WikiBiomeThe human microbiome encyclopediaRanked matches across titles, topics, categories, and article introductions.
Small, high-affinity iron-chelating molecules secreted by bacteria and fungi to scavenge ferric iron (Fe3+) from the environment. Siderophore competition is a fundamental ecological force in the gut microbiome: organisms with superior iron acquisition systems gain a dec…
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…
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 …
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…
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 …
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 heavy metal traditionally considered safe enough for over-the-counter gastrointestinal remedies (Pepto-Bismol, De-Nol), bismuth is re-emerging as a potent antimicrobial synergist. Its key property: Bi3+ competes with Fe3+ for binding sites on siderophores and bacteria…
Cephalosporins are a class of beta-lactam antibiotics (five generations) that inhibit bacterial cell wall synthesis by binding penicillin-binding proteins. They are among the most prescribed antibiotic classes and among the most disruptive to the gut microbiome.
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 …
Competitive exclusion is the ecological principle that two species competing for the same limiting resource cannot coexist indefinitely — one will outcompete the other. In the gut microbiome, competitive exclusion is the primary mechanism by which commensal bacteria pre…
A chronic, relapsing-remitting inflammatory bowel disease (IBD) characterized by transmural inflammation of the gastrointestinal tract, most commonly affecting the terminal ileum and colon but capable of involving any segment from mouth to anus zhang 2017 intestinal mic…
Cystic fibrosis (CF) is an autosomal recessive disorder caused by mutations in the CFTR gene, producing defective chloride and bicarbonate transport across epithelial membranes. While the genetic defect affects multiple organ systems, chronic lung infection is the prima…
iron occupies a unique position among dietary metals: it is both an essential nutrient and a selective pressure that shapes the gut microbial ecosystem. The form, quantity, and bioavailability of dietary iron determines which microbes thrive and which are competitively …
Research summary — not medical advice. This page synthesizes published research on a mechanism-level intervention. It is not a clinical recommendation. Consult a qualified healthcare provider before making any changes to diet, supplementation, or treatment.
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…
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…
Research summary — not medical advice. This page synthesizes published research on a mechanism-level intervention. It is not a clinical recommendation. Consult a qualified healthcare provider before making any changes to diet, supplementation, or treatment.
A group 13 post-transition metal (atomic number 31) with no known biological function in any organism — yet one of the most promising antimicrobial metals precisely because of what it cannot do. Ga3+ is nearly identical to Fe3+ in ionic radius (0.62 Å vs 0.645 Å) and co…
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 gut-testis axis describes the bidirectional communication between the gut microbiome and the male reproductive system. Gut-derived microbial metabolites, immune signals, and systemic inflammatory mediators influence testicular function, testosterone biosynthesis, an…
Microbial communities do not acquire and use metals in isolation. Within biofilms, polymicrobial infections, and the gut microbiome, microbes engage in complex cooperative and competitive relationships mediated by metals -- sharing metallophores, concentrating metals in…
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…
Research summary — not medical advice. This page synthesizes published research on a mechanism-level intervention. It is not a clinical recommendation. Consult a qualified healthcare provider before making any changes to diet, supplementation, or treatment.
Lipocalin-2 (also known as NGAL — neutrophil gelatinase-associated lipocalin, or siderocalin) is a 25 kDa secreted protein produced by activated neutrophils, epithelial cells, and other innate immune cells. Its primary antimicrobial function is to sequester bacterial si…
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…
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…
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…
The outer membrane (OM) is the defining structural feature of Gram-negative bacteria, providing a permeability barrier that profoundly influences metal acquisition, antibiotic resistance, immune activation, and virulence. For the microbiome-metal axis, the outer membran…
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…
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…
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…
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…
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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…
Quorum sensing (QS) is cell-density-dependent communication in which bacteria produce, secrete, and detect small signaling molecules (autoinducers) to coordinate group behaviors — including biofilm formation, virulence factor production, siderophore synthesis, and antib…
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…
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…
Shotgun metagenomics is a sequencing approach that fragments and sequences all DNA in a sample -- bacterial, archaeal, fungal, viral, and host -- without prior amplification of a specific gene target. Unlike 16S rRNA amplicon sequencing, which identifies "who is there" …
Research summary -- not medical advice. This page synthesizes published research on why a commonly prescribed intervention may be counterproductive in this specific clinical context. Consult a qualified healthcare provider before making any changes to treatment.
Warning: Clinical Disclaimer: This STOP page represents a hypothesis based on mechanistic evidence and should NOT replace clinical judgment. Always consult with a qualified healthcare provider before modifying any treatment plan. Iron-deficiency anemia in colorectal can…
Warning: Clinical Disclaimer: This STOP page represents a hypothesis based on mechanistic evidence and should NOT replace clinical judgment. Always consult with a qualified healthcare provider before modifying any treatment plan. Evidence quality ratings reflect the str…
Harm potential: YELLOW — True iron deficiency anemia requires supplementation.
This knowledge-base record is being expanded from WikiBiome’s evidence graph.
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 …
Tuberculosis is caused by mycobacterium tuberculosis, an intracellular pathogen that survives inside macrophage phagosomes. In the WikiBiome framework, TB exemplifies the intracellular metal battleground: M. tuberculosis deploys mycobactins (lipophilic siderophores) and…
Virulence factors are the molecular tools that enable a microorganism to colonize, invade, evade immune defenses, and cause damage to the host. They include toxins, adhesins, invasins, immune evasion molecules, and metabolic enzymes that provide competitive advantages i…
The causative agent of plague -- one of the most devastating infectious diseases in human history and a modern bioterrorism concern (Tier 1 Select Agent). Y. pestis depends on nickel for glyoxalase I-mediated metabolic detoxification and produces the archetypal dual-fun…