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Updated: May 21, 2026

Bile Salt-induced Biofilm Formation in Enteric Pathogens: Techniques for Identification and Quantification
Published on: May 6, 2018
Extracellular dextran and DNA affect the formation of Enterococcus faecalis biofilms and their susceptibility to 2%
Weilan Li1, Hongyan Liu, Qiong Xu
1Changsha Stomatological Hospital, Changsha, China.
Introduction:
Enterococcus faecalis is frequently recovered from root-filled teeth with refractory apical periodontitis. The ability of E. faecalis to form a matrix-encased biofilm contributes to its pathogenicity; however, the role of extracellular dextran and DNA in biofilm formation and its effect on the susceptibility of the biofilm to chlorhexidine remains poorly understood.
Methods:
E. faecalis biofilms were incubated on dentin blocks. The effect of a dextran-degrading enzyme (dextranase) and DNase I on the adhesion of E. faecalis to dentin was measured using the colony-forming unit (CFU) counting method. CFU assays and confocal laser scanning microscopy were used to investigate the influence of dextranase and DNase I on the antimicrobial activity of 2% chlorhexidine.
Results:
The CFU count assays indicated that the formation of biofilms by E. faecalis was reduced in cells treated with dextranase or DNase I compared with that in untreated cells (P < .05). In addition, we found that treating E. faecalis biofilms with dextranase or DNase I effectively sensitized the biofilms to 2% chlorhexidine (P < .05).
Conclusions:
Both dextranase and DNase I decrease the adhesion of E. faecalis to dentin and sensitized E. faecalis biofilms to 2% chlorhexidine.
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