Low in vitro Pseudomonas aeruginosa Adhesion to Lehfilcon A Contact Lenses

Abstract

Purpose : Pseudomonas aeruginosa is the most common causative agent implicated in microbial keratitis. During contact lens wear, pathogens may be introduced into the ocular environment, which might cause adverse events. Lehfilcon A is a newly marketed contact lens with a water gradient surface composed of polymeric 2-methacryloyloxyethyl phosphorylcholine (MPC). MPC is reported to impart anti-biofouling properties onto coated substrates. Therefore, in this in vitro experimental study, we evaluated the ability of lehfilcon A to resist adhesion by P. aeruginosa.

Methods : Quantitative bacterial adhesion assays using five strains of P. aeruginosa were conducted to compare the adherence properties of lehfilcon A to five currently marketed contact lenses (comfilcon A, senofilcon C, samfilcon A, senofilcon A, fanfilcon A). Individual contact lenses were incubated in the presence of P. aeruginosa followed by gentle rinsing to remove non-adherent bacteria. Adherent bacteria were recovered from lenses by vigorous vortexing and eluted bacterial colony forming units (CFU) were enumerated by plating. CFUs were normalized to the surface area of each lens. Statistical analyses were performed as t-tests for differences in the mean log CFU/mm² between lens types without assuming equal standard deviation between groups. Bonferroni correction was used to account for multiple comparisons. Adherence of GFP-positive P. aeruginosa to contact lenses was qualitatively evaluated by fluorescent microscopy.

Results : Across five strains of P. aeruginosa, lehfilcon A allowed an average of 1.1 ± 0.1 log CFU/mm² fewer bacteria to bind to the lens compared to the next best performing contact lens material, senofilcon C. Across all strains, this corresponds to an average of 92.0% lower adherence by lehfilcon A compared to all lenses tested, or a difference greater than 2.2x10⁵ live bacteria per lens. Results from fluorescent imaging experiments support the quantitative results, with a clearly greater mass of P. aeruginosa adhering to non-MPC coated lenses.

Conclusions : Lehfilcon A has reduced P. aeruginosa adhesion relative to currently marketed monthly and bi-weekly contact lenses. Contact lenses that limit microbial adhesion coupled with effective contact lens care solutions may be an effective approach to reducing contact lens contamination.

This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.