November 21, 2023

Commensal gut bacterium protects from severe intestinal infection

The commensal bacterium Turicibacter sanguinis could be used to protect against severe intestinal infections, Vanderbilt researchers discovered.

Diarrheal diseases are a major contributor to child mortality worldwide, causing about 800,000 deaths per year in children under age 5. 

Multiple different pathogens, including enteropathogenic forms of E. coli, cause diarrhea and gastroenteritis. The study of E. coli in most mouse models requires pretreatment with antibiotics, which kills commensal bacteria in the intestines (gut microbiota) and eliminates whatever role they might play during infection. 

To explore the role of the gut microbiota during intestinal infection, Danyvid Olivares-Villagómez, PhD, and colleagues studied mice infected with Citrobacter rodentium, a pathogen similar to E. coli that does not require antibiotic pretreatment. 

They found that mice missing the commensal bacterium Turicibacter sanguinis had increased susceptibility to severe disease. Colonization of these mice with T. sanguinis reduced susceptibility to severe infection. 

The findings, reported in Infection and Immunity, demonstrate that the presence of T. sanguinis in the intestinal microbiota increases protection from severe C. rodentium infection. 

In studies of young children with diarrhea and acute gastroenteritis reported by others, increased abundance of Turicibacter species in stool samples was associated with healthy controls, supporting a potential association between Turicibacter and decreased susceptibility to diarrheal diseases. The introduction of Turicibacter could be a therapeutic approach to protect from severe intestinal infections, the authors noted. 

Authors of the report include Kristen Hoek, PhD, Kathleen McClanahan, Yvonne Latour, Nicolas Shealy, M. Blanca Piazuelo, MD, Bruce Vallance, PhD, Mariana Byndloss, DVM, PhD, and Keith Wilson, MD. The research was supported by the National Institutes of Health (grants R01DK111671, R01DK128200, T32GM008554, P30DK058404) and the National Science Foundation (grant 1937963).