In vitroevaluation of the effect of different disinfectants on the biofilm ofStaphylococcus epidermidisandStaphylococcus aureusformed on acrylic ocular prostheses

The aim of this study was to evaluate the effect of disinfectants on the biofilm ofStaphylococcus aureusandStaphylococcus epidermidisformed on the acrylic surface of ocular prostheses. In this study, 396 acrylic specimens were manufactured (50% forStaphylococcus epidermidis, and 50% forStaphylococcus aureus). For each bacterium, 66 specimens were subjected to biofilm formation on their surfaces for 24 hours, 66 specimens were subjected to biofilm formation on their surfaces for 48 hours, and 66 specimens were subjected to biofilm formation on their surfaces for 72 hours. Then, they were divided into groups according to disinfection method (n = 6): sterile distilled water for 10, 15, 30 min, and 6 hours (control); soap for 30 min (NES30); Opti-Free for 30 min (OPF30) and 6 h (OPF6); Efferdent for 15 min (EFF15); and 0.5%, 2%, and 4% chlorhexidine for 10 min (0.5% CHX10, 2% CHX10, and 4% CHX10). After the treatments, the specimens were vortexed to release the biofilm and the counting of bacterial colonies was performed (CFU/mL). Three-way ANOVA and the Tukey-Kramer HSD test were used (alpha = 0.05). ForStaphylococcus epidermidis, there was no significant difference between NES30, OPF30, and OPF6 with their respective control groups; nor between NES30, OPF30, and OPF6 themselves, regardless of the biofilm development period (P>0.05). ForStaphylococcus aureus, there was no significant difference between NES30 and OPF30 with their control group; nor between NES30 and OPF30 themselves, regardless of the biofilm development period (P>0.05). ForStaphylococcus aureus, OPF6 showed a significant reduction in the number of CFU/mL when compared with its control group, NES30, and OPF30, regardless of the biofilm development period (P<0.05). For both bacteria, 0.5% CHX10, 2% CHX10,4% CHX10, and EFF15 showed a significant reduction in the number of CFU/mL when compared with their control groups, NES30, OPF30, and OPF6, regardless of the biofilm development period (P<0.05). Therefore, EFF15 and CHX (0.5%, 2% and 4%) were effective in reducingStaphylococcus epidermidisandStaphylococcus aureuson acrylic surfaces. NES30 and OPF (30 and 6) are not recommended.