Extensive transmission of microbes along the gastrointestinal tract

Abstract

The gastrointestinal tract is abundantly colonized by microbes, yet the translocation of oral species to the intestine is considered a rare aberrant event, and a hallmark of disease. By studying salivary and fecal microbial strain populations of 310 species in 470 individuals from five countries, we found that transmission to, and subsequent colonization of, the large intestine by oral microbes is common and extensive among healthy individuals. We found evidence for a vast majority of oral species to be transferable, with increased levels of transmission in colorectal cancer and rheumatoid arthritis patients and, more generally, for species described as opportunistic pathogens. This establishes the oral cavity as an endogenous reservoir for gut microbial strains, and oral-fecal transmission as an important process that shapes the gastrointestinal microbiome in health and disease.

Tracing the accumulation of in vivo human oral microbiota elucidates microbial community dynamics at the gateway to the GI tract

“…Not coincidentally, the presence of Fusobacterium nucleatum in paired saliva and colon samples of the patients with colorectal cancer has been reported, 2 3 raising interest in whether disease starts in the mouth or in the intestine. [4][5][6] Another reason people are interested in oral microbes is their potentials serving as biomarkers for systemic diseases. 3 7-9 In this study, we examined how long the collapsed bacterial community can recover to its initial state when suffering from disturbance and whether oral microbes have sufficient robustness to serve as biomarkers.…”

Non-surgical Periodontal Treatment Restored the Gut Microbiota and Intestinal Barrier in Apolipoprotein E−/− Mice With Periodontitis

“…Subgingival biofilms in individuals with periodontal diseases present continually reservoirs of gramnegative bacteria (Li et al, 2000). It is reported that species associated with periodontitis showed evidence for mouth-togut transmission (Schmidt et al, 2019). Swallowing high doses of periodontal pathogenic microorganisms for a long time might induce dysbiosis of the intestinal microbiota.…”

Gut microbiome in serious mental illnesses: A systematic review and critical evaluation

“…a ↑↓ arrows indicate increase or decrease in relative abundance, when referring to taxonomic differences. factor that can determine gut composition (Schmidt et al, 2019). The increased presence of lactic acid bacteria in this population and its association with worse clinical, inflammatory, and metabolic profiles is surprising given that lactic acid bacteria are often considered healthpromoting and anti-inflammatory (Ménard et al, 2004).…”