In vitro biofilm distribution on the intraocular lens surface of different biomaterials.

PURPOSE

To study the disposition of bacterial adhesion to intraocular lens (IOL) biomaterials depending on the material and region of the optic IOL surface: center or peripheral edge.

SETTING

School of Medicine, University of Barcelona, Barcelona, Spain.

DESIGN

Experimental study.

METHODS

For the in vivo study, IOLs were explanted from donor ocular globes without clinical symptoms of endophthalmitis. Biofilm formation was qualitatively studied by scanning electron microscopy (SEM). For the in vitro study, 5 IOL biomaterials (hydrophilic acrylic, hydrophobic acrylic, poly[methyl methacrylate] [PMMA], heparinized PMMA, and silicone) were contaminated with a biofilm-producing strain of Staphylococcus epidermidis. Bacterial densities were quantitatively (colony-forming units per area) compared by SEM and direct counting of viable adherent bacteria, according to the biomaterial, region of the IOL optic surface, and time of incubation. For SEM, bacterial adhesion was also qualitatively classified according to the characteristics of biofilm observed: structure, cocci per cluster, homogeneity of cluster distribution, and extracellular matrix production.

RESULTS

At 3 hours of incubation, bacterial counts for hydrophilic acrylic and PMMA IOLs were significantly lower, but at 72 hours there were no statistically significant differences among biomaterials. A higher density of bacteria was observed at the periphery of the IOL's optic of assayed biomaterials for in vitro and in vivo studies. Biofilm formation and the presence of extracellular matrix were predominantly restricted to the edges of IOL optic surface.

CONCLUSION

Bacterial adhesion and biofilm development on the IOL optic surface depended on the region and biomaterial of the IOL.

FINANCIAL DISCLOSURE

Neither author has a financial or proprietary interest in any material or method mentioned.