Intestinal microbiome changes and stem cell transplantation: Lessons learned

Figures & data

Figure 1. Significant microbiome findings in stem cell transplantation. A phylogenetic tree of intestinal bacterial species is shown. Results of microbiome studies in SCT recipients is summarized; bacterial clades (dotted lines with shading) are shown at various levels of taxonomic classification. Highlighted clades summarize the findings of each study (blue shading denotes association with beneficial effects, red shading denotes association with negative effects).

Table 1. Ongoing Challenges and Future Questions.

Do differences in the microbiota at different sites within the gut matter? (e.g., oral cavity vs. small intestine vs. large intestine)

What is the role of fungi and viruses in the gut microbiome (i.e. mycobiome and virome, respectively)? Do they offer host benefits similar to bacteria?

What is the impact of the microbiome on relapse of the recipient's underlying malignancy?

Regarding intestinal domination, are the increases in relative abundance truly related to expansion of the pathogen, or more due to inhibition and killing of beneficial microbe populations? Is absolute abundance more informative than relative abundance?

Does the stem cell donor's microbiome have any association with the recipient's miocrobiome?

Would other ‘omic’ platforms such as transcriptomics or metabolomics shed further light on the details of host-microbe interactions?

How should these findings inform antibiotic use in SCT patients?

Can disrupted microbiota populations be restored, through fecal microbiota transplantation or bacteriotherapy with defined bacterial consortia? Can this lead to improved transplant outcomes?