Taxonomic variations in the gut microbiome of patients with gout with and without tophi might have a functional impact on urate metabolism, according to a study published in Molecular Medicine. To evaluate the taxonomic composi- tion of the gut microbiome in this patient popul- ation and predict bacterial functions that may im- pact urate metabolism, investigators sequenced hypervariable V3-V4 regions of the bacterial 16S rRNA gene from fecal samples of patients with gout with and without tophi and compared them with samples from healthy controls. When compared with controls, patients with gout with- out tophi had a microbiome characterized by the lowest richness and a higher abundance of Phascolarctobacterium, Bacteroides, Akkermansia, and Ruminococcus gnavus group genera in patients with gout without tophi, whereas the Proteobac- teria phylum and Escherichia-Shigella genus were more abundant in patients with tophaceous gout. Patients with both types of gout had core micro- biota that included Bacteroides caccae, Bacteroides stercoris ATCC 43183, and Bacteroides coprocola DSM 17136, which may perform functions linked to one-carbon metabolism, nucleotide binding, amino acid biosynthesis, and purine biosynthesis. Differences were also observed in key bacterial enzymes involved in urate synthe- sis, degradation, and elimination.
