Pseudomonas aeruginosa biofilms cause severe</p><p>infections in the airways of patients suffering from cystic</p><p>fibrosis (CF) that are difficult to eradicate, even with</p><p>intensive antibiotic therapy. The main goal of this study</p><p>was to define the dual transcriptional response</p><p>associated with the formation of P. aeruginosa biofilms</p><p>in a polarized lung epithelium monolayer. We analyzed</p><p>the dual response of healthy and CF epithelium after</p><p>infection with P. aeruginosa isolates from sporadic and</p><p>chronic infections. Our results show that chronic</p><p>strains of P. aeruginosa specifically use type I and type</p><p>III secretion systems to hijack the host response.</p><p>Conversely, sporadic strains use ABC transporters to</p><p>counteract the antimicrobial response. In return, there</p><p>is a distinctive expression pattern in CF epithelium,</p><p>including a high degree of cytokine secretion and</p><p>keratinization, largely observed in sporadic infections.</p><p>Our results show that both host and pathogen genomic</p><p>backgrounds contribute to the outcome of infection and</p><p>specific transcriptional signatures could be used in the</p><p>diagnosis, more relevantly in CF patients.