[Phenotypic characterization of Staphylococcus epidermidis isolated from patients with endophthalmitis].

Objective: To carry out the phenotypic characterization of Staphylococcus epidermidis isolated from endophthalmitis developed after cataract extraction and implantation of an intraocular lens. This bacteria produces a biofilm, adheres to polystyrene and host proteins such as collagen and fibronectine, significant virulence factors.

Methods: Five S. epidermidis strains were isolated from cases of endophthalmitis, they developed after crystalline extraction and implantation of an intraocular lens. We assessed if these strains adhere to polystyrene, to Type I collagen and to fibronectine and if bacteria produced biofilm. Finally, the bacterial surface proteins were obtained and analyzed using polyacrylamide gel electrophoresis.

Results: All five bacterial strains adhered to polystyrene, with a maximum adherence time of 105 min; they also displayed adherence to fibronectine but only two to collagen. Only two strains were weak biofilm producers. We identified proteins that by molecular weight are similar to those identified in the literature as proteins binding to biomaterials.

Conclusions: As the strains that we studied were not biofilm-forming they should be considered as non-pathogenic. Nevertheless, they meet the initial criteria of pathogenicity and adherence, aside from being isolated from an intraocular infectious process and being able to provoke endophtalmitis when inoculated in rabbit eyes.