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…
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…
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…
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…
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…
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; …
A Gram-negative obligate anaerobe that exemplifies the commensal-pathobiont spectrum. B. vulgatus is a common component of the healthy gut microbiota, yet is significantly enriched in colorectal cancer and depression, suggesting a context-dependent pathogenic potential.…
Bilophila wadsworthia is a Gram-negative, obligate anaerobic, sulfite-reducing bacterium that has emerged as a key pathobiont linking high-fat diets, taurine metabolism, hydrogen sulfide production, and inflammatory disease. Its unique metabolic niche -- using taurine-c…
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…
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 …
Clostridium symbiosum is a Gram-positive, obligately anaerobic bacterium within the Clostridium cluster XIVa — a taxonomic group enriched for short-chain fatty acid (SCFA) producers and specialized bile acid metabolizers. Despite its ambiguous name (suggesting symbiotic…
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 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…
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…
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…
A Gram-negative obligate anaerobe that has emerged as a major pathogen in colorectal cancer (CRC) and inflammatory bowel disease. F. nucleatum is significantly enriched in CRC tissue and tumors compared to healthy mucosa, making it one of the strongest microbe-cancer as…
A gastric pathogen that is arguably the most nickel-dependent human pathogen known. Two of its key virulence factors — urease and [NiFe] hydrogenase — require nickel, and the bacterium has evolved an elaborate nickel trafficking, storage, and regulation system to suppor…
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…
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…
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…
Lactobacillus acidophilus is one of the most widely used probiotic species, with clinical trial evidence spanning multiple conditions. It is a component of many multi-strain probiotic formulations and has been tested in RCTs for schizophrenia, breast cancer chemotherapy…
Lactobacillus gasseri is a vaginal and gut commensal that defines Community State Type II (CST-II) in the vaginal microbiome. It is a common probiotic species with anti-obesity properties in clinical trials.
Lactobacillus iners is a Gram-positive, facultatively anaerobic bacterium that dominates the vaginal microbiome of many women worldwide, defining Community State Type III (CST-III) in vaginal microbiome classification. For decades, all vaginal Lactobacillus species were…
Lactococcus lactis is a Gram-positive, facultatively anaerobic, lactic acid bacterium best known as the workhorse of the dairy fermentation industry. It holds GRAS (Generally Recognized As Safe) status and has emerged as a versatile platform for probiotic and therapeuti…
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…
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 tract of a Japanese freshwater fish and named for…
A family of Gram-positive obligate anaerobes (formerly classified as the genus Oscillospira, now reclassified into Oscillibacter and related genera within Oscillospiraceae) that serve as keystone butyrate producers in the healthy human distal colonic microbiota (Konikof…
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…
Parvimonas micra is a small (0.5–1.0 µm), Gram-positive, obligately anaerobic coccus originally isolated from the human oral cavity that has emerged as one of the most consistent and universally enriched pathobionts in colorectal cancer across all geographic regions, ag…
A Gram-positive, obligate anaerobic genus that has emerged as one of the most consistently enriched taxa in colorectal cancer. The key pathogenic species P. anaerobius promotes colorectal carcinogenesis through multiple mechanisms including cholesterol biosynthesis indu…
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…
Peptostreptococcus stomatis is a Gram-positive, obligately anaerobic coccus originally isolated from the human oral cavity (oral streptococcal species) that has emerged as a carcinogenic oral pathobiont enriched in colorectal cancer, particularly in advanced stages. Unl…
A Gram-negative, obligate anaerobic genus with the keystone pathogen P. gingivalis at its center. Named for its porphyrin (heme) requirement, Porphyromonas is the prototypical periodontal pathogen and one of the most important organisms connecting oral health to systemi…
A Gram-negative obligate anaerobe and keystone pathogen of the oral microbiome that causes chronic periodontitis and is increasingly implicated in systemic diseases including alzheimers disease and cardiovascular disease. P. gingivalis virulence is fundamentally depende…
A Gram-negative, obligately anaerobic, black-pigmented bacterium and one of the classical periodontopathogens. P. intermedia belongs to the "orange complex" of periodontal pathogens (Socransky classification) and is distinguished by its iron and heme dependency -- the c…
Propionibacterium (largely reclassified as Cutibacterium for skin species) is a genus of Gram-positive, anaerobic to aerotolerant bacteria that produce propionic acid as their primary fermentation product. P. acnes (now Cutibacterium acnes) is the dominant skin commensa…
A genus of ascomycete yeasts that includes both a proven therapeutic probiotic (S. boulardii) and species associated with disease states (S. cerevisiae enriched in CRC mycobiome). This dual nature -- commensal/probiotic versus disease-associated -- parallels the bacteri…
A genus of Gram-negative, crescent-shaped, strictly anaerobic bacteria found in both the oral cavity and the gastrointestinal tract. Selenomonas species are characterized by their distinctive morphology -- a curved rod with a tuft of flagella arising from the concave si…
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…
A Gram-positive, facultatively anaerobic bacterium formerly classified as Streptococcus bovis biotype I that holds a unique position in clinical medicine as a sentinel organism for colorectal cancer. The detection of S. gallolyticus in blood cultures (bacteremia or endo…
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…