Preliminary studies on the amoebicidal efficacy of contact lens disinfection systems

This preliminary study evaluated the efficacy of contact lens disinfection systems against Acanthamoeba castellanii, tested with and without co-incubation with Pseudomonas aeruginosa.

First, disinfection systems containing 3% hydrogen peroxide, 0.00005% polyaminopropyl biguanide or 0.001% polyquaternium were challenged with A. castellanii for 72 h. Surviving cells were enumerated. Second, A. castellanii were co-incubated with P. aeruginosa for 48 h, then exposed to the disinfectants for 6 h.

There was zero survival of A. castellanii in hydrogen peroxide and variable survival in multipurpose systems. Following co-incubation, A. castellanii survival increased significantly (P = 0.015).

Multipurpose systems have variable anti-amoeba activity and storage cases contaminated by bacteria may enhance amoeba survival.