Low diversity gut microbiota dysbiosis: drivers, functional implications and recovery

Abstract

Dysbiosis, an imbalance in microbial communities, is linked with disease when this imbalance disturbs microbiota functions essential for maintaining health or introduces processes that promote disease. Dysbiosis in disease is predicted when microbiota differ compositionally from a healthy control population, but only truly defined when these differences are mechanistically related to adverse phenotypes. For the human gut microbiota, dysbiosis varies across diseases. One common manifestation is replacement of the complex community of anaerobes typical of the healthy adult gut microbiome with a community of lower overall microbial diversity and increased facultative anaerobes. Here we review diseases in which low-diversity dysbiosis has been observed and mechanistically linked with disease, with a particular focus on liver disease, inflammatory bowel disease, and Clostridium difficile infection.

Host-associated microbiomes are predicted by immune system complexity and climate

“…Bio2 explained 59.6% of the variation in external microbiome community structure (Additional file 1: Table S2) have weaker effects on microbiome diversity and structure than do the top-down processes of host physiology and immune function. Just as abiotic factors can influence or reverse top-down effects of predators on ecosystem function [80], the relative strength of host immune function may be similarly disrupted (e.g., antibiotics, immunocompromise) and have strong influences on the host microbiome ( [15,17,31]; Table 1).…”

“…Human microbiomes have been the target of several metaanalyses, revealing insights that indicate microbial involvement in health as well as disease [28], and determining core microbiota associated with body sites [29]. Some meta-analyses have synthesized data in order to investigate disease, physiologic, and developmental states with large effect sizes [30,31]. Meta-analyses of nonhuman host taxa have found a potential link of convergent microbial symbioses between fish and mammals with salinity and trophic level being important drivers of fish gut microbiomes [32].…”

A High-Fat/High-Protein, Atkins-Type Diet Exacerbates Clostridioides ( Clostridium ) difficile Infection in Mice, whereas a High-Carbohydrate Diet Protects

“…The mammalian gut microbiota is crucial for host health and provides colonization resistance against various enteric pathogens (23). Exposure to broad-spectrum antibiotics leads to the depletion of commensal microbiota, an effect which can be exploited by pathogens such as C. difficile (24). Diet is an important force that determines gut 13, 17, 18, 19, 30, and 47.…”

Dietary fat promotes antibiotic-induced Clostridioides difficile mortality in mice

“…Low-diversity dysbiosis is a state of disturbance that is often characterized not only by low alpha-diversity, but also by an increased ratio of facultative to strict anaerobes (21) . Low-diversity dysbiosis is associated with a number of diseases including rCDI (21) .…”

“…Low-diversity dysbiosis is a state of disturbance that is often characterized not only by low alpha-diversity, but also by an increased ratio of facultative to strict anaerobes (21) . Low-diversity dysbiosis is associated with a number of diseases including rCDI (21) . We sought to investigate whether high dietary fat and low dietary fiber influenced if the microbiome developed a compositional state characterized by high levels of facultative anaerobe colonization and lower levels of strict anaerobes.…”