Fig. 1.

Optical density measurement at 600 nm per cm² for both samples planktonic and biofilm of S. epidermidis CIP 444 growing on borosilicate (A, B) and polystyrene (C, D) surfaces. The area of the studied surfaces was calculated for comparison. The biofilm and planktonic were separated on a daily basis and optical density was measured for each, for a period of seven days using a UV–Vis spectrophotometer then converted as OD per cm². The letters (a, b, c) represent significant differences in the biofilm density during the seven days on the two surfaces after applying ANOVA followed by Duncan's multiple range test (at p level <0.05). Error bars indicate standard deviations of the means.