Bacterial strains and growth conditions

The clinical isolate of Pseudomonas aeruginosa, PA14, was used in all experiments. The synthetic cystic fibrosis sputum medium was prepared a described by Palmer et al. [34] except that the concentration of FeSO₄·7H₂O was increased to 100 μM and that of KNO₃ to 100 mM. This was done to allow for increased anaerobic biofilm formation after 96h, which was required for the extraction of sufficient amounts of RNA for subsequent RNA_Seq analysis.