Bacillota

The renaming of phyla such as Firmicutes in 2021 remains controversial among microbiologists, many of whom continue to use the earlier names of long standing in the literature.{{cite news |last1=Robitzki |first1=Dan |date=4 January 2022 |title=Newly Renamed Prokaryote Phyla Cause Uproar |url=https://www.the-scientist.com/news-opinion/newly-renamed-prokaryote-phyla-cause-uproar-69578 |url-status=live |archive-url=https://web.archive.org/web/20220520094441/https://www.the-scientist.com/news-opinion/newly-renamed-prokaryote-phyla-cause-uproar-69578 |archive-date=20 May 2022 |access-date=23 May 2022 |work=The Scientist Magazine |language=en}} The name "Firmicutes" was derived from the Latin words for 'tough skin', referring to the thick cell wall typical of bacteria in this phylum. Scientists once classified the Firmicutes to include all Gram-positive bacteria, but have recently defined them to be of a core group of related forms called the low-G+C group, in contrast to the Actinomycetota.{{Citation needed|date=April 2025}}

The group is typically divided into the Clostridia, which are anaerobic, and the Bacilli, which are obligate or optional aerobes.{{cn|date=May 2024}} On phylogenetic trees, the first two groups show up as paraphyletic or polyphyletic, as do their main genera, Clostridium and Bacillus.{{cite journal |vauthors=Wolf M, Müller T, Dandekar T, Pollack JD |title=Phylogeny of Firmicutes with special reference to Mycoplasma (Mollicutes) as inferred from phosphoglycerate kinase amino acid sequence data |journal=Int. J. Syst. Evol. Microbiol. |volume=54 |issue=Pt 3 |pages=871–5 |date=May 2004 |pmid=15143038 |doi=10.1099/ijs.0.02868-0 |url=http://ijs.sgmjournals.org/cgi/pmidlookup?view=long&pmid=15143038 |archive-url=https://archive.today/20121209051705/http://ijs.sgmjournals.org/cgi/pmidlookup?view=long&pmid=15143038 |url-status=dead |archive-date=2012-12-09 |type=Comparative Study |citeseerx=10.1.1.126.3863 }} However, Bacillota as a whole is generally believed to be monophyletic, or paraphyletic with the exclusion of Mollicutes.{{cite journal | last = Ciccarelli | first = FD | year = 2006 | title = Toward automatic reconstruction of a highly resolved tree of life. | journal = Science | volume = 311 | issue = 5765 | pages = 1283–1287 | doi = 10.1126/science.1123061 | pmid = 16513982 | bibcode = 2006Sci...311.1283C | s2cid = 1615592 | url = http://www.sciencemag.org/cgi/content/full/311/5765/1283 | citeseerx = 10.1.1.381.9514 | access-date = 2020-12-02 | archive-date = 2010-07-24 | archive-url = https://web.archive.org/web/20100724140154/http://www.sciencemag.org/cgi/content/full/311/5765/1283 | url-status = live }}

The Bacillota are thought by some {{cite journal |author=Ruben E Valas, Philip E Bourne |date=2011 |title=The origin of a derived superkingdom: how a Gram-positive bacterium crossed the desert to become an archaeon |journal=Biology Direct |publisher=Biology Direct 2011; 6:16 |volume=6 |page=16 |doi=10.1186/1745-6150-6-16 |pmc=3056875 |pmid=21356104 |doi-access=free}} to be the source of the archaea, by models there the archaea branched relatively late from bacteria, rather than forming an independently originating early lineage (domain of life) from the last universal common ancestor of cellular life (LUCA).{{cn|date=May 2024}}

The currently accepted taxonomy based on the List of Prokaryotic names with Standing in Nomenclature (LPSN){{cite web|author=J. P. Euzéby |url=http://www.bacterio.cict.fr/classifphyla.html#Firmicutes |title=Firmicutes |access-date=2013-03-20 |publisher=List of Prokaryotic names with Standing in Nomenclature (LPSN) |url-status=dead |archive-url=https://web.archive.org/web/20130127030659/http://www.bacterio.cict.fr/classifphyla.html |archive-date=January 27, 2013}} and the National Center for Biotechnology Information (NCBI).{{cite web |author=Sayers |url=https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Tree&id=1239&lvl=3&lin |title=Firmicutes |access-date=24 April 2019 |publisher=National Center for Biotechnology Information (NCBI) taxonomy database |display-authors=etal |archive-date=28 July 2018 |archive-url=https://web.archive.org/web/20180728221348/https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Tree&id=1239&lvl=3&lin |url-status=live }}

More than 274 genera were considered {{As of|2016|lc=y}} to be within the Bacillota phylum,{{Citation needed|date=February 2019}} notable genera of Bacillota include:

Bacilli, order Bacillales

• Bacillus
• Listeria
• Staphylococcus

Bacilli, order Lactobacillales

• Enterococcus
• Lactobacillus
• Leuconostoc
• Streptococcus

Clostridia

• Clostridioides
• Clostridium
• Selenomonas

Erysipelotrichia

• Erysipelothrix

{{Anchor|Health implications}}

{{See also|Infectobesity}}

{{Fringe theories|date=March 2021|section}}

Bacillota can make up between 11% to 95% of the human gut microbiome.{{Cite journal |last1=Magne |first1=Fabien |last2=Gotteland |first2=Martin |last3=Gauthier |first3=Lea |last4=Zazueta |first4=Alejandra |last5=Pesoa |first5=Susana |last6=Navarrete |first6=Paola |last7=Balamurugan |first7=Ramadass |date=2020-05-19 |title=The Firmicutes/Bacteroidetes Ratio: A Relevant Marker of Gut Dysbiosis in Obese Patients? |journal=Nutrients |volume=12 |issue=5 |pages=1474 |doi=10.3390/nu12051474 |doi-access=free |issn=2072-6643 |pmc=7285218 |pmid=32438689}} The phylum Bacillota as part of the gut microbiota has been shown to be involved in energy resorption, and potentially related to the development of diabetes and obesity.{{cite journal |vauthors=Ley RE, Turnbaugh PJ, Klein S, Gordon JI |title=Microbial ecology: human gut microbes associated with obesity |journal=Nature |volume=444 |issue=7122 |pages=1022–1023 |year=2006 |pmid=17183309 |doi=10.1038/4441022a |type=Clinical Trial|bibcode=2006Natur.444.1022L |s2cid=205034045 }}{{cite news |last=Henig |first=Robin Marantz |url=https://www.nytimes.com/2006/08/13/magazine/13obesity.html?pagewanted=3&ei=5070&en=0c39c5880e4d7067&ex=1166850000 |title=Fat Factors |date=2006-08-13 |work=The New York Times Magazine |access-date=2008-09-28 |archive-date=2015-05-08 |archive-url=https://web.archive.org/web/20150508164124/http://www.nytimes.com/2006/08/13/magazine/13obesity.html?pagewanted=3&ei=5070&en=0c39c5880e4d7067&ex=1166850000 |url-status=live }}{{cite journal |vauthors=Ley RE, Bäckhed F, Turnbaugh P, Lozupone CA, Knight RD, Gordon JI |title=Obesity alters gut microbial ecology |journal=Proc. Natl. Acad. Sci. USA |volume=102 |issue=31 |pages=11070–11075 |date=August 2005 |pmid=16033867 |pmc=1176910 |doi=10.1073/pnas.0504978102 |type=Research Support|bibcode=2005PNAS..10211070L |doi-access=free }}Komaroff AL. The Microbiome and Risk for Obesity and Diabetes. JAMA. Published online December 22, 2016. doi:10.1001/jama.2016.20099 Within the gut of healthy human adults, the most abundant bacterium: Faecalibacterium prausnitzii (F. prausnitzii), which makes up 5% of the total gut microbiome, is a member of the Bacillota phylum. This species is directly associated with reduced low-grade inflammation in obesity.{{cite journal |last1=Chakraborti |first1=Chandra Kanti |title=New-found link between microbiota and obesity |journal=World Journal of Gastrointestinal Pathophysiology |date=15 November 2015 |volume=6 |issue=4 |pages=110–119 |doi=10.4291/wjgp.v6.i4.110 |pmid=26600968 |pmc=4644874 |doi-access=free }} F. prausnitzii has been found in higher levels within the guts of obese children than in non-obese children.

In multiple studies a higher abundance of Bacillota has been found in obese individuals than in lean controls. A higher level of Lactobacillus (of the Bacillota phylum) has been found in obese patients and in one study, obese patients put on weight loss diets showed a reduced amount of Bacillota within their guts.{{cite journal |last1=Million |first1=M. |last2=Lagier |first2=J.-C |last3=Yahav |first3=D. |last4=Paul |first4=M. |title=Gut bacterial microbiota and obesity |journal=Clinical Microbiology and Infection |date=April 2013 |volume=19 |issue=4 |pages=305–313 |doi=10.1111/1469-0691.12172 |pmid=23452229 |doi-access=free }}

Diet changes in mice have also been shown to promote changes in Bacillota abundance. A higher relative abundance of Bacillota was seen in mice fed a western diet (high fat/high sugar) than in mice fed a standard low fat/ high polysaccharide diet. The higher amount of Bacillota was also linked to more adiposity and body weight within mice.{{cite journal |last1=Turnbaugh |first1=Peter J. |title=Diet-Induced Obesity Is Linked to Marked but Reversible Alterations in the Mouse Distal Gut Microbiome |journal=Cell Host & Microbe |date=17 April 2008 |volume=3 |issue=4 |pages=213–223 |doi=10.1016/j.chom.2008.02.015 |pmid=18407065 |pmc=3687783 }} Specifically, within obese mice, the class Mollicutes (within the Bacillota phylum) was the most common. When the microbiota of obese mice with this higher Bacillota abundance was transplanted into the guts of germ-free mice, the germ-free mice gained a significant amount of fat as compared to those transplanted with the microbiota of lean mice with lower Bacillota abundance.{{cite journal |last1=Million |first1=M. |title=Gut bacterial microbiota and obesity |journal=Cell Microbiology and Infection |date=April 2013 |volume=19 |issue=4 |pages=305–313 |doi=10.1111/1469-0691.12172 |pmid=23452229 |doi-access=free }}

The presence of Christensenella (Bacillota, in class Clostridia), isolated from human faeces, has been found to correlate with lower body mass index.{{cite journal|last1=Goodrich|first1=Julia K.|last2=Waters|first2=Jillian L.|last3=Poole|first3=Angela C.|last4=Sutter|first4=Jessica L.|last5=Koren|first5=Omry|last6=Blekhman|first6=Ran|last7=Beaumont|first7=Michelle|last8=Van Treuren|first8=William|last9=Knight|first9=Rob|last10=Bell|first10=Jordana T.|last11=Spector|first11=Timothy D.|last12=Clark|first12=Andrew G.|last13=Ley|first13=Ruth E.|title=Human Genetics Shape the Gut Microbiome |journal=Cell|volume=159|issue=4|year=2014|pages=789–799|issn=0092-8674|doi=10.1016/j.cell.2014.09.053|pmid=25417156|pmc=4255478}}{{Open access}}

• List of bacteria genera
• List of bacterial orders

{{Reflist|2}}

• [https://web.archive.org/web/20130127030659/http://www.bacterio.cict.fr/classifphyla.html#Firmicutes Phylum "Firmicutes"] - J.P. Euzéby: List of Prokaryotic names with Standing in Nomenclature

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{{Bacteria classification}}

{{Gram-positive bacterial diseases}}

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Category:Bacteria phyla