Susceptibility of Acanthamoeba to multipurpose lens-cleaning solutions

Abstract

The present study investigated the susceptibility of Acanthamoeba spp. trophozoites to two multipurpose systems for cleaning and maintenance of contact lenses. Three strains of trophozoites from the ATCC (A. castellani T4, A. castellani Neff, and A. polyphaga) and two Acanthamoeba isolates obtained from swimming pools (PT5 and PO1) were placed in monoxenic culture. To test their survival in cleaning solutions for contact lenses, the trophozoites were exposed for 4 and 24 h to two multipurpose solutions (A and B), and were then inoculated into a new monoxenic culture. Amoebic growth on the plates was observed after 72 h of incubation. Trophozoites from all three ATCC strains and one isolate from a swimming pool (PO1) grew in all plates after 4 h of exposure to solutions A and B. After 24 h, the ATCC strains and the PO1 isolate showed growth in most of the plates treated. Only the PT5 isolate showed susceptibility to both solutions over the time intervals tested. The two solutions were not completely effective against most strains and isolates over the time intervals tested. These results are important, since species of Acanthamoeba are widely distributed in the environment and are potential agents of eye pathologies.

In Vitro Evaluation of the Combination of Melaleuca alternifolia (Tea Tree) Oil and Dimethyl Sulfoxide (DMSO) against Trophozoites and Cysts of Acanthamoeba Strains. Oxygen Consumption Rate (OCR) Assay as a Method for Drug Screening

“…Unfortunately, many commercial solutions for lens hygiene containing PHMB were ineffective against Acanthamoeba contamination in contact lenses, as demonstrated by a study conducted in Korea [11]. Similar findings have been observed for many multipurpose cleansing solutions in other studies [12][13][14][15][16].…”

BCLA CLEAR - Contact lens wettability, cleaning, disinfection and interactions with tears

“…While there is interest in incorporating the testing of care solutions against Acanthamoeba for regulatory purposes, there are important issues that need to be solved, such as standardisation of the testing procedure [276,[280][281][282]. Although some care solutions might be effective against Acanthamoeba trophozoites, many are not against the dormant highly resistant cyst stage [277,278,[283][284][285][286][287][288]. The long-term survival and resistance of cysts to disinfectants adds complexity with regards to developing safe and effective contact care disinfecting solutions against Acanthamoeba [289].…”

A history of over 40 years of potentially pathogenic free-living amoeba studies in Brazil - a systematic review

“…(67)(68)(69)(70)(71)(72)(73) Two studies have explored alternatives such as photodynamic therapy by using riboflavin and curcuminoids as photosensitisers for treating Acanthamoeba keratitis. (74,75) The effectiveness of contact lens multipurpose solutions against Acanthamoeba, a topic debated by the FLA community, (76) has been also investigated in Brazil, (77,78) including the suggestion of imidazolium salt, an antiamoebic substance, as a suitable option for lens storage. (79) Alternatively, therapeutic strategies were concerned with molecules essential to cell division, energy production, cell differentiation, or movement.…”