Simon Yersin, Jean‐Chrysostome Gody, Florent Mazel, Edgar Djimbele, Synthia Nazita Nigateloum, Bolmbaye Privat Gondje, Sonia Sandrine Vondo, Kandou Kaleb Jephté Estimé, Aline Raub, Youzheng Teo, Serge Ghislain Djorie, Nathalie Kapel, Philippe J. Sansonetti, Pascale Vonaesch, Pascale Vonaesch, for the Afribiota Investigators, Jean‐Marc Collard, Maria Doria, Darragh Duffy, Serge Ghislain Djorie, Tamara Giles-Vernick, Bolmbaye Privat Gondje, Jean‐Chrysostome Gody, Milena Hasan, Nathalie Kapel, Jean-Pierre Lombart, Synthia Nazita Nigatoloum, Laura Parfrey, Maheninasy Rakotondrainipiana, Pierre‐Alain Rubbo, Philippe J. Sansonetti, Ionela Gouandjika-Vasilache, Pascale Vonaesch, Pascale Vonaesch, Sonia Sandrine Vondo
Emerging evidence suggests that ectopic colonization of oral bacteria in the lower digestive tract may exacerbate gastrointestinal disorders. Nevertheless, it remains unclear whether bacteria of oral origin are continuously translocating from the oral cavity to the lower gastrointestinal tract or are locally adapted and persist in their respective niches. We investigated strain translocation dynamics in 44 healthy and stunted children from Bangui, Central African Republic. Using cross-sectional shotgun metagenomic sequencing of saliva, gastric, duodenal, and fecal samples, and isolation and whole-genome sequencing of 87 Streptococcus salivarius isolates, we showed the translocation of members of the genera Streptococcus, Veillonella, Rothia, and Haemophilus. Fecal isolates were more closely related to oral isolates from the same individuals than to those from other individuals. Additionally, saliva showed higher S. salivarius nucleotide diversity compared to other compartments, which is consistent with frequent intraindividual translocations from the oral cavity to the lower gastrointestinal tract. Finally, we showed that overrepresentation of oral bacteria in the duodenum of stunted children is related to increased biomass, while in the colon, it is linked to depletion of overall biomass, including in butyrate-producing strains. Our study quantifies dynamics of oral-to-gut translocation and enrichment of oral taxa, providing key insights into microbiota disruption in stunted children.