MetaXplore Markers

GABA (gamma-aminobutyric acid), a neurotransmitter, is proposed to play a role in gut motility and gut-brain communication. While mostly produced in the brain, the role of microbial GABA consumption is unclear.

GABA (gamma-aminobutyric acid), a neurotransmitter, is proposed to play a role in gut motility and gut-brain communication. While mostly produced in the brain, the role of microbially produced GABA is unclear.

The enzyme urease breaks down urea into ammonia. The role of microbial urease remains unclear.

Lactate, produced by microbial fermentation of carbohydrates, can be converted to propionate or butyrate.

Vitamin K, a fat-soluble vitamin essential for blood clotting, is sourced from the diet or the microbiome.

Histamine, produced by immune cells and some microbes, may modulate immune function and gut motility.

Most faecal DNA is microbial. Human DNA sources include mucus, epithelial cells, blood, or contamination during sampling. High levels may be associated with ulcerative colitis, colorectal cancer, or C. difficile infection.

Oral species are species commonly found in the mouth. High levels may be associated with intestinal inflammation, PPI use or reduced bacterial load.

Beta-glucuronidases are enzymes that can re-activate some drugs and hormones. High levels may affect drug response and toxicity.

Branched chain amino acids (BCAAs) are supplied by diet and produced by gut microbes. High blood levels may be associated with systemic inflammation.

The B. fragilis toxin (fragilysin) gene is present in enterotoxigenic B. fragilis. High B. fragilis toxin levels may be associated with impaired intestinal barrier integrity.

Hexa-acylated lipopolysaccharides (hexa-LPS) are cell wall components in Gammaproteobacteria. High hexa-LPS may be associated with intestinal and systemic inflammation and impaired intestinal barrier integrity.

Propionate, a short-chain fatty acid produced from fibre fermentation, regulates the immune system. High propionate producing microbes may be associated with slow gut transit.

Butyrate, a short chain fatty acid produced from fibre fermentation, is the primary energy source for colon cells. Low levels may be associated with intestinal and systemic inflammation and impaired intestinal barrier integrity.

Acetate, the most abundant short-chain fatty acid, can be converted to butyrate. Low levels may be associated with intestinal inflammation.

Methane is an odourless gas produced by Archaeal species, also known as methanogens. High levels may be associated with reduced intestinal motility.

Hydrogen sulphide is a malodorous gas produced by some gut microbes from sulphur-containing compounds. Optimal levels may be associated with intestinal barrier integrity.

Trimethylamine is a disease-associated metabolite produced by from carnitine or choline and is converted to trimethylamine-n-oxide (TMAO) in the liver. High plasma TMAO may be associated with systemic inflammation.

3-indolepropionic acid (IPA) is a beneficial metabolite produced from tryptophan. Low IPA may be associated with intestinal and systemic inflammation and impaired intestinal barrier integrity.

Oxalate is a key component in kidney stones. Low oxalate consuming microbes may be associated with increased urinary oxalate excretion.

Mucin is the primary component of mucus that protects the gut barrier. High levels of mucin degrading microbes may be associated with intestinal inflammation.

A measure of species count and evenness. Low microbial diversity may be associated with microbiome instability, systemic inflammation and faster gut transit time.

Discrepant test results cannot be resolved as positive or negative. If clinically indicated, repeat sample collection and further testing are recommended.

Yersinia enterocolitica s a foodborne pathogen that can cause invasive gastroenteritis often associated with bloody diarrhoea. Most cases are self-limiting, with treatment typically needed for immunocompromised or severely symptomatic patients however, consideration of the patient's clinical presentation is recommended. Colonization with non-toxigenic strains is possible. Positive faecal occult blood or suspected hemorrhagic colitis warrants urgent investigation and specialist consultation.

Vibrio species (V. cholerae, V. parahaemolyticus, V. vulnificus) typically cause watery diarrhoea, fever, and occasionally bloody diarrhoea. Colonisation with non-toxigenic strains is possible. Most cases are self-limiting, with treatment usually only needed for immunocompromised or severely symptomatic patients. Consideration of the patient's clinical presentation is recommended. Positive faecal occult blood or suspected haemorrhagic colitis warrants urgent investigation and specialist consultation.

Salmonella spp. are foodborne pathogens that can cause gastroenteritis and sometimes bloody diarrhoea. Most cases are self-limiting, with treatment usually needed only for immunocompromised or severely symptomatic patients. Consideration of the patient's clinical presentation is recommended. Positive faecal occult blood or suspected haemorrhagic colitis warrants urgent investigation and specialist consultation.

Escherichia coli, a natural coloniser of the gut, includes harmless strains and foodborne pathogens. Enteropathogenic E. coli (EPEC) is a major cause of infantile diarrhoea in developing countries. Medical treatment is recommended for symptomatic patients.

Escherichia coli, a natural coloniser of the gut, includes both harmless strains and foodborne pathogens. Shigella spp./ enteroinvasive E. coli (EIEC) can cause diarrhoea with fever, and sometimes bloody diarrhoea. Medical treatment is advised for symptomatic patients. Positive faecal occult blood or suspected haemorrhagic colitis warrants urgent investigation and specialist consultation.

Escherichia coli, a natural coloniser of the gut, includes both harmless strains and foodborne pathogens. Shiga toxin-producing E. coli (STEC) can cause acute diarrhoea, hemorrhagic colitis, and hemolytic uremic syndrome (HUS). Medical treatment is advised for symptomatic patients. Positive faecal occult blood or suspected haemorrhagic colitis or HUS warrants urgent investigation and specialist consultation.

Escherichia coli, a natural coloniser of the gut, includes both harmless strains and foodborne pathogens. E. coli O157 can cause acute diarrhoea, haemorrhagic colitis, and haemolytic uremic syndrome (HUS). Medical treatment is advised for symptomatic patients. Positive faecal occult blood or suspected haemorrhagic colitis or HUS warrants urgent investigation and specialist consultation.

Escherichia coli, a natural coloniser of the gut, includes both harmless strains and foodborne pathogens. Enteroaggregative E. coli (EAEC) can cause traveller’s or persistent diarrhoea. Traveller’s diarrhoea is typically self-limiting, with rehydration as the main treatment. Anti-diarrhoeal drugs may help but should not be used in children. Antibiotics are effective for moderate to severe cases.

Escherichia coli, a natural coloniser of the gut, includes both harmless strains and foodborne pathogens. Enterotoxigenic E. coli (ETEC) causes traveller’s diarrhoea and cholera-like illness in areas with poor sanitation. Traveller’s diarrhoea is usually self-limiting, with rehydration as the primary treatment. Anti-diarrhoeal drugs may help but should not be used in children. Antibiotics are effective for moderate to severe cases.

C. difficile is a leading cause of healthcare-associated infections, with hypervirulent strains producing elevated levels of toxins A and B, which drive its pathogenicity. Risk factors include antibiotic or proton pump inhibitor use, advanced age, immunosuppression, and inflammatory bowel disease (IBD). Infections can result in severe gastroenteritis, requiring treatment for symptomatic patients. Positive faecal occult blood or suspected haemorrhagic colitis requires urgent investigation and specialist consultation.

C. difficile is a major cause of healthcare-associated infections, with toxin B central to its pathogenicity. Risk factors include antibiotic or proton pump inhibitor use, advanced age, immunosuppression, and inflammatory bowel disease. Infections can cause severe gastroenteritis, requiring treatment for symptomatic patients. Positive faecal occult blood or suspected haemorrhagic colitis warrants urgent investigation and specialist consultation.

Campylobacter jejuni and C. coli are foodborne pathogens that can cause gastroenteritis. Most cases are self-limiting, with treatment typically needed only for immunocompromised or severely symptomatic patients, however, consideration of the patient's clinical presentation is recommended. Positive faecal occult blood or suspected haemorrhagic colitis warrants urgent investigation and specialist consultation.

Aeromonas spp. are food and waterborne pathogens that are common in fresh and brackish water. Clinical presentations include asymptomatic carriage and traveller’s diarrhoea. Most cases are self-limiting, with treatment typically needed only for immunocompromised patients those with severe or persistent symptoms. Consideration of the patient's clinical presentation is recommended.

Giardia lamblia is a waterborne parasite that can cause gastroenteritis. Clinical presentation ranges from asymptomatic carriage to acute or chronic gastrointestinal infections, with medical treatment recommended for symptomatic patients.

Entamoeba histolytica is a food and waterborne parasite that can cause amoebic dysentery. Clinical presentation ranges from asymptomatic carriage to invasive gastroenteritis. Medical treatment is advised even for asymptomatic cases to prevent disease spread. Positive faecal occult blood or suspected haemorrhagic colitis warrants urgent investigation and specialist consultation.

The pathogenic role of Dientamoeba fragilis has not been established. Antimicrobial treatment is usually unnecessary and may disrupt the gut microbiome without clearing the protozoa. For symptomatic cases, other causes (e.g., infections, IBS, food intolerances) should be excluded. Screening for organism clearance or testing family members is not recommended.

Cyclospora cayetanensis is a waterborne parasite that can cause gastroenteritis. Most cases are self-limiting, with treatment typically needed only for immunocompromised patients and those with severe or persistent symptoms. Consideration of the patient's clinical presentation is recommended.

Some species of the waterborne parasite Cryptosporidium can cause cryptosporidiosis in humans, primarily C. hominis and C. parvum. It is usually self-limiting. Treatment is generally needed only for immunocompromised patients or those with severe or persistent symptoms. Consideration of the patient's clinical presentation is recommended. Specialist medical advice is recommended for treatment.

Calprotectin helps differentiate active inflammatory bowel disease (IBD) from irritable bowel syndrome (IBS) and is used to monitor disease activity and predict relapse in conditions like IBD and colorectal cancer. Elevated levels may also result from bacterial diarrhoea, C. difficile toxin and NSAID use. High calprotectin warrants further investigation if the cause is unknown.

Lactoferrin is used to monitor disease activity and treatment response and to predict relapse in inflammatory bowel disease (IBD). Elevated levels may also result from bacterial diarrhoea or C. difficile toxin. High lactoferrin warrants further investigation if the cause is unknown.

A positive faecal occult blood test, often associated with colorectal cancer and inflammatory bowel disease (IBD), warrants further investigation if the cause is unknown.

Pancreatic elastase is used to assess exocrine pancreatic function in conditions like cystic fibrosis, diabetes, and chronic pancreatitis. In such cases, it is recommended to also consider clinical symptoms and other diagnostic tests for the final diagnosis. Liquid stools may yield falsely low results.

Low secretory IgA < 500 µg/ml may occur in obese patients with elevated fasting blood glucose. High secretory IgA > 2000 µg/ml may occur in intestinal inflammation, intestinal permeability, IBS-D, and autoimmune conditions. Interpretation should be made in the context of the patient's clinical presentation.

Zonulin Family Peptides is a marker of increased intestinal permeability. Elevated zonulin levels may occur in active celiac disease, type 1 diabetes, metabolic syndrome, obesity, autoimmune and inflammatory diseases, neoplastic conditions, high faecal histamine, intense exercise, or acute stress. Results should be interpreted in the context of the patient's clinical presentation.

Faecal acid-base balance. Low faecal pH may indicate rapid gut transit time while high pH may indicate slower transit.