An in vitrobiofilm model system maintaining a highly reproducible species and metabolic diversity approaching that of the human oral microbiome

Anna Edlund, Youngik Yang, Adam P Hall, Lihong Guo, Renate Lux, Xuesong He, Karen E Nelson, Kenneth H Nealson, Shibu Yooseph, Wenyuan Shi, Jeffrey S McLean

Our knowledge of microbial diversity in the human oral cavity has vastly expanded during the last two decades of research. However, much of what is known about the behavior of oral species to date derives from pure culture approaches and the studies combining several cultivated species, which likely does not fully reflect their function in complex microbial communities. It has been shown in studies with a limited number of cultivated species that early oral biofilm development occurs in a successional manner and that continuous low pH can lead to an enrichment of aciduric species. Observations that in vitro grown plaque biofilm microcosms can maintain similar pH profiles in response to carbohydrate addition as plaque in vivo suggests a complex microbial community can be established in the laboratory. In light of this, our primary goal was to develop a robust in vitro biofilm-model system from a pooled saliva inoculum in order to study the stability, reproducibility, and development of the oral microbiome, and its dynamic response to environmental changes from the community to the molecular level.