A new study published in Nature reveals that variations in gut microbiome composition may significantly influence susceptibility to severe sepsis outcomes. Researchers from the Korea Research Institute of Bioscience and Biotechnology’s Infectious Disease Research Center used genetically similar female mice with different gut microbiomes to investigate why sepsis outcomes vary dramatically, infecting them with Acinetobacter baumannii, a highly resilient bacterium that can lead to sepsis.
The vulnerable mice had a higher concentration of Muribaculaceae bacteria in their gut, comprising about 28% of the microbiome in poor surviving mice compared to only 0.15% in better surviving mice. Mice with worse survival showed an early and strong inflammatory response, which later led to more bacteria in the blood, lungs and spleen. Importantly, one strain of bacteria—Sangeribacter muris KT1-3—appeared most prominent in the microbiome of mice with worse survival. When normally high-surviving mice were housed with KT1-3 mice, their survival fell dramatically to 10%, suggesting this bacterial strain worsens inflammation during certain infections and increases sepsis severity.
According to Dr. Andrew Fleming, section chief of Infectious Diseases & Immunology at NYU Langone Hospital, Brooklyn, it has been “known for years” that gut bacteria can be released into the bloodstream during sepsis, worsening the inflammatory response. However, the study adds evidence that a diverse and healthy gut microbiome is protective against severe sepsis, while “a dysregulated microbiome—for example, one severely altered by antibiotics—can impair or worsen the immune system’s response during sepsis.”
A key limitation: Sangeribacter muris is not typically found in humans, so the exact mechanism cannot be directly extrapolated to people. Well-designed clinical trials are needed to explore how similar gut microbiome effects may influence sepsis outcomes in humans.
This article is an AI-assisted summary. All facts and figures are drawn from the original report: https://newspub.live/health/study-reveals-hidden-gut-factor-that-may-make-some-people-more-susceptible-to-sepsis/