Depletion of gut bacteria identified in ankylosing spondylitis

August 1, 2019

New research shows that a newly identified species of gut bacteria is significantly depleted in patients with ankylosing spondylitis.

The majority of microbial diversity in the human gut cannot be found in previously cultured isolates making them unavailable for basic research and the development of biotechnology. Additionally the human gut biome has apparently experienced significant reductions in the number of species, shows a study published in Nature.

It is well know that the gut microbiome has an important role in human health and disease including rheumatic and autoimmune disorders such as spondyloarthritis. Recent advances have used microbial cultures to identify and sequence a large number of gut bacteria with the current study identifying thousands of previously unknown species.

The ultimate goal of this research was to identify and culture a diverse representation of gut bacteria from all over the world in an effort to discover which species were present or absent in healthy and sick humans. Linking differences in gut biome between healthy subjects and those with immune mediated illness may lead to novel diagnostic and therapeutic interventions and improve the quality of human life.

“We hypothesized that human gut MAGs (metagenome-assembled genomes) systematically recovered from public metagenomes could substantially increase the diversity of species with a sequenced genome, and shed light on the biology of uncultivated organisms in the gut microbiome,” wrote study author Stephen Nayfach, Ph.D., of the Department of Energy Joint Genome Institute.

2,283 associations between species and disease were identified. With regards to ankylosing spondylitis, an inflammatory arthritis that affects the spine and large joints, a strong association was found with a newly identified species in the Negativicutes class which was strongly depleted in patients compared to healthy controls and eight orders of magnitude more significant than any previously known species.

“One of the most surprising results from our study was that the majority of microbial diversity in the human gut is not currently represented by cultured isolates, which are important for numerous applications in basic research and biotechnology,” the authors wrote.

While more research is needed to understand how these new species relate to disease pathogenesis these data represent an important first step which will hopefully lead to new treatments and improvements in global health.

REFERENCE

Stephen Nayfach, Zhou Jason Shi, Rekha Seshadri, et al. "New insights from uncultivated genomes of the global human gut microbiome."Nature. 568, pages505–510 (2019) https://doi.org/10.1038/s41586-019-1058-x