Pilot study investigating the effect of enteral and parenteral nutrition on the gastrointestinal microbiome post‐allogeneic transplantation

Nutrition support is frequently required post-allogeneic haematopoietic progenitor cell transplantation (HPCT); however, the impact of mode of feeding on the gastrointestinal microbiome has not been explored. This study aimed to determine if there is a difference in the microbiome between patients receiving enteral nutrition (EN) and parenteral nutrition (PN) post-allogeneic HPCT. Twenty-three patients received either early EN or PN when required. Stool samples were collected at 30 days post-transplant and analysed with shotgun metagenomic sequencing. There was no difference in microbial diversity between patients who received predominantly EN (n = 13) vs. PN (n = 10) however patients who received predominantly EN had greater abundance of Faecalibacterium (P < 0.001) and ruminococcus E bromii (P = 0.026). Patients who had minimal oral intake for a longer duration during provision of nutrition support had a different overall microbial profile (P = 0.044), lower microbial diversity (P = 0.004) and lower abundance of faecalibacterium prausnitzii_C (P = 0.030) and Blautia (P = 0.007) compared to patients with greater oral intake. Lower microbial diversity was found in patients who received additional beta lactam antibiotics (P = 0.042) or had a longer length of hospital stay (P = 0.019). Post-HPCT oral intake should be encouraged to maintain microbiota diversity and, if nutrition support is required, EN may promote a more optimal microbiota profile