Faecalicatena contorta

What a Faecalicatena contorta test measures

A microbiome analysis can assign DNA sequences in stool to this bacterial species and estimate its relative abundance. That is not a direct count of living bacteria. How confidently the species can be identified depends partly on the sequencing method and reference databases. A 16S analysis cannot always distinguish closely related species reliably; metagenomic methods can provide more detail. Comparison of methods

Faecalicatena contorta was previously called Eubacterium contortum and belongs to the Lachnospiraceae family. The taxonomic paper describes how the species is classified; it does not validate a health test. The genus includes anaerobic bacteria that use carbohydrates and produce acetate, among other substances, under laboratory conditions. Sakamoto and colleagues

One particularly interesting research direction concerns bile acid metabolism. A 2026 experimental study compared an F. contorta strain with a genetically modified version lacking a specific conversion pathway. In a mouse model of colorectal cancer, the modified strain was associated with fewer tumors. Human intestinal organoids also showed less cell proliferation than with the original strain. This supports a role for the secondary bile acids produced through that pathway in these models. It does not turn a stool abundance result into a personal cancer risk test or justify trying to eliminate the bacterium yourself. Experimental study

What measuring one Lachnospiraceae species can tell us

In research, measuring individual species can help scientists explore relationships with diet or disease. For personal care, the central question is whether a result leads to a decision that demonstrably helps. The sources reviewed here do not establish that for Faecalicatena contorta.

Findings about the Lachnospiraceae family as a whole are mixed and cannot be applied to every species or strain. A low or high abundance therefore does not automatically explain bloating, skin rashes, mood, or immune responses. Review of Lachnospiraceae

For ongoing digestive symptoms, an assessment guided by those symptoms is more useful than trying to move this species toward a supposed target value.

Understanding the number on your report

Most reports give a relative abundance. That percentage can rise because other microbes decline, without Faecalicatena contorta itself becoming more numerous. A comparison with a reference group initially describes only a difference between samples.

There is no established clinical optimal range for this species. A laboratory’s “typical” range is therefore not proof of an intact gut barrier or healthy fatty acid production. Diversity alone is not a certificate of good health either. The international consensus advises against claiming strict healthy reference ranges for the relative abundance of individual species. Consensus statement

A species’ abundance cannot reliably reveal the quantity or activity of a metabolic product. Even detecting relevant genes initially shows a potential capability, rather than the pathway’s actual activity in the gut.

What the test can and cannot do

The test can provide a snapshot of which organisms are represented. It does not establish the cause of symptoms or identify which dietary change will help an individual. Adding blood tests does not turn an unvalidated species profile into a validated guide to treatment. Further investigations should follow the symptoms and the clinical question.

Frequently asked questions

What does a Faecalicatena contorta test measure?

It is usually part of a DNA-based microbiome analysis. A 16S method examines bacterial marker genes; it does not automatically measure fungi, RNA, resistance genes, or the community’s entire functional potential. The particular test should state what information it actually collects.

How is a sample collected?

You collect stool, not the bacterial species itself. Use the supplied container, avoid contact with urine or toilet water, and follow the laboratory’s instructions for storage and shipping. Wash your hands before and after collection. Careful sampling matters, but it does not remove the limits of clinical interpretation.

What can the result tell me about my health?

It can describe whether the test finds sequences assigned to the species and what proportion they represent. That number alone cannot determine nutrient absorption, inflammation, gut-brain communication, or the presence of a disease. Researchers continue to investigate the underlying biological relationships.

How accurate and reliable are these tests?

There is no defensible single accuracy figure without details of the method. Sequencing depth, sample processing, and databases all affect the result. Detecting DNA and demonstrating clinical usefulness are separate questions. The cited comparison found advantages for metagenomic methods in measuring species diversity, but it did not validate a Faecalicatena contorta test.

How often should I test Faecalicatena contorta?

There is no established general retesting interval. The reviewed sources do not support recommending either annual tests or routine checks every few months. Repeat measurements may be useful for a clearly defined research or clinical question; an unusual individual result does not automatically justify them.

Can Faecalicatena contorta populations change quickly?

The composition of the microbiome can fluctuate. For this particular species, however, the reviewed sources do not establish a fixed time after which a stable new baseline appears. Do not change your diet or medication specifically for a test unless your care team recommends it.

Are the results diagnostic?

No. An isolated abundance value does not diagnose a particular disease or a clinically defined “imbalance.” When symptoms are present, medical history, examination, and targeted tests suited to the question are what matter.

How can I support Faecalicatena contorta after testing?

There is no strategy validated against this measurement for moving the species toward a healthy target value. The result does not establish which prebiotic, probiotic, or dose to choose.

A varied diet that you tolerate remains worthwhile without a microbiome test. If you change your fiber intake, you can observe how your symptoms and bowel habits respond. Persistent symptoms deserve assessment, rather than choosing supplements solely from a laboratory profile.

Sources and further reading

• Sakamoto M, Iino T, Ohkuma M (2017). Faecalimonas umbilicata gen. nov., sp. nov., isolated from human faeces, and reclassification of Eubacterium contortum, Eubacterium fissicatena and Clostridium oroticum as Faecalicatena contorta gen. nov., comb. nov., Faecalicatena fissicatena comb. nov. and Faecalicatena orotica comb. nov. International Journal of Systematic and Evolutionary Microbiology, 67(5), 1219-1227. https://doi.org/10.1099/ijsem.0.001790 Source

• Vacca M, Celano G, Calabrese FM, Portincasa P, Gobbetti M, De Angelis M (2020). The controversial role of human gut Lachnospiraceae. Microorganisms, 8(4), 573. https://doi.org/10.3390/microorganisms8040573 Source

• Parada Venegas D, De la Fuente MK, Landskron G, González MJ, Quera R, Dijkstra G, Harmsen HJM, Faber KN, Hermoso MA (2019). Short chain fatty acids (SCFAs)-mediated gut epithelial and immune regulation and its relevance for inflammatory bowel diseases. Frontiers in Immunology, 10, 277. https://doi.org/10.3389/fimmu.2019.00277 Source

• Laudadio I, Fulci V, Palone F, Stronati L, Cucchiara S, Carissimi C (2018). Quantitative assessment of shotgun metagenomics and 16S rDNA amplicon sequencing in the study of human gut microbiome. OMICS, 22(4), 248-254. https://doi.org/10.1089/omi.2018.0013 Source

• Porcari S et al. (2025). International consensus statement on microbiome testing in clinical practice. The Lancet Gastroenterology & Hepatology, 10(2), 154-167. https://doi.org/10.1016/S2468-1253(24)00311-X Source

• Osswald A et al. (2026). Secondary bile acid production by gut bacteria promotes Western diet-associated colorectal cancer. Gut, 75, 1505–1519. https://doi.org/10.1136/gutjnl-2024-332243