WikiBiomeThe human microbiome encyclopediaRanked matches across titles, topics, categories, and article introductions, filtered to microbe.
A Gram-negative, aerobic, non-fermenting coccobacillus and a member of the ESKAPE group of priority pathogens (Enterococcus, Staphylococcus, Klebsiella, Acinetobacter, Pseudomonas, Enterobacter). Acinetobacter baumannii is among the most problematic nosocomial pathogens…
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 …
A pathotype of escherichia coli that adheres to and invades intestinal epithelial cells, survives and replicates within macrophages, and is strongly associated with ileal Crohn's disease. Unlike classical diarrheagenic E. coli pathotypes (EPEC, ETEC, EHEC), AIEC does no…
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…
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…
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 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…
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…
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.…
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…
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…
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 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…
Burkholderiales is an order of Gram-negative Betaproteobacteria that includes environmentally versatile genera such as Ralstonia, Burkholderia, and Sutterella. Many members are notable for their metal resistance mechanisms, which enable survival in heavy metal-contamina…
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…
The leading bacterial cause of diarrheal disease worldwide, with an estimated 400-500 million cases annually. C. jejuni is notable in the metallomics context for possessing a nickel-dependent [NiFe] hydrogenase essential for colonization but lacking urease -- a striking…
An opportunistic fungal pathogen whose relationship with metals is multifaceted: C. albicans can biosorb heavy metals from its environment, heavy metal exposure promotes its virulence in immunocompromised hosts, and metal nanoparticles are being developed as antifungal …
Candidozyma auris is the current name for NCBITaxon:498019. Liu and colleagues established the combination in 2024 as MycoBank MB 848169; Candida auris Satoh & Makimura 2009 is its basionym, not a separate species ncbi taxonomy candidozyma auris index fungorum candidozy…
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…
Chlamydia trachomatis is a Gram-negative, obligate intracellular bacterium and the most common bacterial sexually transmitted infection worldwide. Its biphasic developmental cycle — alternating between the infectious elementary body (EB) and the replicative reticulate b…
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…
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…
Clostridioides difficile is the current NCBI name for NCBITaxon:1496 and the correct, medically recommended combination recorded by LPSN. Both records retain Clostridium difficile as a validly published homotypic synonym of the same organism rather than a separate speci…
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…
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…
An encapsulated basidiomycete yeast that causes cryptococcal meningitis -- the leading cause of meningitis in HIV/AIDS patients and responsible for an estimated 180,000 deaths annually. Its nickel-dependent urease has been called the organism's "Achilles' heel" because …
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…
A Gram-positive obligate anaerobe and key estrobolome member that links metabolic dysbiosis to hormone-driven diseases, particularly endometriosis. E. lenta is remarkable for its ability to inactivate cardiac glycosides (like digoxin) and to produce beta-glucuronidase, …
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 family of Gram-negative, facultative anaerobic Gammaproteobacteria that includes many of the most important human pathogens: escherichia coli, klebsiella pneumoniae, salmonella typhimurium, shigella flexneri, yersinia pestis, proteus mirabilis, Morganella, and Serrati…
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…
A Gram-negative bacterium that spans the commensal-pathogen spectrum, with pathogenic variants (UPEC, STEC, EHEC) deploying nickel-dependent enzymes as virulence factors. E. coli is the model organism for nickel transport biology -- the NikABCDE system was first charact…
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, …
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 Gram-negative obligate anaerobe that occupies a paradoxical niche in the gut microbiota: as a weak butyrate producer (short-chain fatty acid), it has anti-inflammatory potential; as a virulent invasive pathobiont in inflammatory bowel disease (particularly ulcerative …
Gardnerella vaginalis is a Gram-variable, facultatively anaerobic bacterium that is the key organism in bacterial vaginosis (BV), the most common vaginal infection in women of reproductive age. Its sialidase production, biofilm-forming capacity, and associations with he…
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…
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…
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…
A Gram-negative opportunistic pathogen and member of the ESKAPE group of antibiotic-resistant priority pathogens. K. pneumoniae deploys multiple nickel-dependent enzymes for virulence and relies on the dual-function metallophore yersiniabactin for both iron and nickel s…
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…
A Gram-positive, facultatively anaerobic bacterium that is the dominant species in the healthy human vaginal microbiome and a defining member of Community State Type I (CST-I). L. crispatus dominance is associated with reproductive health, pathogen resistance, and reduc…
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…
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…
The causative agent of tuberculosis (TB), the leading infectious disease killer worldwide (~1.3 million deaths annually). M. tuberculosis has an exceptionally complex metal biology: it deploys nickel-dependent hydrogenase and urease for intracellular survival, species-s…
Nakaseomyces glabratus is the current name for NCBITaxon:5478. Takashima and Sugita established the current combination in 2022 as MycoBank MB 843854; Candida glabrata is a homotypic synonym and former combination, while Cryptococcus glabratus H.W. Anderson 1917 is the …
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…
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…
Penicillium is a genus of filamentous fungi best known as the source of penicillin. In the WikiBiome context, Penicillium appears in the gut mycobiome — the fungal component of the microbiome — with associations across ASD, pancreatitis, and cardiometabolic disease.
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 obligate anaerobe that occupies a unique context-dependent niche in the human gut microbiome. P. copri is significantly enriched in rheumatoid arthritis patients and is associated with metabolic syndrome and obesity, yet in other contexts it can function…
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…
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…
A Gram-negative uropathogen whose Ni-dependent urease is the central driver of catheter-associated urinary tract infection (CAUTI) pathogenesis. Urease-mediated urea hydrolysis produces ammonia and alkalinizes urine, triggering precipitation of struvite (magnesium ammon…
An opportunistic Gram-negative pathogen with a unique dual-use siderophore system: its pyoverdine and pyochelin serve not only as iron scavengers but as extracellular chelators of toxic metals including nickel, copper, and cadmium. This makes P. aeruginosa unusually wel…
Ralstonia is a genus of Gram-negative, aerobic bacteria in the class Betaproteobacteria. While Wikipedia focuses on R. solanacearum (a plant pathogen), the WikiBiome-relevant species are R. pickettii and R. metallidurans (now Cupriavidus metallidurans) — organisms with …
Ruminococcus albus is a Gram-positive, obligate anaerobic bacterium that represents one of the primary cellulolytic (fiber-degrading) specialists in the human gut microbiota. This species constructs cellulosomes — extraordinary multi-enzyme complexes organized on bacter…
A Gram-positive obligate anaerobe that has emerged as a pro-inflammatory pathobiont enriched across multiple disease states including crohns disease, depression, and multiple sclerosis. R. gnavus produces a species-specific inflammatory polysaccharide that activates int…
Saccharomyces cerevisiae is a unicellular budding fungus (ascomycete) ubiquitous in fermentation, brewing, bread-making, and increasingly used as a pharmaceutical probiotic (Hatoum et al. 2012). The strain S. boulardii (also called S. cerevisiae var. boulardii) is the m…
Salmonella is a genus of Gram-negative, facultatively anaerobic bacteria in the family Enterobacteriaceae. The two species — S. enterica (with 2,500 serovars including Typhimurium and Typhi) and S. bongori — cause a spectrum of disease from self-limiting gastroenteritis…
A Gram-negative enteric pathogen that possesses four distinct hydrogenases of the [NiFe] class -- the most of any well-characterized human pathogen. These hydrogenases are critical for intracellular survival within macrophages, and a triple hydrogenase mutant is 100% av…
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…
Serratia marcescens is a Gram-negative, facultatively anaerobic member of the Enterobacteriaceae, historically recognized by its distinctive red pigment prodigiosin. Once considered a harmless environmental saprophyte, S. marcescens is now recognized as a significant op…
Shigella is a genus of Gram-negative, facultatively anaerobic bacteria in the family Enterobacteriaceae, closely related to Escherichia coli — so closely that many 16S rRNA-based studies report them as the Escherichia/Shigella complex, unable to distinguish the two gene…