WikiBiomeThe human microbiome encyclopediaRanked matches across titles, topics, categories, and article introductions, filtered to microbe.
A Gram-negative, obligate anaerobic genus within the family veillonellaceae (class Negativicutes, phylum Firmicutes) defined by its specialized amino acid fermentation -- the genus name literally means "acid from amino acids." Acidaminococcus ferments glutamate as its p…
Actinobacteria (reclassified as Actinomycetota in 2021) is a major Gram-positive, high-GC-content bacterial phylum with remarkable ecological breadth. In the gut, it typically comprises 1-10% of the community -- a distant third behind firmicutes and bacteroidetes -- but…
Adlercreutzia is a genus of Gram-positive, strictly anaerobic gut bacteria within the phylum Actinobacteria, named after Finnish researcher Herman Adlercreutz who pioneered phytoestrogen research. The genus is best known for producing equol, a potent bioactive metabolit…
A Gram-negative, obligate anaerobic genus within the Bacteroidetes phylum (family Rikenellaceae). Alistipes occupies a complex and context-dependent role in the gut ecosystem — some species carry well-documented anti-inflammatory properties, while the genus is paradoxic…
Alloscardovia is a genus of anaerobic, Gram-positive bacteria in the family Bifidobacteriaceae (phylum Actinobacteria). The primary species is A. omnicolens, which colonizes the human urogenital tract. In the WikiBiome vault, Alloscardovia appears exclusively in endomet…
Anaerococcus is a genus of Gram-positive, obligate anaerobic cocci within the phylum Firmicutes. It is a normal inhabitant of the human vaginal, skin, and gastrointestinal microbiota, but is recognized as an opportunistic pathogen in dysbiotic states, particularly when …
Atopobium is a genus of obligate anaerobic, Gram-positive bacteria in the phylum Actinobacteria. The primary species of clinical relevance is A. vaginae (recently reclassified as Fannyhessea vaginae), which is one of the hallmark organisms of bacterial vaginosis (BV) an…
Bacteroidales is an order of obligate anaerobic, Gram-negative bacteria within the phylum Bacteroidetes. It includes the families Bacteroidaceae (bacteroides), Prevotellaceae (prevotella), Rikenellaceae, and Porphyromonadaceae (porphyromonas). Bacteroidales are among th…
Bacteroides is the most abundant genus in the Western adult gut and a cornerstone of intestinal polysaccharide metabolism. As members of the bacteroidetes phylum, Bacteroides species encode enormous repertoires of carbohydrate-active enzymes (CAZymes) organized into pol…
Bacteroides caccae is a Gram-negative, obligate anaerobic member of the bacteroidetes phylum and a common fiber-degrading commensal in the human colon. While less individually prominent than bacteroides fragilis or bacteroides thetaiotaomicron, B. caccae has emerged as …
Bacteroides thetaiotaomicron is one of the most abundant and metabolically versatile commensals of the human gut, routinely cited as a model organism for studying host-microbe symbiosis. Its genome was one of the first human gut bacterial genomes fully sequenced, and su…
A Gram-negative, obligate anaerobic bacterium within the phylum Bacteroidetes and a common member of the healthy human gut microbiota. B. uniformis is a versatile polysaccharide degrader with emerging significance as an anti-inflammatory commensal whose depletion appear…
Bacteroidetes (recently reclassified as Bacteroidota) is one of the two dominant bacterial phyla in the human gut, together with firmicutes typically comprising 90% of the intestinal microbiota. Bacteroidetes are Gram-negative, obligately anaerobic, non-spore-forming ro…
Barnesiella is a validly published genus of Gram-negative, obligately anaerobic bacteria in the phylum Bacteroidota and family Barnesiellaceae. NCBI Taxonomy assigns the genus NCBITaxon:397864, and LPSN lists Barnesiella Sakamoto et al. 2007 as the correct name ncbi tax…
A class of Gram-negative bacteria within the phylum Proteobacteria that has emerged as a causal risk factor for schizophrenia and bipolar disorder through Mendelian randomization studies. Betaproteobacteria includes genera with notable metal tolerance -- particularly wi…
Bifidobacteriaceae is the family containing bifidobacterium and related genera (alloscardovia). It is the dominant family in the healthy infant gut and a significant commensal family in adults. Family-level depletion is documented in ASD (marked reduction of Actinobacte…
Bifidobacteriales is an order of Gram-positive, strictly anaerobic bacteria within the phylum Actinobacteria. The order contains the family Bifidobacteriaceae, which includes the genus Bifidobacterium — among the most widely studied probiotic organisms and a hallmark of…
Bifidobacterium adolescentis is a Gram-positive, obligate anaerobic species within the phylum Actinobacteria and the dominant Bifidobacterium species in the adult human gut. It is a specialist degrader of resistant starch and dietary fiber, producing acetate and lactate…
Bifidobacterium breve is a Gram-positive, obligate anaerobic species within the phylum Actinobacteria, predominantly found in the infant gut and breast milk. It is among the earliest colonizers of the neonatal intestine and plays a key role in human milk oligosaccharide…
A genus of Gram-positive, strictly anaerobic, butyrate-producing bacteria in the order Clostridiales (phylum Firmicutes). The type species, Butyricicoccus pullicaecorum, was originally isolated from chicken caecal content but has since been identified as a significant m…
A Gram-negative, obligate anaerobic genus within the Bacteroidetes phylum (family Odoribacteraceae). Despite its relatively recent characterization, Butyricimonas has gained significant attention as a member of the protective butyrate-producing consortium that is consis…
Butyrivibrio is a genus of Gram-positive, obligate anaerobic bacteria within the family Lachnospiraceae (phylum Firmicutes). Originally characterized as a dominant fiber-fermenting genus in the rumen, Butyrivibrio species are also found in the human colon where they con…
Christensenellaceae is a family of Gram-negative, strictly anaerobic bacteria within the order Clostridiales (phylum Firmicutes) that has emerged as one of the most consistently health-associated and heritable members of the human gut microbiome. First formally describe…
A class of Gram-positive, obligate anaerobic bacteria within the phylum Firmicutes that represents the most functionally diverse and clinically significant taxonomic class in the human gut microbiome. Clostridia encompasses the dominant butyrate producers sustaining col…
A genus of Gram-positive, obligate anaerobic bacteria within the Actinobacteria phylum (family Coriobacteriaceae) that has emerged as a consistent pathobiont enriched in cardiometabolic and autoimmune diseases. C. aerofaciens is the most studied species, with establishe…
A Gram-positive, obligate anaerobic genus within the lachnospiraceae family (Firmicutes phylum). Coprococcus is one of the most important butyrate-producing commensals in the human gut and has gained particular attention as the "happiness bug" -- one of very few taxa di…
A Gram-positive, obligate anaerobic genus within the lachnospiraceae family (Firmicutes phylum). Dorea occupies a mixed role in the gut ecosystem -- while it is a core member of the healthy human microbiome, several species are consistently enriched in autoimmune and ne…
Eggerthella is a genus of Gram-positive, strictly anaerobic, non-spore-forming bacteria in the family Eggerthellaceae (phylum Actinobacteria). The most studied species, Eggerthella lenta, was originally classified as Eubacterium lentum before reclassification. It is a n…
A genus of Gram-positive bacteria (primarily E. faecalis and E. faecium) that exemplifies the metal-antibiotic resistance co-selection crisis. Enterococci carry diverse metal tolerance genes for mercury, arsenic, copper, and cadmium on the same mobile genetic elements a…
Erysipelotrichaceae is a family within the phylum Firmicutes that has drawn increasing attention for its consistent enrichment in metabolic disorders. Members of this family are Gram-positive, obligate anaerobes found throughout the mammalian gastrointestinal tract, whe…
A genus of Gram-positive, obligate anaerobic bacteria within the Firmicutes phylum that includes several of the most important butyrate producers in the human colon. Key species are E. rectale, E. hallii (now reclassified as Anaerobutyricum hallii), and E. limosum. Cons…
Faecalibacterium is a genus of obligate anaerobic, Gram-positive bacteria in the family Ruminococcaceae (phylum Firmicutes). It is the most abundant genus in the healthy human colon (5–15% of fecal bacteria) and its depletion is the single most reproducible microbiome f…
Firmicutes (recently reclassified as Bacillota) is the dominant bacterial phylum in the Western adult gut, comprising the core community of short-chain fatty acid (SCFA) producers that maintain intestinal barrier integrity, regulate immune function, and influence system…
Flavobacterium is a genus of Gram-negative, aerobic bacteria within the phylum Bacteroidetes. Primarily environmental organisms found in soil and freshwater, Flavobacterium species have been identified in human microbiome studies of the cervical and reproductive tract, …
An order of Gram-negative, obligate anaerobic bacteria within the phylum Fusobacteriota (formerly Fusobacteria). This order-level page covers the broader taxonomic group that includes the well-characterized genus fusobacterium and its key species fusobacterium nucleatum…
Gordonibacter is a genus of Gram-positive, strictly anaerobic gut bacteria within the phylum Actinobacteria. It is recognized as a key participant in polyphenol metabolism, producing bioactive metabolites including equol (from dietary isoflavones) and urolithins (from e…
A genus of Gram-positive, strictly anaerobic bacteria in the family Erysipelotrichaceae (phylum Firmicutes) that is emerging as one of the most consistently protective gut commensals in human disease. Holdemanella is depleted across a striking range of conditions -- inf…
A Gram-positive, obligate anaerobic genus within the Firmicutes phylum (family Oscillospiraceae or Ruminococcaceae depending on classification) that possesses a unique metabolic capability: butyrate production from lysine fermentation rather than from dietary fiber. Thi…
Lachnobacterium is a genus of Gram-positive, obligate anaerobic bacteria within the family Lachnospiraceae (phylum Firmicutes). It is a commensal member of the healthy human gut microbiota, though relatively understudied compared to other Lachnospiraceae genera. Lachnob…
Lachnospira is a genus of Gram-positive, obligate anaerobic bacteria within the lachnospiraceae family (Firmicutes phylum). L. pectinoschiza, the type species, is a specialist pectin fermenter that produces short chain fatty acids from plant-derived polysaccharides. The…
A family within the Firmicutes phylum (order Clostridiales, formerly Clostridium cluster XIVa) that serves as a sentinel indicator of gut health -- its depletion is the single most consistent microbiome signature across nearly every disease represented in this wiki. The…
A Gram-positive, obligate anaerobic genus within the family lachnospiraceae (phylum Firmicutes) that was recently reclassified from Ruminococcus based on phylogenomic evidence. The key species Mediterraneibacter faecis (formerly Ruminococcus gnavus clade relatives) is a…
Megamonas is a genus of obligate anaerobic, Gram-negative bacteria in the family Veillonellaceae (class Negativicutes, phylum Firmicutes). The type species is Megamonas hypermegale, with M. funiformis also well-characterized. It is a common member of the human gut micro…
Megasphaera is a genus of obligate anaerobic, Gram-negative bacteria in the family Veillonellaceae (class Negativicutes, phylum Firmicutes). The genus occupies two distinct ecological niches — the vaginal microbiome (where it is a hallmark of bacterial vaginosis) and th…
Methylobacterium is a genus of methylotrophic alpha-Proteobacteria (phylum Pseudomonadota) predominantly found in soil, water, plant surfaces, and air environments. It is a methylotroph — capable of using one-carbon compounds such as methanol as a carbon and energy sour…
A class of bacteria within the phylum Tenericutes defined by the complete absence of a cell wall -- the smallest self-replicating organisms known, with minimal genomes (580 kb-1.4 Mb). While Mollicutes are best known through their pathogenic members (Mycoplasma pneumoni…
Mortierella is a genus of soil-dwelling fungi in the phylum Mortierellomycota (formerly placed in Zygomycota). While primarily known as environmental saprotrophs, Mortierella species have recently been identified as residents of the human gut mycobiome -- the fungal com…
Odoribacter splanchnicus is a Gram-negative, obligate anaerobic bacterium belonging to the family Odoribacteraceae within the phylum Bacteroidota (formerly Bacteroidetes). It is a commensal resident of the human colon recognized primarily as a producer of short chain fa…
Oscillibacter is a genus of Gram-negative, strictly anaerobic, motile bacteria within the family Oscillospiraceae (phylum Firmicutes). The type species, Oscillibacter valericigenes, was first isolated from the alimentary canal of a Japanese corbicula clam and named for …
An order of Gram-positive, obligate anaerobic bacteria within the class Clostridia (phylum Firmicutes) that has emerged as one of the most consistent markers of a healthy gut ecosystem. Oscillospirales members are butyrate producers associated with leanness and metaboli…
A Gram-negative, obligate anaerobic genus within the Bacteroidetes phylum, closely related to bacteroides fragilis. The best-characterized species, P. distasonis, has emerged as a key anti-inflammatory commensal with significant roles in bile acid metabolism and metabol…
A Gram-positive, obligate anaerobic bacterium within the Firmicutes phylum (family Peptostreptococcaceae) that has emerged as a consistently enriched organism in the colorectal cancer tumor microenvironment. While fusobacterium nucleatum receives the most attention as a…
A Gram-negative, obligate anaerobic genus within the Firmicutes phylum (family Acidaminococcaceae, class Negativicutes). The primary species P. faecium and the recently characterized P. succinatutens are specialized propionate producers that utilize succinate as their m…
A Gram-negative, obligate anaerobic genus within the phylum Bacteroidota (formerly Bacteroidetes) that was recently reclassified from Bacteroides based on phylogenomic evidence (Garcia-Lopez et al., 2019). The key species -- Phocaeicola vulgatus (formerly Bacteroides vu…
A Gram-negative, obligate anaerobic genus within the Bacteroidetes phylum that exemplifies context-dependent microbiome effects -- beneficial in some settings, pathogenic in others. P. copri is the dominant species in the human gut and a hallmark of plant-rich, fiber-ri…
A family of Gram-negative, obligate anaerobic bacteria within the phylum Bacteroidota (formerly Bacteroidetes) that includes the genus prevotella and the recently described alloprevotella. Prevotellaceae are specialist fiber fermenters producing short-chain fatty acids,…
Proteobacteria (recently reclassified as Pseudomonadota) is the phylum that signals trouble. In a healthy adult gut, Proteobacteria comprise less than 1% of the community. When they bloom to 10-50% of the microbiome, it marks a fundamental ecological shift -- the collap…
Rikenella is a genus of obligate anaerobic, Gram-negative bacteria in the family Rikenellaceae (phylum Bacteroidetes). The primary species is R. microfusus. In the WikiBiome vault, Rikenella is consistently depleted across disease states — a protective commensal whose l…
Rothia is a genus of Gram-positive, facultatively anaerobic bacteria in the family Micrococcaceae (phylum Actinobacteria). The most commonly identified species in microbiome studies are Rothia dentocariosa and Rothia mucilaginosa, both of which are primary inhabitants o…
Ruminococcaceae is a family of obligate anaerobic, Gram-positive bacteria in the order Clostridiales (phylum Firmicutes) that represents one of the most important butyrate-producing and fiber-degrading families in the human gut. Key genera include faecalibacterium (incl…
A genus of Gram-positive, obligate anaerobic cocci within the Firmicutes phylum that exemplifies dual-nature microbiology — containing both keystone beneficial species and disease-associated pathobionts within the same genus. The genus spans multiple former taxonomic gr…
A Gram-positive, obligate anaerobic genus within the phylum Actinobacteria (family Coriobacteriaceae) that has emerged as one of the most frequently identified taxa in Mendelian randomization studies across disparate conditions -- erectile dysfunction, chronic kidney di…
Sneathia is a genus of obligate anaerobic, Gram-negative bacteria in the phylum Fusobacteriota (formerly Fusobacteria). The primary species is S. sanguinegens (formerly Leptotrichia sanguinegens), with S. amnii also clinically significant. Sneathia is a member of the BV…
A Gram-negative, microaerophilic genus within the Proteobacteria phylum (family Sutterellaceae). The primary species S. wadsworthensis is classified as a pathobiont due to its IgA-degrading capacity and associations with neurodevelopmental and inflammatory conditions. H…
A Gram-positive, facultatively anaerobic genus within the class Erysipelotrichia (phylum Firmicutes) that has become one of the most frequently identified taxa in gut-brain and gut-immune Mendelian randomization studies. Turicibacter sanguinis, the type species, possess…
Tyzzerella is a genus of Gram-positive, strictly anaerobic bacteria within the family Lachnospiraceae (order Clostridiales, phylum Firmicutes). It was recently reclassified from Clostridium cluster XIVa and remains poorly characterized at the species level. The genus in…
A Gram-negative, obligate anaerobic genus within the Firmicutes phylum (class Negativicutes, family Veillonellaceae). The primary species V. parvula is a specialized lactate utilizer that occupies a unique metabolic niche by cross-feeding with lactate-producing bacteria…
A family of Gram-negative, obligate anaerobic bacteria within the Firmicutes phylum (class Negativicutes) that occupies a unique metabolic niche as specialized lactate utilizers. Veillonellaceae cannot ferment sugars directly -- instead, they cross-feed on lactate produ…
Verrucomicrobia is a bacterial phylum represented in the human gut almost exclusively by a single genus — Akkermansia — which comprises 1–5% of the healthy gut microbiota. Despite being a low-diversity phylum, Verrucomicrobia's importance is outsized: A. muciniphila is …