence therapies against microbes and toxins’ genes may play an important role. Virulence and antibiotic resistance are regulated by small fragments of RNA (sRNA) produced by bacteria themselves. This study follows FFC#13/2015 and FFC#14/2016 projects, in which researchers extensively investigated the Pseudomonas aeruginosa’ (Pa) sRNA called ErsA. They found that if ErsA is mutated, multidrug-resistant strains of Pa lose virulence and regain sensitivity to major antibiotics. The main objective of the current project is to develop and test anti-ErsA molecules, namely Peptide Nucleic Acids (PNA), and their ability to block ErsA. PNAs have the potential to be new highly specific antibacterial drugs, to be used alone or in combination with other antibiotics in the treatment of Pa lung infections.