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Strains of Enterococcus faecalis differ in their ability to coexist in biofilms with other root canal bacteria
Author(s) -
Chávez de Paz L. E.,
Davies J. R.,
Bergenholtz G.,
Svensäter G.
Publication year - 2015
Publication title -
international endodontic journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.988
H-Index - 119
eISSN - 1365-2591
pISSN - 0143-2885
DOI - 10.1111/iej.12501
Subject(s) - microbiology and biotechnology , enterococcus faecalis , biofilm , streptococcus gordonii , bacteria , biology , lactobacillus salivarius , proteases , lactobacillus , staphylococcus aureus , biochemistry , genetics , enzyme
Aim To investigate the relationship between protease production and the ability of Enterococcus faecalis strains to coexist in biofilms with other bacteria commonly recovered from infected root canals. Methodology Biofilms with bacteria in mono‐, dual‐ and four‐species communities were developed in flow chambers. The organisms used were Lactobacillus salivarius , Streptococcus gordonii and Actinomyces naeslundii and E. faecalis strains, GUL 1 and OG 1 RF . Biovolume and species distribution were examined using 16S r RNA fluorescence in situ hybridization in combination with confocal microscopy and image analysis. The full proteome of the E. faecalis strains was studied using two‐dimensional gel electrophoresis. Spots of interest were identified using tandem mass spectroscopy and quantified using Delta 2D software. Results All bacteria formed biofilms and an anova analysis revealed that the biofilm biomass increased significantly ( P ≤ 0.01) between 6 and 24 h. L. salivarius , S. gordonii and A. naeslundii formed mutualistic biofilm communities, and this pattern was unchanged when E. faecalis GUL 1 was included in the consortium. However, with OG 1 RF , L. salivarius and S. gordonii were outcompeted in a 24‐h biofilm. Proteomic analysis revealed that OG 1 RF secreted higher levels of proteases, GelE ( P = 0.02) and SprE ( P = 0.002) and a previously unidentified serine protease ( P = 0.05), than GUL 1. Conclusions Different strains of E. faecalis can interact synergistically or antagonistically with a consortium of root canal bacteria. A possible mechanism underlying this, as well as potential differences in virulence, is production of different levels of proteases, which can cause detachment of neighbouring bacteria and tissue damage.