After years of collecting patient histories, correspondence, and laboratory reports, one impression has become increasingly difficult to ignore: there may not be one single underlying cause of PATM or MEBO. Instead, different people may arrive at a similar set of symptoms through different biological pathways.
We do have a growing list of possible culprits and triggers, and we are beginning to see that some patients can be matched by particular findings. But it remains a list—with many different candidates rather than one universal explanation.
Last week, for example, we received a letter from a young woman in the United States who had experienced MEBO for approximately a decade. She was only recently diagnosed with biliary dyskinesia, a disorder affecting the movement of bile from the gallbladder.
This is not the first story of this type that we have encountered. In the past, we heard from a young man in China who had experienced PATM for approximately eight years and from a 37-year-old man in the United States who reported having PATM since he was 14. Both suspected problems with their gallbladder as a culprit.
These stories align with our observation that disturbances in different parts of the gastrointestinal system may sometimes contribute to a similar downstream phenomenon.
And then today, we received another intriguing history, this time from a man in Finland.
He believes that his PATM began following exposure to a water-damaged building and that Fusarium, a genus of fungi, may be involved. Fusarium odoratissimum are explicitly named for their potent, recognizable odor and many strains produce damp, musty unpleasant smells. He subsequently had testing that detected mycotoxins associated with Fusarium, and he has developed a detailed hypothesis connecting fungal metabolism, intestinal processes, volatile organic compounds (VOCs), and the reactions experienced by people around him. This aligns with several other stories linked to mycotoxins, although those patients did not test specifically for fungi in their systems.
His interpretation is still a hypothesis. Nevertheless, Fusarium is another candidate that deserves to be investigated.
Fungi and yeasts are still relatively understudied compared with bacteria, particularly when it comes to the human microbiome and gastrointestinal ecosystem.
At the same time, laboratory technology continues to evolve. Testing methods are becoming more sophisticated, and laboratories are expanding the range of microorganisms and metabolites they can detect.
That matters because what we are able to find depends, to some extent, on what we know how to look for.
The Finnish patient's testing was performed by Great Plains Laboratory, the same laboratory used by several other people in the PATM/MEBO community—along with Metametrix, Genova Diagnostics, Viome, and Biohm. We have not yet found one microorganism that is consistently present across all of these cases.
Interestingly, however, there are already some preliminary overlaps.
For example, among the people whose histories and laboratory results we have examined, Citrobacter freundii and E. coli have appeared in more than one case. These findings are far too limited to establish causation - both organisms can be found in the human gastrointestinal tract of individuals not reporting MEBO/PATM issues - but repeated observations are worth documenting and investigating.
Our microbiome study provides another piece of the puzzle. Using 16S rRNA sequencing, we found several microorganisms that appeared in common among participants. Some of these may represent opportunistic organisms or secondary changes resulting from another underlying disturbance, meaning that we may have been observing consequences rather than the original cause. I will be sharing more data from this study separately, but one important finding was the remarkably high heterogeneity among participants. Even with approximately 100 participants, the sample was not large enough to overcome that heterogeneity and identify a single consistent microbial signature.
This is another reason why I am increasingly hesitant to look for one universal culprit. The microorganisms we detect may sometimes be part of the downstream effects of whatever initially disrupted the individual's gastrointestinal ecosystem.
And Fusarium gives us yet another direction to explore.
PATM appears not to be a single disease with a single pathogen, but rather an umbrella for several conditions, just as similar symptoms in other medical conditions can arise from very different underlying problems.
One person might have a disorder affecting bile flow. Another might have bacterial dysbiosis. Another might have fungal involvement. Another might have a different gastrointestinal, metabolic, or systemic problem that we have not yet identified.
The common denominator may therefore not be the original cause, but rather what happens downstream.
Different disturbances could potentially alter the intestinal environment, microbiome, metabolism, or the volatile compounds released by the body. If those downstream changes are capable of producing similar external effects, they could potentially lead to what patients experience as PATM or MEBO.
Patient histories are not clinical trials, and an association between two findings does not establish causation. We also have to be careful with laboratory tests: detecting an organism, metabolite, or mycotoxin does not automatically tell us where it came from or whether it is responsible for someone's symptoms.
Nevertheless, patterns are worth recording.
If the same organism appears repeatedly in unrelated patients, that deserves investigation. If several people improve after treatment of a particular gastrointestinal disorder, that deserves investigation. If a fungal organism repeatedly appears in patients with similar symptoms, that deserves investigation too.
And if entirely different medical conditions appear to precede the same phenomenon, that may be an important clue in itself.
For now, our list remains a list.
But we might eventually map it to the different pathways that can lead to the PATM/MEBO phenomenon and to what those pathways have in common.
REFERENCES
Gabashvili IS Cutaneous Bacteria in the Gut Microbiome as Biomarkers of Systemic Malodor and People Are Allergic to Me (PATM) Conditions: Insights From a Virtually Conducted Clinical Trial JMIR Dermatol 2020;3(1):e10508
URL: https://derma.jmir.org/2020/1/e10508
DOI: 10.2196/10508
MEBO and PATM--associated multispecies microbiomes mostly from stool, but also skin, oral, nasal, and genital sites https://www.ncbi.nlm.nih.gov/sra?linkname=bioproject_sra_all&from_uid=1413303
Ledoux, M.-P., Dicop, E., Sabou, M., Letscher-Bru, V., Castelain, V., Danion, F., & Herbrecht, R. (2024). Fusarium, Scedosporium and Other Rare Mold Invasive Infections: Over Twenty-Five-Year Experience of a European Tertiary-Care Center. Journal of Fungi, 10(4), 289. https://doi.org/10.3390/jof10040289
