To investigate the role of sRNA in regulatory mechanisms underlying antibiotic resistance, in murine models of chronic infection sRNA-deleted mutants were subjected to minimum Inhibitory Concentrations (MICs) determination of antibiotics commonly used in the clinical practice and tests for virulence. The results confirmed the role of sRNA in conferring virulence to bacteria. The sRNA ErsA was particularly studied and it was shown that ErsA deletion strongly reduces the virulence of P. aeruginosa in a murine model of chronic infection. This result correlates with the observation that an ErsA-deleted mutant is less pro-inflammatory than the wild-type and induces lower cell death in infected bronchial epithelial cells. The achievements of this project have the potential to foster the development of innovative antimicrobial strategies: using sRNA as novel targets, the effort is to identify drug molecules that can bind and inhibit sRNA functions.