The taxonomic distribution of histamine-secreting bacteria in the human gut microbiome.

ABSTRACT

BACKGROUND: Biogenic histamine plays an important role in immune response, neurotransmission, and allergic response. Although endogenous histamine production has been extensively studied, the contributions of histamine produced by the human gut microbiota have not been explored due to the absence of a systematic annotation of histamine-secreting bacteria. RESULTS: To identify the histamine-secreting bacteria from in the human gut microbiome, we conducted a systematic search for putative histamine-secreting bacteria in 36,554 genomes from the Genome Taxonomy Database and Unified Human Gastrointestinal Genome catalog. Using bioinformatic approaches, we identified 117 putative histamine-secreting bacteria species. A new three-component decarboxylation system including two colocalized decarboxylases and one transporter was observed in histamine-secreting bacteria among three different phyla. We found significant enrichment of histamine-secreting bacteria in patients with inflammatory bowel disease but not in patients with colorectal cancer suggesting a possible association between histamine-secreting bacteria and inflammatory bowel disease. CONCLUSIONS: The findings of this study expand our knowledge of the taxonomic distribution of putative histamine-secreting bacteria in the human gut.