Characterization of microbiota in acute leukemia patients following successful remission induction chemotherapy without antimicrobial prophylaxis

In the present study, we characterized the microbiomes of acute leukemia (AL) patients who achieved complete remission following remission induction chemotherapy (RIC) as outpatients, but who did not receive antimicrobials to treat or prevent febrile neutropenia. Saliva and stool samples from 9 patients with acute myeloid leukemia, 11 patients with acute lymphoblastic leukemia, and 5 healthy controls were subjected to 16S ribosomal RNA sequencing at baseline and at 3 months following RIC. Only patients who achieved remission at 3 months post-treatment were included. We excluded anyone who used antimicrobials within 2 months of enrollment or at any time during the study period. At baseline, the relative abundances of species of Prevotella maculosa (P=0.001), Megasphaera micronuciformis (P=0.014), Roseburia inulinivorans (P=0.021), and Bacteroides uniformis (P=0.004) in saliva and Prevotella copri (P=0.002) in the stools of controls were significantly higher than in AL patients. Following RIC, the relative abundances of Eubacterium sp. oral clone DO008 (P=0.012), Leptotrichia sp. oral clone IK040 (P=0.002), Oribacterium sp. oral taxon 108 (P=0.029), Megasphaera micronuciformis (P=0.016), TM7 phylum sp. oral clone DR034 (P