Vernon, Suzanne D, Shukla, Sanjay K, Conradt, Jennifer et al. · BMC microbiology · 2002 · DOI
Researchers tested whether bacteria in the bloodstream might be linked to ME/CFS by analyzing blood samples from people with ME/CFS and healthy controls. They found that healthy people had more detectable bacterial DNA in their blood than ME/CFS patients did, and no unique or unusual bacteria were found in either group. This suggests that a specific bacterial infection is unlikely to be a primary cause of ME/CFS.
This study directly addressed whether a hidden bacterial infection might explain ME/CFS symptoms. The results help rule out a straightforward bacterial infection model, redirecting research toward understanding why ME/CFS patients show different plasma DNA patterns and encouraging investigation of other potential mechanisms.
This study does not prove bacteria are completely uninvolved in ME/CFS—it only shows that a single dominant bacterial pathogen in the bloodstream is unlikely. The cross-sectional design cannot establish causation, and the diverse bacterial sequences detected may still reflect disease-related changes rather than causal agents. The absence of a 'unique' pathogen does not exclude roles for altered microbial communities or dysbiosis.
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
Vernon, Suzanne D, Shukla, Sanjay K, Conradt, Jennifer, Unger, Elizabeth R, & Reeves, William C (2002). Analysis of 16S rRNA gene sequences and circulating cell-free DNA from plasma of chronic fatigue syndrome and non-fatigued subjects.. BMC microbiology. https://doi.org/10.1186/1471-2180-2-39
BibTeX
@article{mecfsatlas-vernon-2002-analysis-16s,
author = {Vernon, Suzanne D and Shukla, Sanjay K and Conradt, Jennifer and Unger, Elizabeth R and Reeves, William C},
title = {Analysis of 16S rRNA gene sequences and circulating cell-free DNA from plasma of chronic fatigue syndrome and non-fatigued subjects.},
journal = {BMC microbiology},
year = {2002},
doi = {10.1186/1471-2180-2-39},
note = {PubMed: 12498618},
url = {https://www.mecfsatlas.com/evidence/vernon-2002-analysis-16s},
}Atlas snapshot reference
ME/CFS Atlas. Generator v1 / Scanner v1.4 / policy v0.1. Accessed 2026-05-30. https://www.mecfsatlas.com/evidence/vernon-2002-analysis-16s
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