Metataxonomic Analysis and Fatty Acid Profiling of Feces from Children Undergoing Hematopoietic Stem Cell Transplantation.

Fecal samples at engraftment were characterized by a significant loss of bacterial diversity compared to samples obtained before HSCT and 100 days after HSCT.

• Bacterial composition was analyzed using 16S rRNA gene sequencing
• Three timepoints were compared: before HSCT, at engraftment, and 100 days after HSCT
• Loss of diversity was a consistent finding at the engraftment timepoint across patient groups

Sequences belonging to the genus Blautia were depleted in fecal samples at engraftment.

• Blautia depletion was observed specifically at the engraftment timepoint
• Blautia is a genus associated with gut health and immune modulation
• This depletion was noted relative to pre-HSCT and post-HSCT (day 100) samples

Fecal concentrations of butyrate and acetate were significantly lower at engraftment compared to samples obtained before HSCT and 100 days after HSCT.

• Short-chain fatty acids (SCFAs) were quantified by gas chromatography
• Both butyrate and acetate showed significantly lower concentrations at engraftment
• The reduction in SCFAs was observed across the pediatric patient cohort undergoing HSCT
• SCFA profiles recovered by 100 days post-HSCT

Children who developed GvHD after HSCT had distinct gut microbiota and SCFA profiles compared to children who underwent successful HSCT or died.

• Three outcome groups were compared: successful HSCT, development of GvHD, and death
• Both microbiome composition (16S rRNA sequencing) and SCFA profiles (gas chromatography) differed between groups
• GvHD is described as a major cause of mortality and morbidity after allogeneic HSCT
• The study population consisted of pediatric patients

Allogeneic HSCT and its associated treatments are linked to gut microbiota disruption in pediatric patients, as evidenced by changes across three distinct timepoints.

• Samples were collected at three timepoints: before HSCT, at engraftment, and 100 days after HSCT
• The study included pediatric patients treated for hematologic malignancies
• Gut microbiota changes were assessed using 16S rRNA gene sequencing
• Findings suggest microbiota-targeted strategies could be developed for GvHD prevention during HSCT procedures