Blautia, a recently discovered bacterial genus, groups several abundant gastrointestinal (GI) bacteria previously assigned to the Ruminococcus genus – particularly those related to Ruminococcus obeum. Blautia is capable of using hydrogen and carbon dioxide to create acetate. Species within this genus are among the most abundant members of the GI tract, ranging from 2.5% to 16% of the total human microbiota.

Researchers have found levels of species within this genus are often diminished in elderly patients. In addition, diminished levels have also been found in mucosal samples of colorectal cancer patients, although more research is needed. Alternatively, increased levels of Blautia species have been observed in irritable bowel syndrome (IBS) patients, but this may reflect higher gas levels, which are produced by Dorea, a genus of bacteria that can be utilized by Blautia.

Other interesting research done by the Memorial Sloan Kettering Cancer Center may indicate that small amounts of Blautia within a patients’ microbiome may reduce the risk of graft-versus-host-disease (GVHD) after a bone marrow transplant (BMT). Researchers found that despite Blautia’s presence prior to transplantation, patients often lose this common microbe due to the treatment or not eating, which is common in BMT patients. If a patient still carried Blautia in their gut microbiome after the transplant, they were significantly less at risk for GVHD, a life-threatening condition.


Chen, W., Liu, F., Ling, Z. et al. “Human Intestinal Lumen and Mucosa-Associated Microbiota in Patients with Colorectal Cancer.” PloS ONE. 7(6): e39743; doi: 10.1371/journal.pone.0039743

Grisham, J. “Bacteria May Hold the Key to Preventing Dangerous Side Effect of Transplants.” Memorial Sloan Kettering Cancer Center. (2014). Memorial Sloan Kettering Cancer Center

Jenq, R.R., Taur, T., Devlin, S.M. et al. “Intestinal Blautia is Associated with Reduced Death from Graft-versus-Host Disease.” Biology of Blood and Marrow Transplantation. (2015). 21(8) 1373-83; doi:,/p>

Murat Eren, A., Sogin, M.L., Morrison, H.G. et al. “A single genus in the gut microbiome reflects host preference and specificity.” The ISME Journal. (2015). 9: 90-100; doi: 10.1038/ismej.2014.97

Rajilić-Stojanović, M., de Vos W.M. “The first 1000 cultured species of the human gastrointestinal microbiota.” FEMS Microbiology Reviews. (2014). 38(5) 996-1047; doi: 10.1111/1574-6976.12075