WikiBiomeThe human microbiome encyclopediaRanked matches across titles, topics, categories, and article introductions.
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…
WHO Priority 1: Critical. A Gram-negative, strictly aerobic coccobacillus and one of the most dangerous nosocomial pathogens on the planet. A. baumannii belongs to the ESKAPE group and causes ventilator-associated pneumonia, wound infections, and bloodstream infections …
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…
A genus of Gram-positive, facultatively anaerobic, filamentous bacteria that are among the most abundant colonizers of the human oral cavity. Actinomyces species, particularly A. naeslundii, play dual roles as early dental plaque colonizers and as opportunistic pathogen…
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…
Aerococcus is a genus of Gram-positive, alpha-hemolytic, catalase-negative cocci. The primary species of clinical relevance are A. urinae (a cause of urinary tract infections, particularly in elderly men) and A. christensenii (a vaginal commensal). In the WikiBiome vaul…
Aeromonas is a genus of Gram-negative, facultatively anaerobic bacteria found in aquatic environments and, increasingly recognized as an opportunistic gut pathogen. Several species — particularly Aeromonas hydrophila, A. veronii, and A. caviae — are associated with gast…
Agathobacter rectalis (Hauduroy et al. 1937) Rosero et al. 2016 is the selected current name for NCBITaxon:39491. NCBI Taxonomy lists Eubacterium rectale as a homotypic synonym, and LPSN identifies A. rectalis as the correct validly published combination ncbi taxonomy a…
Alishewanella is a genus of Gram-negative, facultative anaerobic bacteria within the class Gammaproteobacteria. Primarily known as environmental organisms, Alishewanella species have been identified in the microbiome of deep endometriosis — both in vaginal samples and w…
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…
Alloprevotella is a genus of Gram-negative, obligate anaerobic bacteria within the family Prevotellaceae that represents a distinct clade from prevotella with specific protective roles in type 2 diabetes prevention and metabolic health. Alloprevotella depletion is one o…
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…
Alternaria is a ubiquitous environmental mold genus comprising over 300 species, with A. alternata as the most common human-associated species. Primarily recognized as an outdoor allergen and plant pathogen, Alternaria is increasingly documented as a component of the hu…
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 …
A genus of Gram-positive obligate anaerobes in the family Lachnospiraceae (Clostridium cluster XIVa) that occupy a critical metabolic relay position in gut ecosystem stability: converting lactate to butyrate. Anaerostipes is one of the most consistently depleted genera …
Anaerotruncus is a Gram-positive obligate anaerobic genus within the Ruminococcaceae (Firmicutes). First isolated from human feces, it is a minor member of the healthy gut community that has attracted attention for its consistent enrichment in aging-related conditions a…
A ubiquitous filamentous fungal genus that is both an environmental saprophyte and an opportunistic human pathogen. A. fumigatus is the primary cause of invasive aspergillosis in immunocompromised patients, while A. niger is relevant to food contamination. The genus is …
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…
A Gram-positive, aerobic to facultatively anaerobic, spore-forming genus that bridges environmental and human microbiology. The genus encompasses both beneficial species (B. subtilis, B. coagulans as probiotics) and pathogens (B. cereus causing food poisoning, B. anthra…
Bacteroidaceae is a family of obligate anaerobic, Gram-negative bacteria in the order bacteroidales. The dominant genus is bacteroides, which includes B. fragilis, B. vulgatus, B. thetaiotaomicron, and B. uniformis. Bacteroidaceae are among the most abundant gut bacteri…
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…
A Gram-negative obligate anaerobe and the most clinically significant member of the Bacteroides genus. B. fragilis occupies a unique dual position in gut microbiology: as a non-toxigenic commensal (NTBF), it produces polysaccharide A (PSA) that shapes immune tolerance; …
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…
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…
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…
A genus of Gram-positive, obligate anaerobic bacteria that dominate the infant gut microbiome and remain important commensals throughout life. Bifidobacterium species are distinctive in the metallomics context because some species possess Ni-dependent urease -- an unusu…
A genus of Gram-positive, obligate anaerobic bacteria within the lachnospiraceae family that produces short chain fatty acids and plays a significant role in bile acid metabolism. Key species include B. obeum, B. wexlerae, B. hydrogenotrophica, and B. producta. While pr…
A genus of spirochete bacteria transmitted by Ixodes ticks, best known as the causative agent of Lyme disease -- the most common tick-borne illness in the Northern Hemisphere. Borrelia burgdorferi sensu lato comprises approximately 20 genospecies, with B. burgdorferi se…
A genus of Gram-negative intracellular pathogens causing brucellosis, the most common bacterial zoonosis worldwide. Brucella species depend on nickel-activated urease for gastrointestinal survival during the initial phase of infection, and urease immunization has been s…
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…
Campylobacter is a genus of Gram-negative, microaerophilic, spiral-shaped bacteria. C. jejuni is the most common bacterial cause of foodborne gastroenteritis worldwide and a trigger for post-infectious Guillain-Barré syndrome (molecular mimicry between Campylobacter LOS…
Caulobacter is a genus of Gram-negative obligate aerobic Alphaproteobacteria, with C. crescentus serving as one of the premier model organisms for studying bacterial cell biology. Found primarily in oligotrophic freshwater environments, Caulobacter is not a gut commensa…
Chlamydia is a genus of obligate intracellular, Gram-negative bacteria with a unique biphasic developmental cycle. The genus includes three species pathogenic to humans: chlamydia trachomatis (STI and trachoma), C. pneumoniae (respiratory infections, atherosclerosis ass…
Citrobacter is a genus of Gram-negative, facultatively anaerobic bacteria in the Enterobacteriaceae family, named for its ability to utilize citrate as a sole carbon source. Species include C. freundii, C. koseri, and C. rodentium (a mouse model for EHEC infection). In …
Cladosporium Link 1816 is the selected current genus name for NCBITaxon:5498 and is accepted as a genus by Species Fungorum ncbi taxonomy cladosporium species fungorum cladosporium. Davidiella Crous & U. Braun 2003 was introduced for the sexual morph of Cladosporium sen…
A large, polyphyletic genus of Gram-positive, obligate anaerobic, spore-forming bacteria encompassing both critical beneficial commensals and dangerous pathogens. Former Clostridium clusters IV and XIVa are now reclassified into ruminococcus-family Ruminococcaceae and l…
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…
Corynebacterium is a large genus of Gram-positive, club-shaped bacteria with over 130 species spanning commensals, opportunistic pathogens, and the classic pathogen C. diphtheriae. In the WikiBiome context, Corynebacterium is most notable for its dominance in the male r…
Debaryomyces is a genus of ascomycetous fungi, with D. hansenii being the most clinically relevant species, that represents a prominent opportunistic pathobiont enriched in inflammatory bowel disease, particularly crohns disease. Unlike many commensal fungi, Debaryomyce…
Deinococcus is a genus of extremophilic bacteria famous for extraordinary resistance to ionizing radiation, desiccation, and oxidative stress. D. radiodurans — "Conan the Bacterium" — can survive radiation doses 1,000 times greater than those lethal to humans. This resi…
A genus of Gram-negative, obligate anaerobic, sulfate-reducing bacteria (SRB) that produces hydrogen sulfide (H2S) as its primary metabolic end-product. H2S is a potent cytotoxin that disrupts colonocyte energy metabolism, damages the gut barrier, and promotes chronic i…
Dialister is a genus of Gram-negative, obligate anaerobic bacteria within the family Veillonellaceae that represents one of the strongest protective associations in gut-brain-axis research. Dialister depletion is a consistent and independent biomarker of depression, anx…
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…
Enterobacter is a genus of Gram-negative, facultatively anaerobic bacteria in the enterobacteriaceae family. Key species include enterobacter cloacae (the most clinically relevant) and E. hormaechei. Like other Enterobacteriaceae, Enterobacter possesses iron-dependent s…
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…
Escherichia is a genus of Gram-negative, facultatively anaerobic bacteria in the Enterobacteriaceae family. The primary species E. coli is simultaneously the most studied bacterium in biology and one of the most consistently enriched organisms in disease-associated micr…
Estrogen recirculation is the recycling loop by which conjugated estrogens excreted in bile are deconjugated by gut bacterial beta glucuronidase, reabsorbed across the intestinal epithelium, and returned to systemic circulation uzuner 2023 bidirectional relationship end…
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…
Finegoldia is a genus of Gram-positive, strictly anaerobic cocci, with Finegoldia magna as the primary species of clinical relevance. Formerly classified within Peptostreptococcus, this organism inhabits mucosal surfaces including the vaginal, skin, and gastrointestinal…
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, …
Fusicatenibacter is a Gram-positive obligate anaerobic genus within the Lachnospiraceae (Firmicutes). The primary species, F. saccharivorans, was isolated from human feces and is recognized as a beneficial commensal that produces butyrate and modulates intestinal immune…
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…
A Gram-negative, obligate anaerobic bacterium that has emerged as the most consistently CRC-associated microorganism in human gut microbiome studies. F. nucleatum is the primary species of concern, originally a commensal of the oral cavity that translocates to colorecta…
See also the genus page: gardnerella Gardnerella vaginalis is the primary causative agent of bacterial vaginosis (BV), the most common vaginal infection worldwide. This species page focuses on the species-level biology — particularly the vaginolysin cytotoxin and biofil…
Gemella is a genus of Gram-positive, facultatively anaerobic cocci that are normal commensals of the oral cavity. Species include G. morbillorum, G. haemolysans, and G. sanguinis. In the WikiBiome context, Gemella is notable for its oral-gut translocation pattern — an o…
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…
Haemophilus is a genus of small, Gram-negative, facultatively anaerobic coccobacilli that inhabit the upper respiratory tract, oral cavity, and gastrointestinal tract. The genus name literally means "blood-loving" -- a direct reference to its absolute requirement for he…
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…
Hungatella hathewayi is a Gram-positive, obligate anaerobic bacterium within the Firmicutes phylum (family Clostridiaceae) that has rapidly emerged as a multi-disease cancer-associated pathobiont. A recently reclassified genus (from Clostridium hathewayi), it is now rec…
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…
Klebsiella is a genus of Gram-negative, encapsulated, facultatively anaerobic bacteria in the Enterobacteriaceae family. With 141 file mentions across the vault, Klebsiella is one of the most frequently referenced opportunistic pathogens. The dominant species is klebsie…
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…
Lachnoclostridium is a genus of obligate anaerobic, Gram-positive bacteria in the lachnospiraceae family. It is a butyrate-producing commensal with emerging clinical significance as a treatment response biomarker and diagnostic marker.
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…
This page serves as the family-level hub for Lachnospiraceae, connecting the individual genus and species pages (roseburia, blautia, anaerostipes, agathobacter rectalis) with the overarching ecological and metabolic framework that defines the family. For the primary ent…
Lactobacillaceae is the family containing the genus lactobacillus and related genera. It is the dominant family in the healthy vaginal microbiome and a significant family in the gut. Family-level depletion is reported across schizophrenia szeligowski 2020 gut microbiome…
A genus of Gram-positive, facultatively anaerobic lactic acid bacteria (LAB) that are among the most extensively studied probiotics. In the metallomics context, Lactobacillus species are critical for two reasons: they actively detoxify heavy metals through binding and s…
A Gram-negative obligate anaerobe traditionally considered an oral commensal, but increasingly recognized as an opportunistic pathobiont with the ability to translocate from oral biofilms to the gastrointestinal tract and bloodstream. Leptotrichia species are prominentl…
A genus of lipophilic basidiomycete yeasts that is the dominant fungus on human skin and has recently been recognized as a significant component of the gut mycobiome. M. restricta, M. globosa, and M. furfur are the primary species. Originally studied as the cause of dan…
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…
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…
Mycoplasma is a genus of wall-less bacteria in the class Mollicutes, characterized by the smallest genomes of any self-replicating organisms (~580–1,350 kb). The lack of a cell wall makes them intrinsically resistant to beta-lactam antibiotics and undetectable by Gram s…