Amoebicidal efficacy of a novel multi-purpose disinfecting solution: first findings

Free-living amoebae of the genus Acanthamoeba can cause a sight-threatening corneal infection, Acanthamoeba keratitis, mostly in contact lens wearers. The use of ineffective contact lens disinfecting solutions is one of the most important risk factors for this infection. This study concerns a new multi-purpose contact lens disinfecting solution, OPTI-FREE® PureMoist®, tested for its efficacy against Acanthamoeba trophozoites and cysts by using the most probable number technique for amoebic enumeration. Acanthamoeba castellanii ATCC 50373 and an environmental strain of Acanthamoeba genotype T4 isolated from tap water in Istanbul were used during the experiments. OPTI-FREE® PureMoist® achieved total kill (more than a 3-log reduction) of trophozoites of both strains before the manufacturer-recommended disinfection time (6h). In contrast, this solution had limited cysticidal activity against the ATCC strain but more against the environmental strain, with log reductions of 0.75 and 2.20, respectively, after 6h of exposure.