Bacterial interaction in dual-species biofilms

The group of Oral Microbiology of the dentistry faculty of the Free University and the University of Amsterdam is mostly interested in the roles of bacteria and bacteria interaction in dental infectious diseases including periodontitis and dental caries. The pathogens involved and their interactions with commensal bacteria are studied by molecular approaches.

Recently, it was discovered that there are tens of thousands bacterial species present in the oral cavity. These bacteria are organized in a form of biofilm. It was known that strictly anaerobic bacteria Fusobacterium nucleatum and Porphyromonas gingivalis are pathogens for periodontitis, while facultative anaerobic bacteria Streptococcus mutans was a pathogen resulted in dental caries formation. However, not all bacterial species in the biofilm are pathogenic. Commensal bacteria refer to the bacterial species which are beneficial for the oral health. It is our interest to study the interaction between pathogen and commensal bacteria in an in vitro biofilm model. The factors which influence the interaction will be also studied.

Our preliminary study already showed that cario-pathogen S. mutans displayed strain-dependent biofilm formation and antimicrobial resistance. In this project, the influence of commensal bacteria on biofilm formation on various S. mutans strains will be studied mainly by microscopic method. Fluorescent protein labeled bacteria, live/dead staining kit will be used to visualize the interactions in the biofilm.

The goal of this project is
1. Adapt the in vitro biofilm model for bacterial visualization
2. Construct various fluorescent protein labeled bacteria.
3. Visualize the bacterial interaction with microscopic method.


Techniques that will be used in this project are:

  • PCR
  • cloning
  • electro-transformation
  • anaerobic culturing
  • microscopic examination
  • epifluorescent microscope
  • CSLM, etc.


Dongmei Deng
Department of Preventive Dentistry
Academic Centre for Dentistry Amsterdam (ACTA)
Gustav Mahlerlaan 3004, 1081LA Amsterdam
Tel.: 020-5980675