Strains of Enterococcus faecalis differ in their ability to coexist in biofilms with other root canal bacteria. (31st July 2015)

• Record Type: Journal Article
• Authors: Chávez de Paz, L. E.; Davies, J. R.; Bergenholtz, G.; Svensäter, G.
• Is Part Of: International endontic journal. Volume 48:Number 10(2015:Oct.)
• Page Start: 916
• Page End: 925
• Publication Date: 2015-07-31
• Subjects: Endodontics -- Periodicals; 617.6342
• DOI: 10.1111/iej.12501
• Languages: English
• ISSNs: 0143-2885

Abstract

<abstract abstract-type="main" id="iej12501-abs-0001"> <title>Abstract</title> <sec id="iej12501-sec-0001" sec-type="section"> <title>Aim</title> <p>To investigate the relationship between protease production and the ability of <italic>Enterococcus faecalis</italic> strains to coexist in biofilms with other bacteria commonly recovered from infected root canals.</p> </sec> <sec id="iej12501-sec-0002" sec-type="section"> <title>Methodology</title> <p>Biofilms with bacteria in mono‐, dual‐ and four‐species communities were developed in flow chambers. The organisms used were <italic>Lactobacillus salivarius</italic>, <italic> Streptococcus gordonii</italic> and <italic>Actinomyces naeslundii</italic> and <italic>E. faecalis</italic> strains, GUL1 and OG1RF. Biovolume and species distribution were examined using 16S <italic>r</italic>RNA fluorescence <italic>in situ</italic> hybridization in combination with confocal microscopy and image analysis. The full proteome of the <italic>E. faecalis</italic> strains was studied using two‐dimensional gel electrophoresis. Spots of interest were identified using tandem mass spectroscopy and quantified using Delta 2D software.</p> </sec> <sec id="iej12501-sec-0003" sec-type="section"> <title>Results</title> <p>All bacteria formed biofilms and an <sc>anova</sc> analysis revealed that the biofilm biomass increased significantly (<italic>P</italic> ≤ 0.01) between 6 and 24 h. <italic>L. salivarius</italic>, <italic> S. gordonii</italic> and <italic>A. naeslundii</italic> formed mutualistic biofilm communities, and this pattern was unchanged when <italic>E. faecalis </italic>GUL1 was included in the consortium. However, with OG1RF, <italic> L. salivarius</italic> and <italic>S. gordonii</italic> were outcompeted in a 24‐h biofilm. Proteomic analysis revealed that OG1RF secreted higher levels of proteases, GelE (<italic>P</italic> = 0.02) and SprE (<italic>P</italic> = 0.002) and a previously unidentified serine protease (<italic>P</italic> = 0.05), than GUL1.</p> </sec> <sec id="iej12501-sec-0004" sec-type="section"> <title>Conclusions</title> <p>Different strains of <italic>E. faecalis</italic> 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.</p> </sec> </abstract>