Development of In vitro Multi-Species Biofilms to Explore Strategies to Prevent Biofilm-Associated Oral Diseases

[摘要] More than 80% of infectious diseases are caused by microbial biofilms. In the oral cavity, biofilms are composed of hundreds of distinct bacteria. The accumulation of oral biofilms can lead to caries and periodontal disease. From a public health standpoint, the cost of treatment for oral diseases remain high, at over $100 billion dollars per year in US alone. The primary aim of this project was to evaluate new anti-biofilm agents using novel in vitro biofilm model systems. In addition, the biology of oral biofilms and their relationship to oral diseases are discussed in the context of their development in laboratory biofilm model systems.Nisin is a unique bacteriocin generated by a group of Lactococcus and Streptococcus species. The objective of the first part of the work was to determine if nisin exhibited broad-spectrum antimicrobial effects against oral bacteria. In addition, the presented work showed that nisin inhibited the growth and maintenance of saliva derived biofilms developed in static and controlled-flow biofilm model systems. Even at higher concentrations, nisin did not exhibit cytotoxic effects on human oral cells. L-arginine is an amino acid that is present in low levels in the oral cavity. At lower concentrations, L-arginine is a nutrient source for arginolytic bacteria. The objective of the second part of the work was to explore the short-term effects of high concentrations of L-arginine on oral biofilms. A modified Swinnex model system was used to develop the multi-species oral biofilms and the FlowCam® was used to monitor the biofilm dispersion. In a dose-dependent manner, L-arginine treatment resulted in biofilm destabilization through enhanced biofilm dispersion. Based on community analyses of the biofilms and the dispersed cells, L-arginine did not result a significant shift in the community compared to the water-treated controls.In summary, the work presented in this thesis demonstrated that complex biofilms, that contain species present in the human oral cavity, can be developed using three different in vitro biofilm model systems. In addition, we showed that nisin and L-arginine has high potential to disrupt the in vitro developed multi-species biofilms and these compounds have potential as novel anti-biofilm agents.

[发布机构] University of Michigan

[效力级别] Microbiology and Immunology

[关键词] Development of In vitro Multi-Species Biofilms to Explore Strategies to Prevent Biofilm-Associated Oral Diseases;Microbiology and Immunology;Science;Oral Health Sciences