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Our Tests Gut Health Assessment

Yeast Detection

Stool Test:

Yeast Culture

Description/Background Information

While the human microbiota is made up mostly of bacterial species, everybody carries some fungal species too — a much smaller component of the microbiota, separately referred to as the “mycobiota.”1,2 In healthy individuals, these fungi cause no problem. However, when the gut microbiota is upset by antibiotics, chemotherapy, or immunosuppressive drugs, or the immune system is compromised, certain fungi can become opportunistic and pathogenic.

Diseases caused by overgrowth of indigenous yeast species, such as Candida albicans (C. albicans), are a major cause of illness and death in critical care settings, and also play a significant role in a growing number of chronic diseases affecting the general population.2

The Salveo Diagnostics yeast culture test detects yeast in the stool and can differentiate Candida from non-Candida species, and also C. albicans from other Candida species, with high accuracy. Identification of yeast is performed by observing various factors including colony morphology, rate of growth, and color on selective media according to standard microbiological methods.3 Identification of C. albicans in Candida-positive samples is performed by a rapid colorimetric enzymatic assay.

Clinical Utility & Indications

The yeasts and fungi that make up the gut mycobiota are influenced by diet and interactions with other microorganisms (mainly bacteria) that are present. Saccharomyces and Candida are the two most prevalent yeast genera in stool samples of healthy individuals, and are positively associated with high carbohydrate consumption but negatively with diets high in protein and fats.4 The abundance of Saccharomyces may be due to its ubiquity in food and drink, whereas several Candida species are resident in the gut of most humans.2

A healthy immune system is crucial for maintenance of a balanced myco- and microbiota. However, if the immune system is dysregulated, Candida (most often C. albicans) in the gut may mutate to its filamentous (hyphal) form and penetrate the gut barrier, leading to intestinal permeability and the potential for systemic chronic diseases. The concomitant recruitment of neutrophils and release of cytokines may result in elevated fecal secretory IgA and calprotectin upon Salveo Gut Health Stool Assessment of patients with gastrointestinal yeast infections.

Factors that may promote Candida overgrowth in the gut5,6

  • Bacterial dysbiosis or infection
  • Metabolic diseases (e.g., diabetes mellitus),
  • Certain medications (e.g., corticosteroids, antibiotics, oral contraceptives),
  • Immunodeficiency/immunosuppression (e.g., HIV, chemotherapy, stress, autoimmune diseases)
  • Age (elderly, infancy)
  • Shifts in pH and malnutrition (e.g., standard Western diet with excess simple sugars and refined carbohydrates)

Generally, fungal infections due to Candida overgrowth are referred to as candidiasis, which underlies a wide array of clinical symptoms encompassing superficial, local, and systemic infections and which can exacerbate various digestive disorders, e.g., inflammatory bowel disease, irritable bowel syndrome, and peptic ulcers.6-9

Symptoms of Candida overgrowth in the gut6,10,11

  • Disabling fatigue and/or headaches
  • Mood and cognitive issues (e.g., anxiety/depression, irritability, difficulty focusing, memory deficits)
  • Skin disorders (e.g., dry, itchy skin, rashes)
  • Digestive issues (e.g., constipation, diarrhea, bloating, burping/flatulence)
  • Endocrine and inflammatory disorders
  • Consequences of damage to the intestinal mucosa — nutrient malabsorption, food sensitivities, and autoimmune disorders

Identification and semi-quantification of viable yeast by culturing the stool of symptomatic patients may confirm pathogenic levels and facilitate targeted treatment to heal and rebalance the gut microbiota. However, it is important to note certain caveats to definitive quantitation of yeast in the gut:2

  • Fungal growth inhibitors may be present to different extents in feces (stool) from different patients
  • Culture techniques may be inadequate to optimally cultivate all fungal species in the stool (e.g., those that are out-competed by fast-growing species or that require specific microbial interactions for growth)
  • Fast-growing species may become dominant during transport to the lab if the stool samples are not kept cool

Yeast Culture Cut Points & Interpretation

Quantification scale (0, 1+, 2+, 3+, 4+) refers to yeast colony growth rating, i.e., species abundance

Candida albicans

Optimal Mildly Elevated High
0 or 1+ 2+ 3+ or 4+

 

Non-Candida albicans

Optimal Mildly Elevated High
0 or 1+ or 2+ 3+ 4+

 

References

  1. Huffnagle GB, Noverr MC. Trends Microbiol2013;21(7):334-341.
  2. Suhr MJ, Hallen-Adams HE. Mycologia2015;107(6):1057-1073.
  3. Delost MD. Introduction to diagnostic microbiology for the laboratory sciences. 1st ed. Burlington, MA: Jones & Bartlett Learning; 2014.
  4. Hoffman C, et al. PLoS One 2013;8:e66019.
  5. Neville BA, et al. FEMS Yeast Res2015;15(7):fov081.
  6. Romani L. Nat Rev Immunol 2011;11:275–288.
  7. Liguori G, et al. J Crohn’s Colitis 2016;296–305.
  8. Wang ZK, et al. Aliment Pharmacol Ther2014;39:751–766.
  9. Hoarou G, et al. mBio 7(5):e01250–16.
  10. Corouge M, et al. PLoS One2015;20;10(3):e0121776.
  11. Hoffmann C, et al. PLoS One 2013;8:e66019.
  12. Dhamgaye S, et al. PLoS One 2014;9(8):e104554.
  13. Omura Y, et al. Acupunct Electrother Res2011;36(1-2):19–64.
  14. Bona E, et al. J Appl Microbiol 2016 Aug 29. doi: 10.1111/jam.13282.
  15. Li W-R, et al. Sci Rep 2016;6:22805.
  16. Masako P, Makgapeetja DM. BMC Complement Altern Med 2015;15:409.
  17. Gouba, N, Drancourt M. Med Mal Infect2015;45(1-2):9–16.
  18. Matsubara VH, et al. Clin Infect Dis2016;62(9):1143–1153.
  19. Noverr MC, Huffnagle GB. Infect Immun2004;72(11):6206–6210.

Serum Test:

Anti-Candida Antibodies

Description/Background Information

Candida albicans (C. albicans) is a benign yeast commonly found on mucosal surfaces of the human body (e.g., mouth, digestive system, urogenital tract, and skin). Transmitted from mother to infant during birth, it forms part of the commensal gastrointestinal “mycobiota” in approximately half of the world’s population.1 The colonization and amount of Candida and other yeast species in the gut is regulated by interactions with the host’s immune system and the intestinal microbiota. A fine balance between resistance to fungal overgrowth (release of pro-inflammatory signals) and tolerance (release of anti-inflammatory signals, to prevent mucosal damage caused by the immune response) is required to maintain a healthy gut microbial community.2,3

Although harmless most of the time, C. albicans is an opportunistic species under certain conditions, such as long-term antibiotic treatment and compromised immune function (suppressed immune system or disrupted barrier defenses).2When it mutates from its yeast (unicellular) form to its fungal (filamentous) form in the gut, C. albicans can become invasive and crowd out beneficial microbial species to create an imbalance (dysbiosis) in the resident microbiota. It also produces toxins that can damage the gut lining, leading to intestinal permeability, inflammation, and an activated immune response.4 It is the most pathogenic Candida species and is well-known for its potential to cause fatal systemic infections in susceptible patients. However, C. albicans overgrowth in the gut can also underlie a myriad of chronic diseases in the general population.3,5-7

Clinical Utility & Indications

The intestinal epithelium cells are able to distinguish between benign C. albicansin its yeast form and the harmful fungal form.4 To protect against fungal infection when C. albicans levels start to exceed healthy limits, cytokines are released, neutrophils are activated, and immune cells are recruited, to assist in returning the gut mycobiota (and microbiota) to a state of balance (these processes mean that a Salveo Diagnostics Gut Health Stool Assessment may show elevated fecal secretory IgA and calprotectin in patients with C. albicans infections). If the immune system is depleted for any reason, then C. albicans may be able to penetrate the gut barrier and elicit the formation of antibodies that circulate in the blood.

Factors that may promote Candida overgrowth in the gut 2,3

  • Bacterial dysbiosis or infection
  • Metabolic diseases (e.g., diabetes mellitus),
  • Certain medications (e.g., corticosteroids, antibiotics, oral contraceptives),
  • Immunodeficiency/immunosuppression (e.g., HIV, chemotherapy, stress, autoimmune diseases)
  • Age (elderly, infancy)
  • Shifts in pH and malnutrition (e.g., standard Western diet with excess simple sugars and refined carbohydrates)

Generally, fungal infections due to Candida overgrowth are referred to as candidiasis, which underlies a wide array of clinical symptoms encompassing superficial, local, and systemic infections, and which can exacerbate various digestive disorders, e.g., inflammatory bowel disease, irritable bowel syndrome, and peptic ulcers.3,5,8,9

Symptoms of Candida overgrowth in the gut3,6,10

  • Disabling fatigue and/or headaches
  • Mood and cognitive issues (e.g., anxiety/depression, irritability, difficulty focusing, memory deficits)
  • Skin disorders (e.g., dry, itchy skin, rashes)
  • Digestive issues (e.g., constipation, diarrhea, bloating, burping/flatulence)
  • Endocrine and inflammatory disorders
  • Consequences of damage to the intestinal mucosa — nutrient malabsorption, food sensitivities, and autoimmune disorders

Anti-Candida Antibodies Cut Points & Interpretation

Optimal Undetermined High
< 9 U 9-11 U > 11 U

 Detection of serum antibodies to C. albicans in symptomatic patients may confirm pathogenic levels of this yeast and facilitate targeted treatment to heal and rebalance the gut microbiota. The different antibody (immunoglobulin) subclasses reflect different, sometimes overlapping, types of immune response:

  • IgM is the first antibody formed after exposure to an antigen. IgM readily activates complement to trigger antigen clearance from the blood and is generally the predominant immunoglobin involved in early infections.
  • IgA is found in mucous secretions and is important in local (mucosal) immunity. IgA elevations would indicate yeast overgrowth on skin or in mucous membranes such as vaginal epithelium or digestive tract. In patients who have IgA deficiency, the anti-Candida IgA value may be falsely low. If a patient has suggestive symptoms, a stool yeast assessment may verify Candida overgrowth in the gut.
  • IgG reflects a past or ongoing infection and is produced as IgM antibody levels fall after a primary exposure. IgG positivity can persist for more than a year so serial measurements to document reduced titers would be indicative of past or treated infections.

References

  1. Gouba, N, Drancourt M. Med Mal Infect 2015;45(1-2):9–16.
  2. Neville BA, et al. FEMS Yeast Res 2015;15(7):fov081.
  3. Romani L. Nat Rev Immunol 2011;11:275–288.
  4. Naglik JR, et al. Microbes Infect 2011;13:963–976.
  5. Liguori G, et al. J Crohn’s Colitis 2016;296–305.
  6. Corouge M, et al. PLoS One 2015;20;10(3):e0121776.
  7. Pasini E, et al. JACC Heart Fail 2016;4(3):220–227.
  8. Wang ZK, et al. Aliment Pharmacol Ther 2014;39:751–766.
  9. Hoarou G, et al. mBio 7(5):e01250–16.
  10. Hoffmann C, et al. PLoS One 2013;8:e66019.
  11. Dhamgaye S, et al. PLoS One 2014;9(8):e104554.
  12. Omura Y, et al. Acupunct Electrother Res 2011;36(1-2):19–64.
  13. Bona E, et al. J Appl Microbiol 2016 Aug 29. doi: 10.1111/jam.13282.
  14. Li W-R, et al. Sci Rep 2016;6:22805.
  15. Masako P, Makgapeetja DM. BMC Complement Altern Med 2015;15:409
  16. Matsubara VH, et al. Clin Infect Dis 2016;62(9):1143–1153.
  17. Noverr MC, Huffnagle GB. Infect Immun 2004;72(11):6206–6210.
  18. Coondoo A, et al. Indian Dermatol Online J 2014;5(4):416–425