Abstract
Purpose: :
To compare, under in vitro flow conditions, the adherence and structural organization of Staphylococcus epidermidis biofilm on 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 (2h, 4h, 6h, 8h, 12h), lenses were taken from this environment. Scanning electron microscopy (SEM) was used to count the bound bacteria and to analyze the structural biofilm architecture.
Results: :
The model provided the kinetic of Staphylococcus epidermidis biofilm growth on IOLs made of four different biomaterials. The differences among IOLs were statistically significant from 4h to 6h. Adherence was statistically weakest on the hydrophilic acrylic polymer. From 8h to 12h, the biofilm was too thick to allow an accurate assessment of the bound bacteria. The structural biofilm architecture was modulated by IOLs biomaterials.
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: intraocular lens • endophthalmitis • bacterial disease