4.2. Microorganism and Culture Conditions

Pseudomonas fluorescens AR 11 was purchased by DSMZ (Braunschweig, Germany). Although the fact that is considered less virulent than P. aeruginosa, P. fluorescens is known to have functional traits, able to cause human infections and contamination of equipment associated with intravenous infusion [32,33].

Bacterial cells were grown in a sterile M9 minimal medium supplemented with succinic acid (4 g/L) and made of the following ingredients: NaHPO₄ (6.8 g/L)_, KH₂PO₄ (3 g/L), NaCl (0.5 g/L), NH₄Cl (1 g/L), MgSO₄·7H₂O (95 mg/mL), CaCl₂·2H₂O (5.85 mg/mL) and oligo-elements solution (consisting in 0.198 g/mL EDTA, 2 mg/mL FeCl_3·6 H₂O, 0.21 mg/mL ZnCl₂, 0.03 mg/mL CuCl₂·2 H₂O, 0.025 mg/mL CoCl₂·2H₂O, 0.025 mg/mL H₃BO₃ and 0.004 mg/mL MnCl₂·4 H₂O) at pH 7. Bacterial cells were cultivated at 30 °C in shaking conditions (90 rpm, Minitron Infron HT, Switzerland) overnight. The obtained bacterial suspensions were diluted to have an OD_600nm ≈ 0.5 to be used as inoculum.