Characterization of the gut phageome of Japanese patients with ulcerative colitis under endoscopic remission

This study aimed to analyze the gut phageome in Japanese patients with ulcerative colitis (UC) in endoscopic remission. Fecal samples were collected from 35 UC patients and 22 healthy controls. The gut microbiome was analyzed using 16S rRNA amplicon sequencing, and the phageome was profiled through shotgun metagenomic sequencing. Compared to healthy controls, UC patients showed a significant reduction in phageome richness (observed species and Chao1 index). Principal coordinate analysis revealed a significant difference in beta-diversity between UC and healthy controls (<i>p</i> = 0.001). The abundance of temperate phages was higher in UC (15.2%) compared to healthy controls (5.9%), although this was not statistically significant (<i>p</i> = 0.088). Temperate phages associated with <i>Coprococcus</i> sp., <i>Bacteroides</i> sp. KFT8, and <i>Faecalibacterium prausnitzii</i>, as well as virulent phages associated with <i>Ruminococcus gnavus</i> and <i>Lactobacillus farciminis</i>, were increased in UC patients. Conversely, phages associated with <i>Thermosipho affectus</i>, <i>Bacteroides</i> sp. OF03-11BH, and <i>Odoribacter splanchnicus</i> were decreased in UC patients. Phages associated with the genera <i>Odoribacter</i> (<i>p</i> = 0.0004), <i>Ruminococcus</i> (<i>p</i> = 0.009), and <i>Veillonella</i> (<i>p</i> = 0.013) were significantly reduced in UC patients. The gut phageome of inactive UC patients exhibited notable alterations in viral composition compared to healthy controls. These results suggest that changes in the gut phageome might be involved in the pathogenesis of UC.