Gut microbiota profiles of treatment-naïve adult acute myeloid leukemia patients with neutropenic fever during intensive chemotherapyOriginal paper
Karen Pendergrass is a microbiome researcher specializing in microbiome-targeted interventions (MBTIs). She systematically analyzes scientific literature to identify microbial patterns, develop hypotheses, and validate interventions. As the founder of the Microbiome Signatures Database, she bridges microbiome research with clinical practice. In 2012, based on her own investigative research, she became the first documented case of FMT for Celiac Disease, four years before the first published case study.
Read MoreWhat was studied?
This study tracked how gut bacteria change in adults with acute myeloid leukemia who develop neutropenic fever during their first intensive chemotherapy. Stool was sampled at three timepoints: before treatment, at the first day of neutropenic fever, and at bone marrow recovery. Bacterial DNA was extracted from stool and the 16S rRNA V3-V4 region sequenced by next-generation sequencing. Relative abundance, richness by operational taxonomic units, and Shannon and Simpson diversity indices were calculated. No antibiotic prophylaxis was used before fever onset.
Who was studied?
The cohort was 10 consecutive treatment-naive Thai adults with acute myeloid leukemia, 4 male and 6 female, median age 39 years (range 19 to 49). All were treated at Chiang Mai University hospital. Every patient received standard 7 plus 3 induction chemotherapy and developed febrile neutropenia. Piperacillin/tazobactam was the first empirical antibiotic in all cases. In total, 24 stool samples were collected: 10 pretreatment, 9 at febrile neutropenia, and 5 at bone marrow recovery. Missing samples were due to technical issues.
What were the most important findings?
During neutropenic fever the phylum Firmicutes dominated, rising from a median 34.3 percent to 50.8 percent, then declined after marrow recovery. Bacteroidetes and Proteobacteria showed the opposite pattern. Enterococcus rose sharply during fever versus pretreatment (mean difference plus 20.2; p less than 0.0001), while Escherichia fell (mean difference minus 11.2; p equals 0.0064). Richness dropped from a mean 203.1 to 131.7 operational taxonomic units (p equals 0.012). Both Shannon and Simpson diversity fell significantly during fever and stayed low despite marrow recovery.
What are the greatest implications of this study?
The findings suggest that even a first cycle of intensive chemotherapy, without antibiotic prophylaxis, drives major loss of gut microbial diversity in acute myeloid leukemia. Diversity did not recover with bone marrow recovery. Enterococcus expansion during fever echoes prior reports linking this genus to infectious complications. Loss of diversity may help predict and manage such complications. The sample was small (10 patients) with missing timepoints, limiting statistical power. Larger multicenter studies are needed before clinical use in antibiotic decisions.