WikiBiomeThe human microbiome encyclopediaRanked matches across titles, topics, categories, and article introductions.
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 …
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…
Antimicrobial metals are metal ions and metal-based materials that kill or inhibit microorganisms. Copper, silver, zinc, and gallium are the principal agents, each exploiting different aspects of microbial metal biology. What makes this field particularly relevant to Wi…
The ability of microorganisms to survive and replicate in the presence of antimicrobial agents — antibiotics, antifungals, antivirals, antiparasitic drugs — at concentrations that would normally inhibit or kill them. Antimicrobial resistance (AMR) is designated by the W…
Autophagy (from Greek, "self-eating") is the cellular process of degrading and recycling damaged organelles, misfolded proteins, and intracellular pathogens through lysosomal digestion. It is the cell's primary quality control mechanism -- a housekeeping system that bec…
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…
Beta-glucuronidase (β-glucuronidase, EC 3.2.1.31) is an enzyme that catalyzes the hydrolysis of glucuronidated compounds, cleaving the β-1,4-glycosidic bond between a sugar and a glucuronic acid group. In the microbiome, beta-glucuronidase is the key enzyme of the estro…
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 selective semipermeable border formed by brain endothelial cells connected by tight junctions, pericytes, and astrocytic end-feet. The BBB restricts passage of most molecules from blood to brain, protecting the CNS from toxins, pathogens, and inflammatory mediators. M…
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 heterodimer of S100A8 and S100A9 calcium-binding proteins that constitutes approximately 60% of the cytosolic protein content of neutrophils. Calprotectin is a central effector of nutritional immunity, sequestering essential transition metals from invading pathogens a…
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 …
Cardiovascular disease (CVD) -- encompassing atherosclerosis, coronary artery disease, hypertension, myocardial infarction, heart failure, and stroke -- is the leading cause of death globally. The gut-heart axis has emerged as a central paradigm linking microbial metabo…
Chitotriosidase (CHIT1) is a human chitinase that degrades chitin — the structural polysaccharide of fungal cell walls, insect exoskeletons, and parasitic helminths. It is the most abundant chitinase in human serum and represents a direct arm of innate nutritional immun…
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 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…
The collective ability of the resident gut microbiome to prevent colonization by exogenous pathogens and suppress expansion of resident pathobionts. Colonization resistance is not a property of any single organism but an emergent function of the whole microbial communit…
Colorectal cancer (CRC) is the third most common cancer worldwide and the second leading cause of cancer death. Over 90% of cases are sporadic, driven by a complex interplay between genetic predisposition, dietary habits, gut microbiome composition, and environmental ex…
An essential trace element with a striking dual nature: required for survival as a cofactor for critical enzymes (SOD1, cytochrome c oxidase, ceruloplasmin), yet toxic in excess through Fenton-like redox cycling and mis metallation of iron-sulfur clusters. Copper is ele…
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…
This page identifies the contradictions and clinical dilemmas that become visible only when the 236 source pages in this wiki are read together. Each paradox describes a situation where evidence-based dietary or supplementation advice -- advice that is correct for most …
Every meal delivers metals to the gut lumen — essential minerals, trace elements, and contaminants alike. These metals do not passively transit the GI tract. They actively reshape the microbial ecosystem, selecting for metal-tolerant organisms, enabling virulence in met…
Dimethylglyoxime (DMG) is a high-affinity, nickel-specific chelator — two DMG molecules coordinate one Ni²⁺ ion to form a characteristic red complex (Tschugaeff reaction). Unlike broad-spectrum chelation agents (EDTA, DMSA) that bind multiple divalent cations indiscrimi…
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…
Enterococcus faecalis is a Gram-positive, facultatively anaerobic coccus that inhabits the gastrointestinal tract, oral cavity, and genitourinary tract of humans. It is a commensal in the healthy gut at low abundance but is one of the most clinically significant opportu…
Enterococcus faecium is a Gram-positive, facultatively anaerobic bacterium that epitomizes the metal-antibiotic co selection problem in modern medicine. As one of the six ESKAPE pathogens (the group responsible for the majority of hospital-acquired infections that fail …
Functional shielding is the phenomenon in which one microorganism — typically a fungus — physically and immunologically protects a co-resident pathogen from host immune attack, antimicrobial agents, and oxidative stress. The shielding organism's biofilm matrix acts as a…
Alphabetical definitions of specialist terms used throughout this wiki. Where a full concept page exists, the term links to it. --- AhR (aryl hydrocarbon receptor) -- A ligand-activated transcription factor that senses microbial metabolites (especially indoles from tryp…
The third nickel-dependent enzyme class in human pathogens, after urease and hydrogenase. Glyoxalase I detoxifies methylglyoxal, a reactive and toxic byproduct of glycolysis. While less well-known than urease or hydrogenase as a virulence factor, GloI is emerging as a s…
[NiFe] hydrogenases are the second major nickel-dependent virulence factor class in human pathogens. Less widespread than urease but critical for energy metabolism in gastric, enteric, and intracellular pathogens. The discovery that H. pylori hydrogenase powers CagA tra…
Interferon gamma (IFN-γ) is the signature Th1 cytokine and the primary activator of macrophage antimicrobial functions. In the WikiBiome framework, IFN-γ is critical for two reasons: it drives nutritional immunity (iron restriction against intracellular pathogens) and i…
Innate immunity is the body's first-line, non-specific defense against pathogens — comprising physical barriers (epithelium, mucus), antimicrobial molecules (calprotectin, lactoferrin, defensins), pattern recognition receptors (TLRs, NOD-like receptors), and phagocytic …
The most abundant transition metal in the human body and arguably the most consequential metal in biology. Iron sits at the center of a paradox that drives pathology across virtually every disease domain: organisms need it for oxygen transport, energy metabolism, DNA sy…
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…
Lactobacillus jensenii defines Community State Type V (CST-V) in the vaginal microbiome. It produces hydrogen peroxide and lactic acid, contributing to vaginal defense against pathogens, though less dominant than lactobacillus crispatus (CST-I).
An iron-binding glycoprotein of the transferrin family that sequesters iron (and potentially other metals) from pathogens at mucosal surfaces and sites of inflammation. Lactoferrin is a key effector of nutritional immunity, complementing calprotectin's role in metal res…
Manganese is an essential trace element with a narrow therapeutic window: required as a cofactor for critical enzymes including Mn-SOD (SOD2), pyruvate carboxylase, arginase, and ribonucleotide reductase, yet profoundly neurotoxic at elevated levels martin 2022 manganes…
Transition metals serve as essential cofactors for pathogen virulence factors across virtually all domains of microbial life. The dependence of pathogens on metals they must scavenge from the host environment creates a fundamental tension at the heart of infectious dise…
This page synthesizes findings across 1,426 source pages to map the relationships between metals and disease. Where individual source pages document a single study's findings, this page identifies the patterns that emerge when those findings are laid side by side. ADVER…
Inflammation is a broad concept, but in the metallomics context it has a specific character: heavy metals and pathogens activate overlapping inflammatory pathways, creating convergent pathology where distinguishing the metal contribution from the microbial contribution …
Microbial metallomics is the study of how metals and microorganisms interact at the systems level — how metal availability shapes microbial communities, how microbes acquire and weaponize metals for virulence, and how this bidirectional metal-microbe interface drives di…
Microglia are the resident immune cells of the central nervous system, constituting 5-12% of all brain cells. They function as the brain's surveillance and defense system -- scanning for damage, clearing debris, pruning synapses during development, and mounting inflamma…
Nickel-glyoxalase (Ni-GlxI) is a bacterial variant of the glyoxalase I enzyme system that depends on nickel as its essential metal cofactor. This enzyme detoxifies methylglyoxal (MG), a toxic glycolysis byproduct that accumulates under glucose fermentation. Unlike the h…
Nickel-urease (urease, EC 3.5.1.5) is a metalloenzyme that catalyzes the hydrolysis of urea (NH₂-CO-NH₂) to ammonia (NH₃) and carbon dioxide (CO₂). The active site contains two nickel ions (Ni²⁺) coordinated by histidine and cysteine residues. Nickel-urease is expressed…
The strategy by which mammalian hosts withhold essential metals from invading pathogens to limit their growth. Well-established for iron and zinc; underexplored but potentially powerful for nickel.
The oral microbiome is the second most complex microbial community in the human body after the gut, harboring ~700 species across distinct niches (tongue, buccal mucosa, gingival crevice, saliva, dental plaque). While traditionally studied in the context of dental disea…
The second most common neurodegenerative disease, affecting over 10 million people worldwide dorsey 2018 parkinsons incidence meta analysis. Characterized by progressive loss of dopaminergic neurons in the substantia nigra, alpha-synuclein aggregation (Lewy bodies), and…
Pathogens deploy dedicated cellular machinery to import, store, regulate, and when necessary export transition metals. These systems complement the extracellular siderophores metallophores that scavenge metals from the host environment by providing the membrane transpor…
Hyperaccumulation is the ability of certain plant species to concentrate metals in their tissues at levels 10-100x higher than the surrounding soil. This is a genetically determined trait that evolved as a defense mechanism — metal-loaded tissues are toxic to herbivores…
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 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…
Reactive oxygen species — superoxide (O2•−), hydrogen peroxide (H2O2), and hydroxyl radical (OH•) — are chemically reactive molecules generated during normal metabolism and massively amplified by heavy metal exposure. ROS are both weapons (the host uses them to kill pat…
Sepsis is life-threatening organ dysfunction caused by a dysregulated host response to infection. In the WikiBiome framework, sepsis represents the catastrophic failure of both colonization resistance (pathogen invasion) and nutritional immunity (metal restriction). Inf…
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…
Siderophores are small, high-affinity iron-chelating molecules secreted by bacteria, fungi, and some plants to scavenge ferric iron (Fe3+) from their environment. In the context of infection, siderophores are the molecular weapons pathogens deploy to break through nutri…
Siderophores and metallophores are small-molecule chelators secreted by pathogens to scavenge metals from the metal-scarce host environment. They represent the extracellular arm of pathogen metal acquisition -- how pathogens reach out into the surrounding milieu to capt…
Small regulatory RNAs (sRNAs) are non-coding RNA molecules, typically 50-500 nucleotides long, that regulate gene expression post-transcriptionally in bacteria. In the context of metal biology and microbial pathogenesis, sRNAs serve as rapid-response coordinators that h…
A genus of Gram-positive, facultative anaerobic cocci that includes some of the most clinically significant human pathogens. Staphylococci are defined by their exceptionally comprehensive metal acquisition arsenal -- arguably the most thoroughly characterized of any bac…
Research summary -- not medical advice. This page synthesizes published research on why broad-spectrum antibiotics may worsen gut dysbiosis rather than correct it. This does NOT apply to life-threatening infections requiring antibiotic treatment. Consult a qualified hea…
A genus of Gram-positive facultative anaerobes that occupy niches ranging from benign commensals (dental plaque, skin) to acute pathogens (pharyngitis, impetigo, invasive disease). Streptococci are uniquely manganese-dependent for catalytic scavenging of reactive oxygen…
Streptococcus salivarius is a Gram-positive, facultatively anaerobic bacterium and one of the earliest colonizers of the human oral cavity. It dominates the tongue dorsum and saliva, representing up to 10% of the cultivable oral flora. S. salivarius occupies a paradoxic…
Iron deficiency is common and clinically significant across multiple conditions: postpartum anemia increases PPD risk 1.89-fold (RR = 1.887), low ferritin (<1 ug) increases PPD risk 3.98-fold azami 2019 anemia ppd meta analysis, iron deficiency impairs thyroid peroxidas…
Restricting dietary nickel has clear benefits for nickel-sensitive individuals: it resolves SNAS symptoms, improves Ni ACM, and even enhances H. pylori eradication. Campanale et al. (2014) found that adding a nickel-free diet to standard triple therapy increased H. pylo…
Transferrin is a glycoprotein (β₁-globulin, ~80 kDa) synthesized primarily by the liver that functions as the principal iron-transport protein in blood plasma. It binds ferric iron (Fe³⁺) with extraordinarily high affinity (Kd ~10⁻²³ M) and delivers it to cells via tran…
Trichoderma is a genus of filamentous ascomycete fungi ubiquitous in soil and plant root ecosystems. Best known as a biological control agent against plant pathogens, Trichoderma species produce an arsenal of hydrolytic enzymes and antimicrobial compounds. Rarely, they …
Type 2 diabetes (T2D) is a metabolic disease characterized by insulin resistance and progressive beta-cell dysfunction, affecting over 500 million people worldwide (IDF Diabetes Atlas 2021). The conventional framing centers on caloric excess and sedentary behavior. The …
A chronic inflammatory bowel disease characterized by continuous mucosal inflammation of the colon, extending proximally from the rectum. Unlike crohns disease, UC is limited to the colon, affects only the mucosa/submucosa (not transmural), produces no skip lesions, and…
The most widespread nickel-dependent virulence factor across human pathogens. Urease is found in at least 40 prokaryotic and 9 eukaryotic pathogenic species, making it the single most important enzyme linking dietary/environmental nickel to infectious disease.
Zinc is the most widely utilized transition metal cofactor in biology. Approximately 9-10% of the eukaryotic proteome and 5-6% of the bacterial proteome consists of zinc-binding proteins capdevila 2024 bacterial metallostasis sensing trafficking. An estimated one-third …