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A single gene of a commensal microbe affects host susceptibility to enteric infection

Mi Young Yoon1, Kyung Bae Min1, Kang-Mu Lee1

  • 1Department of Microbiology and Immunology, Brain Korea 21 Project for Medical Sciences, Yonsei University College of Medicine, Seoul 03722, Korea.

Nature Communications
|May 14, 2016
PubMed

Insights

A specific gut bacterium, atypical Escherichia coli (atEc), promotes Vibrio cholerae infections by reducing reactive oxygen species (ROS). This discovery highlights how single commensal microbes can influence host susceptibility to pathogens.

Area of Science:

  • Microbiology
  • Immunology
  • Gastroenterology

Background:

  • The gut microbiome plays a crucial role in host health and defense against pathogens.
  • Mechanisms of interaction between commensal gut bacteria and intestinal pathogens are not fully understood.

Purpose of the Study:

  • To investigate how commensal gut microbes influence susceptibility to intestinal pathogens.
  • To identify specific bacterial factors that mediate pathogen-host interactions.

Main Methods:

  • Identification and characterization of an atypical Escherichia coli (atEc) strain.
  • Mouse models of Vibrio cholerae infection, including neonatal and antibiotic-treated adult mice.
  • Assessment of reactive oxygen species (ROS) levels in the mouse intestine.
  • Genetic manipulation of the atEc strain to assess the role of ROS resistance.

Main Results:

  • An atypical E. coli (atEc) strain, unable to ferment lactose, was found to expand in antibiotic-treated mice.
  • Neonatal mice colonized with atEc showed increased susceptibility to V. cholerae infection compared to those colonized with typical E. coli.
  • atEc colonization led to decreased intestinal ROS levels, favoring V. cholerae proliferation.
  • An atEc mutant lacking ROS degradation capability failed to enhance V. cholerae infection.

Conclusions:

  • A single commensal bacterial species, through specific gene products, can significantly impact host susceptibility to infection.
  • Resistance to reactive oxygen species (ROS) by commensal bacteria like atEc can create a favorable environment for pathogens such as V. cholerae.
  • This study reveals a novel mechanism by which gut microbiota composition influences infectious disease outcomes.

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