Antimicrobial Efficacy of Tea Tree Oil Against Pseudomonas aeruginosa in Contact Lenses

PURPOSE: To evaluate the antibacterial and antibiofilm activity of tea tree oil (TTO) against a multidrug-resistant (MDR) Pseudomonas aeruginosa isolate, used as a representative model of the primary pathogen associated with contact lens-related keratitis. METHOD: TTO was tested for minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), and time-kill kinetics against P. aeruginosa . Biofilm (BF) formation and eradication assays were conducted using crystal violet (CV) and MTT viability tests on biofilms grown on CL surfaces. Cytotoxicity was evaluated in vitro using murine cone photoreceptor cells (661W). RESULTS: TTO showed strong antibacterial activity against MDR P. aeruginosa , with MIC and MBC values of 3.5 and 7 mg/mL, respectively. It inhibited biofilm formation and eradicated mature biofilms on silicone hydrogel contact lenses, outperforming commercial multipurpose solutions ( P