Detection of Streptococcus and Actinomyces species in initial dental biofilms

Activity: Talk or presentation typesLecture and oral contribution

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Irene Dige - Lecturer

  • Department of Dental Pathology, Operative Dentistry and Endodontics

Combined use of Confocal Laser Scanning Microscopy (CLSM) and Fluorescent in situ Hybridization (FISH) offers new opportunities for analysing the spatial relationships and temporal changes of specific members of microbial populations in intact dental biofilms. The purpose of this study was to analyse the patterns of colonization and population dynamics of Actinomyces spp. relative to Streptococcus spp. and other bacteria during the initial 48 h of biofilm formation. Biofilms were collected on standardized glass slabs mounted in intra-oral appliances and worn by 10 individuals for 6, 12, 24, and 48 h. The biofilms were subsequently labelled with probes against Streptococcus spp. (STR405), Actinomyces spp. (ACT476), or all bacteria (EUB338) and analysed by CLSM. Quantification of bacteria was done by stereological tools: the unbiased counting frame and the 2D fractionator. The studies showed that the combined use of FISH and stereological methods may be useful for obtaining unbiased and reliable information about numerical contributions of specific bacterial populations in young intact biofilms. Observations confirmed previous work that streptococci are the predominant colonizers of early dental biofilm along with Actinomyces spp. There was a notable increase in the total number of bacteria, Streptococcus spp., and Actinomyces spp. over time with a tendency toward a slower growth rate for Actinomyces spp. compared with Streptococcus spp. Actinomyces spp. were mainly located in the inner part of multilayered biofilm. Some Actinomyces spp. microcolonies extended perpendicularly from the supporting surface surrounded by other bacteria forming chimneys. This study has for the first time elucidated some quantitative and qualitative aspects of early stages of oral biofilm formation in situ using species-specific oligonucleotide probes against Actinomyces spp. and further supports a principal role of these species in dental biofilm formation.


Emneord: biofilm
24 Jun 2008

Event (Conference)

TitleA pre-ORCA mini-symposium 2008
CityThesinge, Gronningen


  • biofilm

ID: 11752965