Effect of a multipurpose contact lens solution on the survival and binding of Acanthamoeba species on contact lenses examined with a no-rub regimen.

Purpose: To determine the effect of a multipurpose contact lens solution (ReNu MultiPlus Multi-Purpose Solution [RMP]) on the relative survival and binding of trophozoites and cysts of Acanthamoeba on hydrogel lenses with a no-rub regimen.

Methods: A stand-alone test procedure with RMP was conducted with and without the presence of organic soil (1 x 10(7) colony-forming units/mL heat-killed cells of Saccharomyces cerevisiae in heat-inactivated fetal bovine serum). Survival of amoebae on hydrogel contact lenses exposed to RMP was determined with a no-rub care regimen.

Results: ReNu MultiPlus Multi-Purpose Solution reduced the number of recoverable amoebae by more than 95% within 4 hours of inocula of 10(5) trophozoites and cysts, regardless of the presence or absence of an organic soil. Amoebae, particularly cysts, were readily rinsed from contact lenses, including silicone hydrogels, without rubbing after exposure to RMP.

Conclusions: The efficacy of RMP for Acanthamoeba was not appreciably altered in the presence of organic soil in a no-rub protocol. The antimicrobial activity, in part, appeared to be a combination of reducing the capacity for binding of representative Acanthamoeba to the lens by alteration of morphology, often followed by lysis of the amoebae.