In Vitro Antimicrobial Efficacy of Silver Lens Cases Used With a Multipurpose Disinfecting Solution

PURPOSE: We evaluate the in vitro antibacterial activity of silver-copolymerized barrel cases compared to nonsilver barrel cases in combination with a multipurpose disinfecting solution (MPDS). METHODS: The ability of silver and nonsilver cases to reduce the number of adherent Gram-positive and Gram-negative bacteria was assessed. Additionally, the efficacy of silver cases along with MPDS was investigated in the presence of organic soil and contact lenses. Contact lens cases were challenged with 10(6) colony-forming units (CFU)/mL of five bacterial species. Adherent bacteria were dislodged from lens cases and surviving organisms enumerated. RESULTS: Significantly lower numbers of microbes were recovered from silver cases compared to controls, for all bacterial strains (P < 0.005). The combination of silver case along with MPDS showed added efficacy against Gram-positive and -negative bacteria with a maximum reduction of 3.00 ± 0.5 Log(10) CFU/mL, compared to the efficacy of silver cases alone (1.97 ± 0.4 Log(10) CFU/mL). The addition of organic soil and a contact lens resulted in a significant (P < 0.005) decrease (a maximum of 1.68 ± 0.2 log(10) CFU/mL) in disinfection efficacy when MPDS and either silver or control cases were used. CONCLUSIONS: Silver-copolymerized barrel cases work on conjunction with a hypochlorite producing MPDS in the presence of contact lenses and organic soil to reduce microbial contamination of lens cases. TRANSITIONAL RELEVANCE: Silver-copolymerized barrel contact lens cases show promising in vitro antibacterial activity against bacterial types commonly implicated in contact lens-related corneal infections. This intervention may limit storage case contamination during use and reduce the frequency of contact lens-related microbial disease.