The following article features coverage from the American Society of Hematology 2019 Annual Meeting. Click here to read more of Oncology Nurse Advisor‘s conference coverage.

Researchers used a computational approach to characterize the gut microbiota of patients who had undergone allogeneic hematopoietic stem cell transplantation (allo-HSCT), and they detected impacts on microbial community composition from dietary changes and antibacterial therapies. The study’s results were presented at the 61st American Society of Hematology (ASH) Annual Meeting & Exposition, held in Orlando, Florida.

According to the study investigators, the microbiota of patients often experience disruptions with allo-HSCT, and reduced microbial diversity may be associated with consequences such as graft-versus-host disease (GVHD).

In this study, the investigators performed DNA sequencing of 7930 samples from microbiomes of patients (N=1076) who had undergone allo-HSCT. The researchers fed the sequencing data into a clustering algorithm to evaluate patterns of diversity and composition in the microbial communities of these patients. The researchers used this algorithm to monitor changes in microbial communities with environmental modifiers that included antibacterial drugs and dietary alterations.

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Piperacillin-tazobactam (pip-tazo) exposure was reported to disrupt a microbial cluster (cluster 1) that had been characterized by high diversity (P <.05). This cluster, however, was not significantly impacted by cefepime and meropenem.

Pip-tazo was also associated with shifts toward a cluster dominated by Streptococcus (P <.001), while shifts toward an Enterococcus-dominated cluster appeared to be encouraged by exposure to cefepime (P <.05) or meropenem (P <.01).

Using specimens from 46 patients who provided dietary details, the investigators found that cluster 1, noted for high diversity, lost stability in the presence of more protein (P <.05), while a diet with a higher fat intake was associated with increased stability for this cluster (P <.05).

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The investigators stated that a goal of this approach to microbiota assessment, which evaluates entire microbial communities, is to help find treatments that enable optimal outcomes for patients undergoing allo-HSCT.

Disclosure: Multiple authors declared affiliations with industry. Please refer to the original abstract for a full list of disclosures.


Nguyen CL, Gomes ALC, Peled JU, et al. Antibiotic exposures and dietary intakes are associated with changes in microbiota compositions in allogeneic hematopoietic stem cell transplant patients. Oral presentation at: 61st ASH Annual Meeting & Exposition; December 7-10, 2019; Orlando, FL. Abstract 597.