Ruminococcus gnavus: friend or foe for human health

Abstract

Ruminococcus gnavus was first identified in 1974 as a strict anaerobe in the gut of healthy individuals, and for several decades, its study has been limited to specific enzymes or bacteriocins. With the advent of metagenomics, R. gnavus has been associated both positively and negatively with an increasing number of intestinal and extra-intestinal diseases from inflammatory bowel diseases to neurological disorders. This prompted renewed interest in understanding the adaptation mechanisms of R. gnavus to the gut, and the molecular mediators affecting its association with health and disease. From ca. 250 publications citing R. gnavus since 1990, 94% were published in the last 10 years. In this review, we describe the biological characterisation of R. gnavus, its occurrence in the infant and adult gut microbiota and the factors influencing its colonisation of the gastrointestinal tract; we also discuss the current state of our knowledge on its role in host health and disease. We highlight gaps in knowledge and discuss the hypothesis that differential health outcomes associated with R. gnavus in the gut are strain and niche specific.

Disease signatures in the gut metagenome of a prospective family cohort of inflammatory bowel disease

“…These taxa have previously been identified to be associated with IBD (Hassouneh et al, 2021; Pisani et al, n.d.). R. gnavus has been extensively reported to be associated with multiple intestinal and extra-intestinal disorders (Crost et al, 2023) and was shown to actively promote inflammation through TLR4 dependent TNF-alpha secretion in response to the polysaccharide glucorhamnan (Henke et al, 2019). F. plautii and C. symbiosum were implicated in bloodstream infections (Elsayed & Zhang, 2004; Karpat et al, 2021), and Bacteroides fragilis is known to be an opportunistic pathogen (Wexler, 2007).…”

Changes in Gut Microbiota After Statin Administration: A New Candidate Mechanism for Statin-Associated New-Onset Type 2 Diabetes

“…[9][10][11] The mechanisms of gut microbiota-mediated modulation of T2D risk, including the role of Ruminococcus gnavus and its association with several features of metabolic syndrome and development of T2D, have been reviewed in detail. 12 R gnavus was robustly associated with an increase in fat mass, waist circumference, serum triglycerides, C-reactive protein, HbA1c (hemoglobin A1c), and a decrease in HDL (highdensity lipoprotein), based on stratified analyses of a large Norwegian cohort using a validated quantitative polymerase chain reaction method. An investigation on long-term associations between gut microbiome composition and incident T2D identified R gnavus as 1 of the 4 species consistently associated with incident T2D.…”

Microbe Profile: Ruminococcus gnavus: the yin and yang of human gut symbionts

“… R. gnavus end-fermentation products of carbohydrates include acetate, formate and ethanol, as well as propanol and propionate but not butyrate [3].…”

“…gnavus to elicit anti- or pro-inflammatory responses is reflected in a mouse model of diseases showing a beneficial or detrimental outcome of R. gnavus supplementation (as reviewed in [3]). At the molecular level, some R.…”

“…In addition of being a member of the ‘normal’ microbiota with beneficial properties, an increasing number of intra- and extra-intestinal diseases have been associated with R. gnavus , as recently compiled [3], illustrating the yin and yang properties of R. gnavus strains.…”