Abstract
Purpose:
We have previously shown that tear proteins extracted from soft contact lenses after one-day of wear possess potent antimicrobial activity, which functions synergistically with certain MPS. This effect is demonstrable during exposure to MPS and can add to the antimicrobial activity of the solution. Here we investigated whether this activity is detectable during conditions that better reflect typical lens disinfection procedures (i.e. incubation at room temperature for four hours in MPS). Additionally, we investigated whether ex vivo protein extracts are still active after one week of wear. In this study we examined whether the MPS used to treat lenses daily during a week of wear affected the activity of the tear proteins.
Methods:
Clinical samples of PureVision lenses worn for a week were collected from four subjects and tear proteins were extracted with ACN/TFA. For each pair of lenses, one was treated with Biotrue each night, and one with Evermoist. Bacterial overnight cultures were prepared and normalized to an OD600 of 1.0 in PBS. Suspensions of Pseudomonas aeruginosa (ATCC 9027) or Staphylococcus aureus (ATCC 6538) were challenged with extracts from worn or unworn lenses in the presence of PBS+EDTA for four hours at room temperature.
Results:
Incubation of S. aureus and P. aeruginosa with tear proteins extracted from worn lenses after treatment with full formulation MPS showed readily observable antibacterial effects after four hours incubation at room temperature. Tear proteins repeatedly exposed to Biotrue (which has been previously shown to stabilize tear proteins) showed greater antimicrobial activity than those exposed to Evermoist.
Conclusions:
These data show that tear proteins absorbed to soft contact lenses possess substantial antimicrobial activity, and that this activity can be modulated by ex vivo treatments of worn lens with fully formulated Biotrue MPS under conditions likely to be encountered during contact lens disinfection. Additionally, the antimicrobial activities of tear proteins extracted from worn lenses remain observable after multiple days of MPS treatments.
Keywords: 486 cornea: tears/tear film/dry eye •
573 keratitis •
659 protein structure/function