Abstract
Purpose: :
To compare, under in vitro flow conditions, the adherence and biofilm formation of Staphylococcus epidermidis to intraocular lenses (IOLs) made of four different biomaterials (polymethylmethacrylate, silicone, hydrophilic acrylic or hydrophobic acrylic).
Methods: :
IOLs were placed into a bioreactor designed to replicate intraocular conditions. The model consisted in a Tygon tubing connected to a vial. Three septa, placed along the Tygon tubing, allowed respectively the artificial aqueous humor's arrival, its elimination and the bacterial suspension's inoculation. A first pump allowed the aqueous humor movement along the circuit, whereas a second one regulated the flow at which the nutritive environment was regenerated. The whole circuit was placed in a 34° C water bath. At different times (12h, 16h, 24h, 40h, 48h, 60h, 72h), lenses were taken from this environment. Bound bacteria were removed by mechanical scraping of optical faces and measured by counting. The statistical analyses were made using Mann Whitney U and Kruskall Wallis tests. A p value less than 0.05 was considered statistically significant.
Results: :
The model provided the full kinetic of Staphylococcus epidermidis biofilm growth on IOLs made of four different biomaterials. The differences among IOLs were statistically significant from 12h to 48h. From 12h to 48h, adherence was statistically weakest on the hydrophilic acrylic polymer and strongest on the silicone polymer. There was no significant differences between PMMA and the hydrophobic acrylic polymer.
Conclusions: :
Bacterial adhesion and biofilm development to the implant surface must depend on the hydrophobicity or hydrophilicity of the biomaterial. The data suggest that hydrophilic IOLs can help decreasing implant–associated bacterial endophthalmitis as a result of their surface properties.
Keywords: endophthalmitis • intraocular lens • Staphylococcus