The gut virome is temporally stable, can be affected by diet, and may influence host function via interactions with gut bacteria and/or altering host gene expression, according to a study in Gastroenterology.

Researchers used enrichment of viral-like particles, sequence amplification, and bioinformatics combined with multi-omics and dietary data to assess the stability of the virome over time, the effect of diet and genetics on the virome, the impact of the virome on host gene expression, and whether specific viruses are associated with subtypes of irritable bowel syndrome (IBS).

The included sample population was taken from a larger observational, multi-omics study of patients with IBS and healthy controls. Each participant provided a stool sample every month and 1 additional sample during a self-identified flare in symptoms between the collections.

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The analysis included 16 healthy control participants (mean age, 37.44 years; 12 women), 17 patients with IBS constipation-predominant (IBS-C) (mean age, 43.12 years; 16 women), and 17 patients with IBS diarrhea-predominant (IBS-D) (mean age, 38.18 years; 13 women). The groups were matched for sex, and there were no significant differences in age (P =.439, ANOVA) and body mass index (P =.918, ANOVA). Two consecutive stool samples from each participant were selected for virome analysis.

The investigators found that the relative closeness of the samples from the same individual compared with samples from other participants demonstrated stability of the intestinal virome within an individual.

Significant correlations were observed between dark matter and phage population in terms of bacterial composition. Disease subset-specific changes in phage population were also found, with phage species within the Microviridae, Myoviridae, and Podoviridae families increased in patients with IBS-D, and other Microviridae and Myoviridae species increased in patients with IBS-C, compared with healthy control participants. Other Microviridae, Podoviridae, and Siphoviridae families were differentially abundant between IBS-D and IBS-C, according to the study authors.

Multi-omics integration using correlation analysis showed fewer significant correlations of eukaryotic viruses with bacterial composition compared with phages, which was expected, as bacteria are not hosts for eukaryotic viruses. This result may also be due to the presence of fewer eukaryotic viruses in the dataset. However, the investigators observed correlations between plant viruses and diet, which is consistent with diet as a source of eukaryotic viruses.

Significant correlations were also found between plant viruses and food categories within each group of participants, and these were more prominent in patients with IBS-C. This may be attributed to specific dietary intake or an altered microbial ecosystem.

One study limitation is that the relatively small sample size in each group precluded a subset-specific assessment of the impact of the virome on the host transcriptome.

“Identification of IBS-subset phage populations [that] correlated with gut bacteria suggest a potential role for gut virome in pathogenesis of IBS and efficacy of bacteriotherapy,” stated the researchers.

Disclosure: Some of the study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.


Mihindukulasuriya KA, Mars RAT, Johnson AJ, et al. Multi-omics analyses show disease, diet, and transcriptome interactions with the virome. Gastroenterol. Published online July 7, 2021. doi: 10.1053/j.gastro.2021.06.077