The influence of different alkaline pH conditions on Enterococcus faecalis in planktonic and biofilm mode

PURPOSE: To study the influence of different pH conditions on Enterococcus faecalis(E.faecalis) in planktonic and biofilm mode.METHODS: E.faecalis were prepared in planktonic and biofilm mode and cultured in TSB mediums 2 hours at pH 7,8,9,10,11 and 12.MTT assays were applied to evaluate the survival rate of bacterial cells in different pH value.SAS 6.12 software package was used for statistical analysis.RESULTS: Mild alkaline mediums(pH7-9) had no effect on cell vitality of E.faecalis and high alkaline condition(pH10) led to significant declines of survival rate of cells.The biofilm cells of E.faecalis were more alkaline tolerant than corresponding planktonic cells.CONCLUSION: Biofilm formation is an important step in the development of alkaline tolerance of E.faecalis.