Ectopic colonization of oral bacteria in the intestine drives T _H 1 cell induction and inflammation

Abstract

Intestinal colonization by bacteria of oral origin has been correlated with several negative health outcomes, including inflammatory bowel disease. However, a causal role of oral bacteria ectopically colonizing the intestine remains unclear. Using gnotobiotic techniques, we show that strains of Klebsiella spp. isolated from the salivary microbiota are strong inducers of T helper 1 (TH1) cells when they colonize in the gut. These Klebsiella strains are resistant to multiple antibiotics, tend to colonize when the intestinal microbiota is dysbiotic, and elicit a severe gut inflammation in the context of a genetically susceptible host. Our findings suggest that the oral cavity may serve as a reservoir for potential intestinal pathobionts that can exacerbate intestinal disease.

An orally administered oral pathobiont and commensal have comparable and innocuous systemic effects in germ‐free mice

“…In addition, increased levels of bacteria originating from the oral cavity have been reported in the gut microbiota of patients with liver cirrhosis and colorectal cancer, which suggests the existence of an oral‐gut connection. Moreover, it is reported that colonization of oral bacteria in the intestine results in the inflammation by inducing Th1 cells . Thus, oral bacteria can reach the gut and have the potential to induce an immune response.…”

Microbial ecology perturbation in human IgA deficiency

“…It was recently shown that ectopic localization of human salivary microbiota can elicit severe gut inflammation in susceptible host animals (48). It is therefore possible that ectopic oral microbiota could also exert a proinflammatory role in the context of SIgAd.…”

Antibacterial activity of disodium succinoyl glycyrrhetinate, a derivative of glycyrrhetinic acid against Streptococcus mutans

“…Recently, many studies regarding the relationship between oral bacteria and systemic diseases have been published . Oral bacteria can reportedly cause aspiration pneumonia, endocarditis, and artificial joint replacement surgery infections .…”