biostudies-literatureUnknownHayase ENHLBI NIH HHSNCI NIH HHSAcute gastrointestinal intestinal GVHD (aGI-GVHD) is a serious complication of allogeneic hematopoietic stem cell transplantation, and the intestinal microbiota is known to impact on its severity. However, an association between treatment response of aGI-GVHD and the intestinal microbiota has not been well-studied. In a cohort of patients with aGI-GVHD (n=37), we found that non-response to standard therapy with corticosteroids was associated with prior treatment with carbapenem antibiotics and loss of <i>Bacteroides ovatus</i> from the microbiome. In a mouse model of carbapenem-aggravated GVHD, introducing <i>Bacteroides ovatus</i> reduced severity of GVHD and improved survival. <i>Bacteroides ovatus</i> reduced degradation of colonic mucus by another intestinal commensal, <i>Bacteroides thetaiotaomicron</i>, via its ability to metabolize dietary polysaccharides into monosaccharides, which then inhibit mucus degradation by <i>Bacteroides thetaiotaomicron</i> and reduce GVHD-related mortality.Research squarers.3.rs-2460097https://www.ebi.ac.uk/biostudies/studies/S-EPMC9915792biostudies-literature<i>Bacteroides ovatus</i> alleviates dysbiotic microbiota-induced intestinal graft-versus-host disease.PMC9915792P30 CA016672R01 HL158796R01 HL124112Hayase EMcDaniel LKPham DLorenzi PLPrasad RPeterson CBRondon GAhmed SSBrown ANOkhuysen PCMukherjee ATsai WBWargo JAMolldrem JJChang CCShpall EJFowler SWTran BQOrtega MRTan LStinson SCSanchez CAGlover IKJenq RRJin YKarmouch JLChapa VAConner MEJamal MAMartens ECHalsey TMShelburne SMehta RSLiu CAlousi AMFlores IIEl-Himri RKHayase TAjami NJChamplin REfalse<i>Bacteroides ovatus</i> alleviates dysbiotic microbiota-induced intestinal graft-versus-host disease.Acute gastrointestinal intestinal GVHD (aGI-GVHD) is a serious complication of allogeneic hematopoietic stem cell transplantation, and the intestinal microbiota is known to impact on its severity. However, an association between treatment response of aGI-GVHD and the intestinal microbiota has not been well-studied. In a cohort of patients with aGI-GVHD (n=37), we found that non-response to standard therapy with corticosteroids was associated with prior treatment with carbapenem antibiotics and loss of <i>Bacteroides ovatus</i> from the microbiome. In a mouse model of carbapenem-aggravated GVHD, introducing <i>Bacteroides ovatus</i> reduced severity of GVHD and improved survival. <i>Bacteroides ovatus</i> reduced degradation of colonic mucus by another intestinal commensal, <i>Bacteroides thetaiotaomicron</i>, via its ability to metabolize dietary polysaccharides into monosaccharides, which then inhibit mucus degradation by <i>Bacteroides thetaiotaomicron</i> and reduce GVHD-related mortality.2023-01-01T00:00:00Z2023 Jan2026-05-30T03:11:52.135Z2026-05-30T03:07:29.286ZS-EPMC99157923677849510.21203/rs.3.rs-2460097/v1