Bacillota is a phylum of bacteria, most of which have gram-positive cell wall structure. 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.
The phylum Bacteroidota is composed of three large classes of Gram-negative, nonsporeforming, anaerobic or aerobic, and rod-shaped bacteria that are widely distributed in the environment, including in soil, sediments, and sea water, as well as in the guts and on the skin of animals.
Acidobacteriota is a phylum of Gram-negative bacteria. Its members are physiologically diverse and ubiquitous, especially in soils, but are under-represented in culture.
Faecalibacterium is a genus of bacteria. The genus contains several species including Faecalibacterium prausnitzii, Faecalibacterium butyricigenerans, Faecalibacterium longum, Faecalibacterium duncaniae, Faecalibacterium hattorii, and Faecalibacterium gallinarum. Its first known species, Faecalibacterium prausnitzii is gram-positive, mesophilic, rod-shaped, and anaerobic, and is one of the most abundant and important commensal bacteria of the human gut microbiota. It is non-spore forming and non-motile. These bacteria produce butyrate and other short-chain fatty acids through the fermentation of dietary fiber. The production of butyrate makes them an important member of the gut microbiota, fighting against inflammation.
Ruminococcus is a genus of bacteria in the class Clostridia. They are anaerobic, Gram-positive gut microbes. One or more species in this genus are found in significant numbers in the human gut microbiota. The type species is R. flavefaciens. As usual, bacteria taxonomy is in flux, with Clostridia being paraphyletic, and some erroneous members of Ruminococcus being reassigned to a new genus Blautia on the basis of 16S rRNA gene sequences.
Akkermansia is a genus in the phylum Verrucomicrobiota (Bacteria). The genus was first proposed by Derrien et al. (2004), with the type species Akkermansia muciniphila.
Alistipes is a Gram-negative genus of rod-shaped anaerobic bacteria in the phylum Bacteroidota. When members of this genus colonize the human gastrointestinal (GI) tract, they provide protective effects against colitis, and cirrhosis [citations needed]. However, this genus can also cause dysbiosis by contributing to anxiety, chronic fatigue syndrome, depression, and hypertension. Showcasing priority effects in microbiome assembly, when infant GI tracts have bacteria of the species Staphylococcus but not the species Faecalibacterium, Alistipes species become less capable of colonization. Alistipes, typically benign in the gut, can sometimes trigger infections like intra-abdominal abscesses and bloodstream infections, emphasizing the fine line between symbiosis and disease. This underscores the significance of comprehending their impact on human health within microbial ecosystems.
Parasutterella is a genus of Gram-negative, circular/rod-shaped, obligate anaerobic, non-spore forming bacteria from the Pseudomonadota phylum, Betaproteobacteria class and the family Sutterellaceae. Previously, this genus was considered "unculturable," meaning that it could not be characterized through conventional laboratory techniques, such as grow in culture due its unique requirements of anaerobic environment. The genus was initially discovered through 16S rRNA sequencing and bioinformatics analysis. By analyzing the sequence similarity, Parasutterella was determined to be related most closely to the genus Sutterella and previously classified in the family Alcaligenaceae.
Sutterella is a genus of Gram-negative, rod-shaped, non-spore-forming, Betaproteobacteria whose species have been isolated from the human gastrointestinal tract as well as canine feces. The genus of the family Sutterellaceae currently encompasses 4 distinct species, though at least 5 additional species have been proposed that do not yet meet International Code of Nomenclature of Prokaryotes (ICNP) standards for classification. Sutterella are frequently referred to as commensal in the context of human hosts, but are associated with inflammation, which has implications for a number of diseases.
Roseburia hominis is a bacterium first isolated from human feces. It is anaerobic, Gram-negative or Gram-variable, slightly curved rod-shaped and motile. The cells range in size from 0.5-1.5 to 5.0 μm. A2-183(T) is the type strain.
Peptoniphilus is a genus of bacteria in the phylum Bacillota (Bacteria).
Coprococcus is a genus of anaerobic cocci which are part of the human faecal microbiota. Despite the depletion of Coprococcus was found in colon cancer, there is no evidence for its protective role against colon cancer.
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.
Anaerostipes is a Gram positive and anaerobic bacterial genus from the family of Lachnospiraceae. Anaerostipes occurs in the human gut. Anaerostipes may protect against colon cancer in humans by producing butyric acid.
Anaerotruncus is a bacterial genus from the family of Oscillospiraceae, with one known species. Anaerotruncus bacteria occur in the human vaginal flora and gut.
Catenibacterium is a Gram-positive, non-spore-forming and anaerobic genus from the family Erysipelotrichidae, with one known species.
Anaerococcus is a genus of bacteria. Its type species is Anaerococcus prevotii. These bacteria are Gram-positive and strictly anaerobic. The genus Anaerococcus was proposed in 2001. Its genome was sequenced in August 2009. The genus Anaerococcus is one of six genera classified within the group GPAC. These six genera are found in the human body as part of the commensal human microbiota.
Anaeroglobus is a Gram-negative, cocci, non-spore-forming, anaerobic and non-motile genus of bacteria from the family of Veillonellaceae with one known species.
Mucispirillum is a genus in the phylum Deferribacterota (Bacteria). It is represented by the single species Mucispirillum schaedleri|. It has been found in the intestinal tract of some rodents and considered a commensal with some association to disease. This species has been found in cockroaches mice, turkeys, dogs, pigs, goats, termites, and sometimes humans. It is anaerobic and does not form spores. It is motile, flagellated and thought to have the ability to move through mucus.
Coprothermobacter is a genus of rod-shaped microorganisms, belonging to the bacterial family Coprothermobacteraceae of the phylum Coprothermobacterota. This taxonomic genus has been reclassified in 2018, after different phylogenetic studies showed that these bacteria represented a deeply branched taxon of the domain Bacteria; consequently, the clade including this genus has been classified in a separate phylum from Firmicutes, the phylum where it was included before reclassification.
