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OscillospiraRANK: GenusTAXONOMY: Bacteria -> Terrabacteria group -> Firmicutes -> Clostridia -> Clostridiales -> Ruminococcaceae -> Oscillospira OVERVIEW: Large rods or filaments 3–6 µm in diameter and 10–40 µm in length, divided by closely spaced cross-walls into numerous diskshaped cells. Reproduction by transverse fission. Sometimes motile by means of numerous lateral flagella. Endospores occasionally formed. Growth in pure culture has not been reported. Found only in herbivorous animals. Oscillospira guilliermondii is the only species of this genus. Several recent studies have observed that Oscillospira is associated with leanness or lower body mass index (BMI) in both children and adults, including two recent twin studies 3 and 4. Most notably, one of these studies showed that members of the Oscillospira genus were highly heritable, enriched in lean subjects, and highly positively associated with the leanness-promoting bacterial species Christensenella minuta. Moreover, in germ-free mice that received obese donor microbiota spiked with C. minuta, and consequently gained less weight than their counterparts that were transplanted with nonspiked microbiota, Oscillospira was found to be enriched. A meta-analysis of five microbiota studies in patients with inflammatory bowel diseases (immune dysregulation diseases that affect primarily the intestinal tract, causing pain, diarrhea, and other manifestations) showed Oscillospira to be significantly reduced in patients with Crohn's disease (in both ileal and colonic phenotypes of that disease) . Oscillospira was also reduced in pediatric nonalcoholic steatohepatitis , an inflammatory disease of the liver characterized by deposition of large amounts of fat in the liver. Oscillospira was previously shown to be increased following a dietary intervention that increased fecal bile acids, and the gallstone patients exhibited increased bile acids in their feces. Thus, Oscillospira is probably a genus whose growth is increased under high-bile conditions and may serve as a biomarker for gallstone formation. Interestingly, Oscillospira was strongly correlated with the fraction of secondary bile acids in the feces, in both patients and controls, indicating that it may contribute to the formation of secondary bile acids that are known to protect against infection with Clostridium difficile. Oscillospira probably produces the short-chain fatty acid butyrate. [PMID: 26996766 ] |