Gut microbiome in allogeneic hematopoietic stem cell transplantation and specific changes associated with acute graft vs host disease

Table 1 Gut microbiome diversity, composition and function changes in gut microbiota during allogeneic hematopoietic stem cell transplantation procedure

Ref.	Sequencing technology	Change in diversity	Changes in composition	Change in functions
Peled et al[15]	16S rRNA gene-based amplicon sequence	Loss of diversity	Gut microbiota dominate by single taxa (occupation of at least 30% of the gut microbiota by a single predominating bacterial taxon), including Enterococcus, Streptococcus, Enterobacteriaceae (Escherichia and Kluyvera), and Lactobacillus
Taur et al[16]	16S rRNA gene-based amplicon sequence	Decrease of the gut microbiome diversity index	Gut microbiota composition frequently dominated by a single bacterial taxon, including Enterococcus, Streptococcus or Proteobacteria
Ilett et al[10]	Metagenomic shotgun	Loss of gut microbiota diversity	Post-aHSCT samples enriched in Staphylococcus, Eggerthella, Streptococcus, Enterococcus and Lactobacillus compared to pre-aHSCT samples, &t species level enrichment in Enterococcus faecium, Lactobacillus delbrieckii, Staphylococcus epidermidis, and Streptococcus thermophilus
Montassier et al[19]	16S rRNA gene-based amplicon sequence	Loss of gut microbiota diversity	Decreases in abundances of Firmicutes and Actinobacteria, and significant increases in abundances of Proteobacteria	Reduced capacity for nucleotide metabolism, energy metabolism, metabolism of cofactors and vitamins, and increased capacity for glycan metabolism, signal transduction and xenobiotics biodegradation

HSCT: Hematopoietic stem cell transplantation.