Vitamin B12 produced by Cetobacterium somerae improves host resistance against pathogen infection through strengthening the interactions within gut microbiota

Abstract

Background Pathogen infections seriously affect host health, and the use of antibiotics increases the risk of the emergence of drug-resistant bacteria and also increases environmental and health safety risks. Probiotics have received much attention for their excellent ability to prevent pathogen infections. Particularly, explaining mechanism of action of probiotics against pathogen infections is important for more efficient and rational use of probiotics and the maintenance of host health. Results Here, we describe the impacts of probiotic on host resistance to pathogen infections. Our findings revealed that (I) the protective effect of oral supplementation with B. velezensis against Aeromonas hydrophila infection was dependent on gut microbiota, specially the anaerobic indigenous gut microbe Cetobacterium; (II) Cetobacterium was a sensor of health, especially for fish infected with pathogenic bacteria; (III) the genome resolved the ability of Cetobacterium somerae CS2105-BJ to synthesize vitamin B12 de novo, while in vivo and in vitro metabolism assays also showed the ability of Cetobacterium somerae CS2105-BJ to produce vitamin B12; (IV) the addition of vitamin B12 significantly altered the gut redox status and the gut microbiome structure and function, and then improved the stability of the gut microbial ecological network, and enhanced the gut barrier tight junctions to prevent the pathogen infection. Conclusion Collectively, this study found that the effect of probiotics in enhancing host resistance to pathogen infections depended on function of B12 produced by an anaerobic indigenous gut microbe, Cetobacterium. Furthermore, as a gut microbial regulator, B12 exhibited the ability to strengthen the interactions within gut microbiota and gut barrier tight junctions, thereby improving host resistance against pathogen infection.

Host evolution shapes gut microbiome composition in Astyanax mexicanus

“…Cetobacterium is common in the microbiome of herbivorous fish and is thought to assist in carbohydrate metabolism (Tsuchiya et al., 2007 ). One predominant species, Cetobacterium somerae , has been shown to produce vitamin B12 which provides resistance to pathogen infection (Qi et al., 2023 ). C. somerae has also been shown to improve glucose homeostasis when administered to zebrafish, Danio rerio , through the production of acetate and modulation of the gut‐brain axis (Wang et al., 2021 ).…”

“…to produce vitamin B12 which provides resistance to pathogen infection (Qi et al, 2023). C. somerae has also been shown to improve glucose homeostasis when administered to zebrafish, Danio rerio, through the production of acetate and modulation of the gut-brain axis (Wang et al, 2021).…”

Early-Life Fecal Transplantation from High Muscle Yield Rainbow Trout to Low Muscle Yield Recipients Accelerates Somatic Growth through Respiratory and Mitochondrial Efficiency Modulation

“…Oxygen-saturated environments have been shown to promote pathogenic bacterial virulence [ 37 ]. Non-fluctuation intestinal redox status impacts gut microbiome compositional stability and functional profile resiliency [ 38 ]. Additionally, B 12 has been shown to safeguard against pathogenic infection, specifically promoting gut barrier tight junction activity in zebrafish by increasing the expression of canonic tight junction proteins (Claudin15, Occludin, and Zo-1) [ 38 ].…”

“…Non-fluctuation intestinal redox status impacts gut microbiome compositional stability and functional profile resiliency [ 38 ]. Additionally, B 12 has been shown to safeguard against pathogenic infection, specifically promoting gut barrier tight junction activity in zebrafish by increasing the expression of canonic tight junction proteins (Claudin15, Occludin, and Zo-1) [ 38 ]. Pronounced mortality in the high-yield recolonized group observed after antibiotic treatment and microbiome cocktail administration may be explained, in part, by the absence of C. somerae and the negative implications of aerobically saturated intestinal environments.…”

Systemic metabolic depletion of gut microbiome undermines responsiveness to melanoma immunotherapy

“…Another potential probiotic candidate for improving immunotherapy outcomes could be Propionibacterium freudenreichii because of its ability to produce cobalamin. Cobalamin-producing bacteria strengthen interactions within the gut microbiota and intestinal barrier tight junctions ( Qi et al, 2023 ), which is beneficial for host resistance to pathogen infection and potentially beneficial for immunotherapy outcomes. However, the most promising prospects lie in the potential development of F. prausnitzii –based probiotics for clinical use ( Khan et al, 2023 ).…”