The efficacy of povidone-iodine, hydrogen peroxide and a chemical multipurpose contact lens care system against Pseudomonas aeruginosa on various lens case surfaces

Purpose: To determine the antimicrobial efficacy of a povidone-iodine system (PVP-I; cleadew, OPHTECS Corporation, Kobe, Japan), a peroxide system (AOSEPT Plus with HydraGlyde, Alcon, Fort Worth, TX), and a chemical multipurpose system (renu fresh, Bausch & Lomb, Rochester, NY) on contact lens case surfaces that are both in contact and not in contact with the solutions during lens disinfection. Methods: The surfaces of the inner walls, underside of the lid, and lens holder (if applicable) of the cases were inoculated with P. aeruginosa ATCC 27853. The cases were disinfected with the solutions as per their manufacturer instructions. After disinfection, the inoculated surfaces were swabbed and the amount of surviving P. aeruginosa was determined. Following this experiment, separate cases were inoculated and disinfected as before. This time the cases were agitated after recommended disinfection time and the amount of P. aeruginosa in the disinfecting solution was quantified immediately, and again after resting for 7 days. Experiments were conducted in triplicate (n = 3). Results: Units are expressed in log CFU. All three solutions significantly reduced P. aeruginosa on direct-contact surfaces (all p < 0.039). On non-contact surfaces, the reduction of P. aeruginosa in the PVP-I system (pre-disinfection: 6.8 +/- 0.5, post-disinfection: 1.0 +/- 0.0; p < 0.001) was significant, but not for the hydrogen peroxide system (pre-disinfection: 6.3 +/- 0.6, post 5.5 +/- 0.5; p = 0.194) and the chemical multipurpose system (predisinfection: 6.6 +/- 0.1, post-disinfection: 5.6 +/- 0.8; p = 0.336). After 7 days post-disinfection, no P. aeruginosa regrowth was observed in the PVP-I system (Day 1: 1.0 +/- 0.0, Day 7: 1.0 +/- 0.0; p = 1) and the chemical multipurpose system (Day 1: 4.2 +/- 0.2, Day 7: 1.8 +/- 0.9; p = 0.012), however regrowth was observed in the hydrogen peroxide system (Day 1: 3.4 +/- 0.6, Day 7: 6.1 +/- 0.4; p = 0.003). Conclusion: The PVP-I system was more effective against P. aeruginosa on non-contact surfaces than the hydrogen peroxide system or the chemical multipurpose system and is capable of inhibiting regrowth of P. aeruginosa for at least 7 days post-disinfection.

Automated summary

All three solutions significantly reduced P. aeruginosa on direct-contact surfaces. The PVP-I system was more effective against P. aeruginosa on non-contact surfaces than the hydrogen peroxide system or the chemical multipurpose system, and capable of inhibiting regrowth of P. aeruginosa for at least 7 days post-disinfection.