Microbial Biofilms Interacting with Host Mucosal Surfaces

Biofilms are extremely complex microbial ecosystems forming a "biological film" onto surfaces. In every natural habitat, microbes tend to form biofilm communities, embedded in a biopolymer matrix, attached to the surface, and engaged in collective behaviors. Even in liquid natural environments, microbial biomass is almost exclusively found in a biofilm phenotype rather than freely swimming or floating (planktonic phenotype). In live organisms, mucosal surfaces such as in the mouth, the stomach, the small and large intestine, the endometrium, the vagina, the airways, and on the skin are indeed vastly colonized by microbial biofilms. Mucosal microbes form biofilm communities of microbial aggregates constantly interacting with each other, as much as with host cells. Most current knowledge on how microbes influence host physiology and pathologies rely on findings from free-living (planktonic) mode of life. Hence, understanding how mucosal biofilms influence organ physiology and contribute to pathologic outcomes bear significant interest for the whole scientific community.

Although central in the pathophysiology of many chronic disorders (which can be discussed in this Research Topic), mucosal biofilms can also contribute to homeostatic development of many physiological functions (colonization resistance, immune training, beneficial colonization by probiotics, diet, and xenobiotic metabolism). Studies presented in this Research Topic would aim at surpassing classical views of biofilms being necessarily negative and that mucosal microbes are isolated actors in the context of host/microbial interactions.

This Research Topic also welcomes works aiming to describe microbial microhabitats throughout various mucosal surfaces, this to define the exact localization of each taxon within mucosal biofilms, and to better understand the physiological contribution of microbial biogeography to mucosal health in various organs such as the gut, vagina, airways, and skin both within and between organ systems. The contribution of mucosal biofilms could hold key to understand microbial metabolism of drugs, change in their chemical activity, bioavailability, and could also be discussed in this Research Topic.

We welcome topics on but not limited to the following topics:

• Biologically relevant biofilms models, in vitro to in vivo and ex vivo
• Taxonomic characterization of mucosal biofilms in health and disease
• Characterization of microbial biogeography at mucosal surfaces in health and disease
• Host physiological function alterations by deleterious mucosal biofilm formation
• Role of host environmental changes on biofilm phenotype or composition
• Bidirectional or functional host-biofilms interactions at mucosal surface, in health and diseases conditions
• Intermucosal connections among microbial biofilms (e.g., skin/gut biofilms, bladder/vagina/gut biofilms, gut/oral/skin biofilms, and skin/lung biofilms)
• Role of biofilm lifestyle per se in the protective effect of probiotics