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Christensenella is a genus of non-spore-forming, anaerobic, and nonmotile bacteria from the family Christensenellaceae. They are also part of the order Clostridiales, the class Clostridia and the phylum Firmicutes. Phylogenetic analyzes of 16S rRNA gene sequences are used to describe this family. Due to the recent discovery of the Christensenellaceae family, it was not given importance until a few years ago. This is why very little is known about its ecology and how it may be associated with host factors and other microbiota. However, recent studies establish that members of this family, with exceptions, may be associated with a healthy phenotype for humans. The species C. minuta has been published and validated, and C. timonensis and C. massiliensis have been proposed as novel species of the genus Christensenella, all isolated from human feces.

Characteristics (health-related group)

Some of the most relevant features are:

• It has been detected in the mucosa of the colon, ileum and appendix, and there is also evidence of colonization of the respiratory tract. It has a probable preference for the distal colon, which corresponds to its fermentative activities. In humans, this family corresponds to an average of 0.01% of the fecal microbiota.
• It has been associated with human longevity. We found a greater amount in centenarians compared to younger individuals.
• It is identified as one of the most heritable.
• Individuals with a normal body mass index (BMI) have a higher number of Christensenellaceae than obese individuals; if these are put on a diet, the Christensenellaceae increases after weight loss.
• Its proportion increases when triglyceride levels are low and high-density lipoprotein (HDL or "cholesterol" levels) are high.
• It has been associated with healthy glucose metabolism. It is also related to the consumption of dairy products and the fermentation of proteins and fibers. It has a greater abundance in omnivores compared to vegetarians, since it responds quickly to an increase in animal products in the diet.
• Individuals with Crohn's disease and ulcerative colitis depleted Christensenellaceae.

Christensenella minuta

C. minuta was the first species described in the new family Christensenellaceae in 2012 by Morotomi et al. According to research performed on healthy volunteers in 2014, the bacterium was identified as the most heritable gut microbe in humans, in which its presence is mainly determined by genetic background. C. minuta seems to play a major role in the development of a healthy gut microbiome coexisting with other important microbes, and missing in many chronically ill patients.

C. minuta in the gut has been associated with reduction in body weight and adiposity of mice. In a test on 977 volunteers, humans with higher levels of Christensenella in their guts were found to be more likely to have a lower body mass index than those with low levels. Christensenella are better represented in persons who are metabolically healthy. However, there is a link to possible pathogenic qualities of C. minuta in humans. An 18-year-old male presented with symptoms of appendicitis. Lab work revealed C. minuta was found in his bloodstream. Upon removal of the appendix, his symptoms and blood levels of C. minuta disappeared.

Christensenella intestinihominis

Christensenella timonensis

References

1. Morotomi, Masami; Nagai, Fumiko; Watanabe, Yohei (2012). "Description of Christensenella minuta gen. nov., sp. nov., isolated from human faeces, which forms a distinct branch in the order Clostridiales, and proposal of Christensenellaceae fam. nov". International Journal of Systematic and Evolutionary Microbiology. 62 (1): 144–149. doi:10.1099/ijs.0.026989-0. ISSN 1466-5034. PMID 21357455.
2. Waters, Jillian L.; Ley, Ruth E. (2019-10-28). "The human gut bacteria Christensenellaceae are widespread, heritable, and associated with health". BMC Biology. 17 (1): 83. doi:10.1186/s12915-019-0699-4. ISSN 1741-7007. PMC 6819567. PMID 31660948. This article incorporates text from this source, which is available under the CC BY 4.0 license.
3. Waters JL, Ley RE (October 2019). "The human gut bacteria Christensenellaceae are widespread, heritable, and associated with health". BMC Biology. 17 (1): 83. doi:10.1186/s12915-019-0699-4. PMC 6819567. PMID 31660948.
4. Lim JM, Letchumanan V, Tan LT, Hong KW, Wong SH, Ab Mutalib NS, et al. (August 2022). "Ketogenic Diet: A Dietary Intervention via Gut Microbiome Modulation for the Treatment of Neurological and Nutritional Disorders (a Narrative Review)". Nutrients. 14 (17): 3566. doi:10.3390/nu14173566. PMC 9460077. PMID 36079829.
5. Goodrich JK, Waters JL, Poole AC, Sutter JL, Koren O, Blekhman R, et al. (November 2014). "Human genetics shape the gut microbiome". Cell. 159 (4): 789–799. doi:10.1016/j.cell.2014.09.053. PMC 4255478. PMID 25417156.
6. Liu X, Sutter JL, de la Cuesta-Zuluaga J, Waters JL, Youngblut ND, Ley RE (April 2021). "Reclassification of Catabacter hongkongensis as Christensenella hongkongensis comb. nov. based on whole genome analysis". International Journal of Systematic and Evolutionary Microbiology. 71 (4): 004774. doi:10.1099/ijsem.0.004774. PMC 8289216. PMID 33881979.
7. Morotomi M, Nagai F, Watanabe Y (January 2012). "Description of Christensenella minuta gen. nov., sp. nov., isolated from human faeces, which forms a distinct branch in the order Clostridiales, and proposal of Christensenellaceae fam. nov". International Journal of Systematic and Evolutionary Microbiology. 62 (Pt 1): 144–149. doi:10.1099/ijs.0.026989-0. PMID 21357455.
8. ^ Pető Á, Kósa D, Szilvássy Z, Fehér P, Ujhelyi Z, Kovács G, Német I, Pócsi I, Bácskay I (August 2023). "Scientific and Pharmaceutical Aspects of Christensenella minuta, a Promising Next-Generation Probiotic". Fermentation. 9 (8): 767. doi:10.3390/fermentation9080767. ISSN 2311-5637.
9. Waters JL, Goodrich JK, Ley RE. "The human gut bacterium Christensenella minuta reduces weight and adiposity gains in mice" (PDF). Department of Molecular Biology and Genetics, Department of Microbiology, Cornell University.
10. Goodrich JK, Waters JL, Poole AC, Sutter JL, Koren O, Blekhman R, et al. (November 2014). "Human genetics shape the gut microbiome". Cell. 159 (4): 789–799. doi:10.1016/j.cell.2014.09.053. PMC 4255478. PMID 25417156.
11. Hamzelou J (6 November 2014). "Composition of your gut bacteria may be inherited". New Scientist. Retrieved 28 July 2016.
12. ^ Stenman LK, Burcelin R, Lahtinen S (February 2016). "Establishing a causal link between gut microbes, body weight gain and glucose metabolism in humans - towards treatment with probiotics". Beneficial Microbes. 7 (1): 11–22. doi:10.3920/BM2015.0069. PMID 26565087.
13. Alonso BL, Irigoyen von Sierakowski A, Sáez Nieto JA, Rosel AB (April 2017). "First report of human infection by Christensenella minuta, a gram-negative, strickly anaerobic rod that inhabits the human intestine". Anaerobe. 44: 124–125. doi:10.1016/j.anaerobe.2017.03.007. PMID 28286022.
14. Zou Y, Xue W, Lin X, Hu T, Liu SW, Sun CH, et al. (2021-02-22). "Taxonomic Description and Genome Sequence of Christensenella intestinihominis sp. nov., a Novel Cholesterol-Lowering Bacterium Isolated From Human Gut". Frontiers in Microbiology. 12: 632361. doi:10.3389/fmicb.2021.632361. PMC 7937921. PMID 33692769.
15. Ndongo S, Dubourg G, Khelaifia S, Fournier PE, Raoult D (September 2016). "Christensenella timonensis, a new bacterial species isolated from the human gut". New Microbes and New Infections. 13: 32–33. doi:10.1016/j.nmni.2016.05.010. PMC 4925455. PMID 27408737. (This paper currently has an expression of concern, see doi:10.1016/j.nmni.2024.101277, PMID 38799867,  Retraction Watch. If this is an intentional citation to a such a paper, please replace {{expression of concern|...}} with {{expression of concern|...|intentional=yes}}.)

• Biology

• Clostridiaceae
• Gram-negative bacteria
• Bacteria described in 2011