Antibiotic Exposure and Reduced Short Chain Fatty Acid Production after Hematopoietic Stem Cell Transplant.

Human studies have shown loss of diversity of the gut microbiome following hematopoietic stem cell transplantation (HSCT) in association with significant gut injury caused by the preparative regimen. Prolonged antibiotic use worsens loss of microbiome diversity and increases risk of complications such as graft-versus-host disease (GVHD). Our data support the hypothesis that loss of intestinal commensals that produce short-chain fatty acids (SCFAs) may increase dysbiosis. Here, we report an extensive longitudinal examination of changes in the luminal SCFAs in children undergoing allogeneic HSCT, and the relationship of those changes to the microbiota and antibiotic exposure. We found significant and progressive alterations in butyrate, and in additional SCFAs in stool in the first 14 days after transplant, a finding not observed in published mouse studies. SCFA levels were lower in children receiving antibiotics with activity against anaerobic organisms. Moreover, day 14 post-HSCT butyrate and propionate levels are lower in children who went on to develop GVHD, although our disease population was small. These data provide insight into the mechanism of prior observations that loss of diversity and increased antibiotic use are associated with GVHD following HSCT. Our findings offer potential modifiable targets to reduce risk of GVHD and improve survival after HSCT.