''Christensenella'' is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial n ...

of non-

spore In biology, a spore is a unit of sexual or asexual reproduction that may be adapted for dispersal and for survival, often for extended periods of time, in unfavourable conditions. Spores form part of the life cycles of many plants, algae, ...

-forming,

anaerobic Anaerobic means "living, active, occurring, or existing in the absence of free oxygen", as opposed to aerobic which means "living, active, or occurring only in the presence of oxygen." Anaerobic may also refer to: *Adhesive#Anaerobic, Anaerobic ad ...

, and nonmotile

bacteria Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were am ...

from the family Christensenellaceae. 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 Feces ( or faeces), known colloquially and in slang as poo and poop, are the solid or semi-solid remains of food that was not digested in the small intestine, and has been broken down by bacteria in the large intestine. Feces contain a rela ...

. ''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 Body mass index (BMI) is a value derived from the mass (weight) and height of a person. The BMI is defined as the body mass divided by the square of the body height, and is expressed in units of kg/m2, resulting from mass in kilograms and he ...

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. Alonso, B. L., Irigoyen von Sierakowski, A., Sáez Nieto, J. A., & Rosel, A. B. (2017). First report of human infection by ''Christensenella minuta'', a gram-negative, strickly [sic] anaerobic rod that inhabits the human intestine. Anaerobe, 44, 124–125. https://doi.org/10.1016/j.anaerobe.2017.03.007

References

Clostridiaceae Gram-negative bacteria Bacteria described in 2011 {{Clostridia-stub