Contact Lens Disinfectants

Abstract

Purpose: To investigate the susceptibility of Pseudomonas aeruginosa and Fusarium solani , alone and together, to 4 contact lens disinfecting solutions. Methods: Five P. aeruginosa and one F. solani isolates were used. The following solutions were tested: Complete Moisture Plus (AMO Ireland, Dublin, Ireland), ReNu with MoistureLoc (Bausch & Lomb, Rochester, NY), Opti-Free Express (Alcon Laboratories; Forth Worth, TX), and Oxysept Comfort (AMO Ireland, Dublin, Ireland). The effect of the solutions was assessed on single strains of either P. aeruginosa or F. solani and on a combined inoculum of both. Suspensions of P. aeruginosa and F. solani were made in the solutions (1000000 cfu/ml). After 4, 6, 8, and 24 hours, aliquots of suspension were removed and seeded on Luria-Bertani and Sabouraud agar plates. Results: After 4 hours’ exposure, all the solutions were effective against single strains of P. aeruginosa and F. solani , apart from ReNu with MoistureLoc, which needed 6 hours to kill F. solani , two hours more than recommended. When P. aeruginosa and F. solani were tested together, results varied according to the Pseudomonas strain used. Overall, Opti-Free Express and Oxysept Comfort were always effective against both organisms within the minimum recommended time. Conversely, in two assays, ReNu with MoistureLoc failed to kill P. aeruginosa and F. solani after 4 hours’ exposure and needed 24 hours to eradicate F. solani . Conclusions: Contact lens disinfecting solutions may act differently against P. aeruginosa and F. solani , depending on whether the organisms are tested alone or together. ReNu with MoistureLoc showed reduced fungicidal activity in the presence of both organisms. These results may contribute to explain the recent outbreak of Fusarium keratitis associated with the use of ReNu with MoistureLoc.