Project description:<p><strong>BACKGROUND:</strong> Hematopoietic stem cell transplantation is a curative procedure for a variety of conditions. Despite major advances, a plethora of adverse clinical outcomes can develop post-transplantation including graft-versus-host disease and infections, which remain the major causes of morbidity and mortality. There is increasing evidence that the gastrointestinal microbiota is associated with clinical outcomes post-hematopoietic stem cell transplantation. Herein, we investigated the longitudinal dynamics of the gut microbiota and metabolome and potential associations to clinical outcomes in pediatric hematopoietic stem cell transplantation at a single centre.</p><p><strong>RESULTS:</strong> On admission (baseline), the majority of patients presented with a different gut microbial composition in comparison to healthy control children with a significantly lower alpha diversity. A further, marked decrease in alpha diversity was observed immediately post-transplantation and in most microbial diversity, and composition did not return to baseline status while hospitalized. Longitudinal trajectories identified continuous fluctuations in microbial composition, with the dominance of a single taxon in a significant proportion of patients. Using pam clustering, three clusters were observed in the dataset. Cluster 1 was common pre-transplantation, characterized by a higher abundance of <em>Clostridium XIVa</em>, <em>Bacteroides</em> and <em>Lachnospiraceae</em>; cluster 2 and cluster 3 were more common post-transplantation with higher abundance of <em>Streptococcus</em> and <em>Staphylococcus</em> in the former whilst <em>Enterococcus</em>, <em>Enterobacteriaceae</em> and <em>Escherichia</em> predominated in the latter. Cluster 3 was also associated with a higher risk of viraemia. Likewise, further multivariate analysis reveals <em>Enterobacteriaceae</em>, viraemia, use of total parenteral nutrition and various antimicrobials contributing towards cluster 3, <em>Streptococcaceae</em>, <em>Staphylococcaceae</em>, <em>Neisseriaceae</em>, vancomycin and metronidazole contributing towards cluster 2. <em>Lachnospiraceae</em>, <em>Ruminococcaceae</em>, <em>Bifidobacteriaceae</em> and not being on total parenteral nutrition contributed to cluster 1. Untargeted metabolomic analyses revealed changes that paralleled fluctuations in microbiota composition; importantly, low fecal butyrate was associated with higher risk of viraemia.</p><p><strong>CONCLUSIONS:</strong> These findings highlight the frequent shifts and dominations in the gut microbiota of pediatric patients undergoing hematopoietic stem cell transplantation. The study reveals associations between the fecal microbiota, metabolome and viraemia. To identify and explore the potential of microbial biomarkers that may predict risk of complications post-HSCT, larger multi-centre studies investigating longitudinal microbial profiling in pediatric hematopoietic stem cell transplantation are warranted.</p>
Project description:The aim of this study is to assess the Fecal Microbiota Transplantation (FMT) efficacy in the prevention of allogeneic hematopoietic stem cell transplantation (allo-HSCT) complications and particularly Graft versus Host Disease (GvHD).
The hypothesis of this study is that allogeneic FMT may improve outcomes of these patients.
