Fecal microbiota transplantation promotes gut microbiome recovery in pediatric hematopoietic stem cell transplant recipients

Introduction Hematopoietic stem cell transplantation (HSCT) profoundly disrupts the gut microbiome and may contribute to adverse post-transplant outcomes. Fecal microbiota transplantation (FMT) has emerged as a strategy to restore microbial diversity; however, data in pediatric HSCT recipients remain limited. Methods We conducted a longitudinal analysis of 17 pediatric HSCT recipients who received FMT. Fecal samples were collected before FMT and at days 7, 14, and 30 after treatment. Gut microbiome composition was analyzed using 16S rRNA gene sequencing. Results Baseline samples showed reduced microbial diversity and a dysbiotic microbial profile. Following FMT, microbial diversity increased progressively, with recovery evident from day 7 and stabilization by day 30. Taxonomic analyses demonstrated depletion of dysbiosis-associated genera and enrichment of beneficial short-chain fatty acid–producing taxa, including Faecalibacterium , Blautia , Subdoligranulum , and Akkermansia . Distinct microbial configurations were observed according to gastrointestinal involvement by acute graft-versus-host disease. Conclusions FMT was associated with progressive restoration of gut microbiome diversity and structure in pediatric HSCT recipients, supporting its potential role as a microbiota-based strategy to promote ecological recovery after HSCT.