Evolutionary adaptations of Pseudomonas aeruginosa biofilms to combined treatment of ciprofloxacin and an antioxidant in synthetic sputum media

This study examined how antioxidants influence the evolution of ciprofloxacin resistance in Pseudomonas aeruginosa PAO1 biofilms grown in synthetic cystic fibrosis sputum medium (SCFM2). Experimental evolution over six passages showed that resistance developed rapidly under ciprofloxacin alone but was reduced when combined with antioxidants. Whole-genome sequencing revealed distinct mutation profiles between treatments, supporting a role for reactive oxygen species in driving antimicrobial resistance.