TransVivome · Microbial biogeography of the gastrointestinal tract: Towards a better understanding of the drivers of oral and colorectal cancer development.

Microbial biogeography of the gastrointestinal tract: Towards a better understanding of the drivers of oral and colorectal cancer development.

The human microbiome plays essential roles in modulating human health and disease. Based on preliminary data as well as previously published work, I had hypothesised that 1) the oral cavity acts as a reservoir of microbes which continuously seed the gut and that 2) specific aberrations of the microbiota along the gastrointestinal tract (GIT) are linked to the development of colorectal cancer (CRC). My aim was to test these hypotheses through the integration of metagenomic and metatranscriptomic data generated from microbial consortia in the colons/recta as well as oral cavities of patients with CRC, and compare these to healthy individuals. In an attempt to address the questions: which microbial strains survive passage from the oral cavity in to the gut? And does the mouth act as a reservoir for strains driving CRC development? Using a cohort of 26 CRC and 16 control, coupled saliva and stool samples, shotgun metagenomic sequences were generated. We found that the transmissibility of oral microbes to the gut via swallowing of saliva is not the same for all species. In many cases, subspecies are restricted to one of the two body sites. Due to the small size of the cohort, results are currently inconclusive with regards to disease specific strain complements in either the oral cavity or lower gastrointestinal tract. Using a much larger cohort (300 individuals) of publicly available saliva-stool coupled sequences from Fiji, China, France and Germany we were able to comment on oral to gut transmission. We showed that few species overlap between the oral and gut communities and that of these species approximately half comprised a sub-species specialised to the separate environments. This was further expanded on with other oral micro-environments, such as plaque, tongue and bucca-mucosa. Using novel methods for low resolution SNP detection and gene clustering we were able to reconstruct the peripheral genome of many of these species and determine potential localised adaptations which restrict subspecies to specific microenvironments along the gastrointestinal tract.

Текст от CORDIS, на английски · Данни: CORDIS, © Европейски съюз