Brigo, Natascha, Mayr, Wolfram, Taenzer, Maja et al. · Frontiers in cellular and infection microbiology · 2025 · DOI
This small study looked at special waste products made by gut bacteria in the urine of people with long COVID, ME/CFS, and healthy people. Researchers found that people with long COVID and ME/CFS had different patterns of these bacterial products compared to healthy controls, and these patterns might be connected to their symptoms like fatigue and post-exertional malaise (feeling much worse after activity).
This research addresses a critical knowledge gap about what causes ME/CFS and post-COVID symptoms by examining gut bacteria and their metabolic byproducts. If gut dysbiosis is confirmed as a contributing factor, it could lead to new diagnostic tests and treatments targeting the microbiome for ME/CFS patients.
This study does not prove that elevated bacterial metabolites cause ME/CFS or post-COVID symptoms—it only shows an association. The small sample size and pilot nature mean findings require replication in larger studies before clinical application. The cross-sectional design cannot establish whether dysbiosis is a cause, consequence, or coincidental feature of these conditions.
About the PEM badge: “PEM required” means post-exertional malaise was an explicit required diagnostic criterion for participant inclusion in this study — not that PEM was studied, observed, or discussed. Studies using criteria that do not require PEM (e.g. Fukuda, Oxford) are tagged “PEM not required”. How the atlas works →
The first block is for the primary paper and is the citation you should use in research work. The atlas-snapshot line only applies if you are specifically referring to this atlas’s reading of the paper on the date shown.
Primary citation
Brigo, Natascha, Mayr, Wolfram, Taenzer, Maja, Löffler-Ragg, Judith, Schroll, Andrea, Engl, Sabine, et al. (2025). Concentrations of uremic bacterial metabolites in patients with post-COVID-19 syndrome.. Frontiers in cellular and infection microbiology. https://doi.org/10.3389/fcimb.2025.1582972
BibTeX
@article{mecfsatlas-brigo-2025-concentrations-uremic,
author = {Brigo, Natascha and Mayr, Wolfram and Taenzer, Maja and Löffler-Ragg, Judith and Schroll, Andrea and Engl, Sabine and Schütz, Burkhard and Rappl, Peter and Heine, Till and Weiss, Günter and Kurz, Katharina},
title = {Concentrations of uremic bacterial metabolites in patients with post-COVID-19 syndrome.},
journal = {Frontiers in cellular and infection microbiology},
year = {2025},
doi = {10.3389/fcimb.2025.1582972},
note = {PubMed: 40510799},
url = {https://www.mecfsatlas.com/evidence/brigo-2025-concentrations-uremic},
}Atlas snapshot reference
ME/CFS Atlas. Generator v1 / Scanner v1.4 / policy v0.1. Accessed 2026-05-27. https://www.mecfsatlas.com/evidence/brigo-2025-concentrations-uremic
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