Growth of succinate consumer Dialister hominis is supported by Bacteroides thetaiotaomicron

This study revealed an interaction between the gut commensal bacterium Bacteroides thetaiotaomicron JCM 5827T and asaccharolytic bacterium Dialister hominis JCM 33369T, which uses succinate instead of carbohydrates for growth. D. hominis usually forms extremely small colonies on Brucella blood agar plates. However, when co-cultured with B. thetaiotaomicron, D. hominis grew noticeably and formed larger colonies than those in the single culture, especially near B. thetaiotaomicron colonies. Although D. hominis barely grew in Gifu anaerobic medium broth, adding 1% succinate improved its growth. In the mixed culture, the succinate produced by B. thetaiotaomicron was mostly converted to propionate. This result was consistent with the single culture of D. hominis in the succinate-containing broth and our previous report on Phascolarctobacterium faecium, a succinate-utilizing gut bacterium. Our series of studies suggests that syntrophy within the human gut microbiota occurs via succinate. (c) 2022 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).

Automated summary

This study revealed an interaction between the gut commensal bacterium Bacteroides thetaiotaomicron JCM 5827T and asaccharolytic bacterium Dialister hominis JCM 33369T, indicating a syntrophic relationship mediated by succinate metabolism. The co-culture of these two bacteria resulted in enhanced growth of D. hominis, especially near B. thetaiotaomicron colonies. This study suggests that succinate plays a significant role in syntrophy within the human gut microbiota.