Identification of novel Carnobacterium maltaromaticum strains in bone marrow samples of patients with acute myeloid leukemia using a metagenomic binning approach

The aim of this study aimed to examine the existence of a bacterial metagenome in the bone marrow of patients with acute myeloid leukemia (AML). We re-examined whole-genome sequencing data from the bone marrow samples of seven patients with AML, four of whom were remitted after treatment, for metagenomic analysis. After the removal of human reads, unmapped reads were used to profile the species-level composition. We used the metagenomic binning approach to confirm whether the identified taxon was a complete genome of known or novel strains. We observed a unique and novel microbial signature in which Carnobacterium maltaromaticum was the most abundant species in five patients with AML or remission. The complete genome of C. maltaromaticum “BMAML_KR01,” which was observed in all samples, was 100% complete with 8.5% contamination and closely clustered with C. maltaromaticum strains DSM20730 and SF668 based on single nucleotide polymorphism variations. We identified five unique proteins that could contribute to cancer progression and 104 virulent factor proteins in the BMAML_KR01 genome. To our knowledge, this is the first report of a new strain of C. maltaromaticum in patients with AML. The presence of C. maltaromaticum and its new strain in patients indicates an urgent need to validate the existence of this bacterium and evaluate its pathophysiological role.