SIBO: The Leading Cause of IBS

Could treating small intestinal bacterial overgrowth be the answer IBS sufferers are looking for?

SIBO: The Leading Cause of IBS  photo

SIBO, or small intestinal bacterial overgrowth, is a type of condition affecting the gut. It often goes undiagnosed as the symptoms can overlap with those of IBS, or irritable bowel syndrome, a type of functional bowel disorder. Recent evidence estimates that over one-third of IBS sufferers test positive for SIBO. However, it can be associated with other clinical conditions and, left untreated, SIBO increases the risk of serious health issues.1,2

Treatment of SIBO often presents a challenge, particularly in those with recurrent relapses. Confirming SIBO with appropriate testing and assessing the individual’s history and symptoms to assess underlying factors can enable effective, personalised therapy using a combination of dietary, lifestyle and nutraceutical approaches.3,4

This article explores SIBO, the myriad of symptoms, potential causes and underlying factors contributing to the condition and the various treatment options available.

What is SIBO?

SIBO is a condition affecting the small intestine which occurs when bacteria that are normally present in other parts of the gut start to over-grow in the small intestine. Some of the bacteria may be healthy, but often they are pathogenic bacteria that have migrated from the large intestine.3,5

SIBO is considered a malabsorptive condition as a result of gut stasis, meaning that there is stagnation in the small intestine due to slow gut motility.3,5

Gut bacteria have many important roles in the body, one of the main ones being to aid digestion. They ferment carbohydrates from our diet, producing natural by-products of gas, typically methane and hydrogen. Whereas this process normally happens in the large intestine, in SIBO the gas builds up in the small intestine instead, which leads to uncomfortable and distressing symptoms.6

Signs and symptoms of SIBO

There can be many different symptoms associated with SIBO, and the most common ones include:2,5,7,8,9

  • Diarrhoea and/or constipation
  • Sensation of fullness after eating
  • Bloating, particularly higher up in the abdominal area
  • Abdominal pain
  • Flatulence
  • Reflux
  • Nausea

However, other non-gastrointestinal symptoms which people may not realise are related to SIBO include brain fog, anxiety and low mood, aching joints, fatigue and weight loss.

Types of SIBO

There are different types of SIBO which vary in their characteristic symptoms and types of gas produced. These include:2,6,7

Hydrogen-dominant SIBO

Hydrogen-producing bacteria ferment carbohydrates, increase gut transit time and cause diarrhoea.

Intestinal methanogen overgrowth (IMO)

Methane-producing Archaea (ancient micro-organisms), such as Methanobrevibacter smithii, decrease gut transit time and cause constipation.

Combined SIBO

Hydrogen-producing bacteria and methane-producing Archaea are present in the small intestine, resulting in mixed symptoms, such as alternating diarrhoea and constipation.

Hydrogen sulphide SIBO

Less common than other types of SIBO, partly due to the fact that there are no direct tests available in the UK currently. However, there is now a test available in the US called Trio-Smart ( which measures for hydrogen, methane and hydrogen-sulphide. Tell-tale signs of hydrogen-sulphide SIBO include constipation, abdominal pain and bloating, sulphur-smelling flatulence, bladder pain and heartburn.

Hydrogen-producing bacterial overgrowth accounts for nearly 50% of SIBO cases, methane overgrowth at just under 40%, and the remaining cases producing both hydrogen and methane gases.

What causes SIBO?

Whilst there are clear links between SIBO and IBS, there can be many other causes. Often it is a combination of factors causing poor gut motility, digestive dysfunction, impaired gut lining and an imbalance of gut bacteria, known as dysbiosis.1,2,5,7,9,10,11

Slow gut motility and intestinal flow: factors affecting the movement of food through the gastrointestinal tract include damage to the vagal nerve, auto-immune disorders, endometriosis, adhesions, abdominal or gastric bypass surgery, impaired thyroid function or poor mental wellbeing.

Poor digestion: insufficient digestive enzymes, low stomach acid and low levels of bile allow for growth of unhealthy bacteria. Common factors include gallbladder removal, lack of chewing or eating on the go, stress and poor dental hygiene.

Dysbiosis: an imbalance of gut bacteria, where healthy bacteria are crowded out by pathogenic bacteria. Factors include antibiotic treatments, a diet high in sugars and refined, processed carbohydrates, low fibre intake, stress, gastritis, Helicobacter pylori or a food-borne infection.

Medications: PPIs such as omeprazole, non-steroidal anti-inflammatories and antibiotics are known to influence digestion and the microbiome.

Compromised immune system: associated diseases such as Coeliac disease, inflammatory bowel disorder, low thyroid function, rheumatoid arthritis or other immune system disorders. These can lead to inflammation, altered gut motility, impaired gut lining, malabsorption and subsequent SIBO.

Who is more at risk of developing SIBO?

IBS sufferers carry a five-fold risk of developing SIBO, with increased odds in the female gender, older age and those presenting with diarrhoea.1

Conditions most commonly associated with a higher risk of SIBO include, but are not limited to:2,5,9,10,12

  • Irritable bowel syndrome, Coeliac disease, Crohn’s disease and ulcerative colitis
  • Gastroenteritis or a food-borne illness
  • Food sensitivities or intolerances
  • Peptic ulcer, diverticular disease, low stomach acid or Helicobacter Pylori infection
  • Rheumatological conditions such as systemic sclerosis, rheumatoid arthritis or Behcet’s disease
  • Dermatological disease such as rosacea, pyoderma faciale and psoriasis
  • Hypothyroidism
  • Chronic fatigue syndrome or fibromyalgia
  • Parkinson’s disease or other neurological disorders
  • Liver dysfunction or fatty liver disease
  • Obesity and associated conditions such as high blood pressure, blood sugar and cholesterol
  • Diabetes
  • Vitamin B12 deficiency or anaemia
  • Mental health disorders

SIBO testing

The most common way to test for SIBO is using lactulose and/or glucose breath testing. This measures how much methane and hydrogen gas is being produced in the small intestine and is easily performed at home.2,10

Lactulose breath test

Hydrogen and methane gases are measured in response to oral administration of lactulose (a type of sugar consisting of fructose and galactose). If bacteria start to break down lactulose in the small intestine before it enters the large intestine at around 90 minutes, there will be an increased production of hydrogen and/or methane gas which would confirm a positive test. Once lactulose reaches the large intestine, it is normal to see a second increase in the production of gas.

Glucose breath test

Hydrogen and methane gases are measured in response to oral administration of glucose (a simple monosaccharide sugar). As with the lactulose breath test, if the bacteria start to break down glucose in the small intestine, gas will be produced, resulting in a positive diagnosis of SIBO.

How to interpret breath test results

A positive SIBO test shows an increase from the basal rate within 90 minutes of 20 ppm (parts per million) for hydrogen, 12 ppm for methane or a combined measurement of 15 ppm for both hydrogen and methane. If constipation was noted at the time of testing and the methane gas measurement is greater than 3 ppm, then a practitioner may also consider this a positive test.13,14,15,16

If the test shows a flat line over the three hours of testing, this could indicate hydrogen sulphide SIBO, but direct testing for this is only currently available in the US via Trio-Smart. The prac titioner will carefully assess the results and clinical presentation to decide whether treatment is indicated.16

What is the difference between the glucose and lactulose breath test?

The main difference between lactulose and glucose breath testing is that glucose is absorbed more quickly than lactulose and doesn’t always reach the distal section of small intestine.

A glucose test rarely gives false-positive results, but because SIBO can be lower down in the small intestine, it could produce a false-negative result.

A lactulose test rarely gives false-negative results, but because it can travel through the small intestine quickly, for example if the person has diarrhoea, it could lead to a false-positive result.

For best results, it may be prudent to test with glucose and lactulose to assess the whole of the small intestine and reduce the risk of false-negative results.16

Are there other ways to diagnose SIBO?

Other tests can indicate whether someone potentially has SIBO, however they do not clearly define which type and so a subsequent breath test would still be advised to enable effective therapy.

Small intestinal aspiration and culture

This is considered the gold standard of testing which involves taking some bacteria from the small intestine and growing it in a petri dish. However it is expensive, there can be issues with bacterial contamination and it tends to only be used rarely in some clinical research settings.2,10,16,17

Faecal calprotectin

Research is currently looking at the association between faecal calprotectin, a stool test used to measure levels of inflammation, and the prevalence of SIBO in rheumatic disease such as systemic sclerosis. It is suggested that this could serve as a quick, non-invasive and relatively cheap diagnostic tool for SIBO.18.19

Organic acids testing

This nutrient evaluation test can be used to assess metabolic biomarkers in the urine and can be performed easily at home. If elevated levels of 4-hydroxyphenylacetate are present (a by-product of specific Clostridia bacteria), this may indicate SIBO or other small bowel disorders.16,20

Comprehensive stool test analysis

This home test can provide useful markers for SIBO and digestive capacity. Specific indicators to watch for include:21

  • Pancreatic elastase to assess digestive enzyme production and absorption
  • Overgrowth of particular bacterial species, such as Methanobrevibacter smithii, Desulfovibrio piger and Bilophila wadsworthia which are well-known methane and hydrogen sulphide producing bacteria
  • A pattern of dysbiosis where healthy bacteria are crowded out by pathogenic bacteria
  • A high growth of E coli, Klebsiella, Proteus, Bacteroides or Clostridium species

What treatments are available for SIBO?

There are several different treatment options for SIBO. Effective eradication typically involves a combination of antibiotic or antimicrobial therapy, low fermentable-carbohydrate diet and nutraceuticals to support healthy digestion and a balanced microbiome. Addressing the underlying factors is key to minimising the risk of relapse.18

Antibiotic therapy

Rifaximin has been widely researched and used as a safe and effective antibiotic therapy for SIBO as it only absorbs in the small intestine and is less likely to affect the balance of the large intestinal bacteria. This is generally administered for between 10 and 14 days. However, there may be a higher risk of relapse with antibiotic treatment.12,24,25,26

Herbal antimicrobial therapy

Herbal anti-microbials have gained popularity as a cheaper, safe and equally effective alternative to antibiotic therapy.

A combination of herbal antimicrobials should be considered for eradication of SIBO, depending on which type you have. These are taken for around 6 to 10 weeks, depending on symptom response. These include:

  • Oregano
  • Berberine
  • Allicin
  • Neem

Oil of oregano and berberine are herbs commonly used to target hydrogen-producing bacteria, whilst allicin (garlic extract) is effective in killing off methane-producing bacteria. Neem is another herbal preparation which is beneficial in eradicating pathogenic bacteria involved in SIBO.11,23,24

Low-fermentable carbohydrate diet

Specific fermentable carbohydrates which are usually considered part of a healthy diet, can be problematic in SIBO because they feed the bacteria which are growing in the small intestine. By starving them, it helps to stop their overgrowth. Several different diets use this principle (such as the low FODMAP or biphasic diet) with the main foods to avoid being:

  • Grains
  • Pulses
  • Fruits and vegetables with a naturally high sugar content

This type of elimination diet is generally used alongside antimicrobial therapy for up to 12 to 16 weeks. Foods are then reintroduced gradually at the end of therapy to avoid nutrient insufficiency and deficiency and to help encourage repopulation and diversity of healthy gut bacteria.10, 16, 27

What lifestyle changes can help to eradicate and prevent SIBO?

Identifying underlying factors is crucial to help eradicate and prevent the relapse of SIBO. Lifestyle or therapeutic strategies may involve:10,11,28

  • Correcting nutritional deficiencies, such as vitamin B12 deficiency
  • Avoiding stress and using coping strategies to help alleviate the ‘fight or flight’ response in the body
  • Exercising regularly to stay active and help support healthy digestion, gut motility and improve mood
  • Eating a well-balanced, healthy diet such as the Mediterranean diet which is well-evidenced for its ability to reduce inflammation and provide a wide diversity of essential nutrients for whole body function
  • Removing potential food triggers, such as gluten or dairy, which commonly cause food intolerances and sensitivities
  • Avoiding or reducing alcohol intake
  • Supporting gut motility by stimulating the vagus nerve using simple techniques such as singing, humming and gargling
  • Visceral manipulation to help reduce adhesions and scar formation such as with endometriosis, laparoscopy, appendicectomy or other abdominal surgery

Additional nutraceutical considerations for SIBO

Nutraceutical supplements to aid digestion and motility, calm inflammation, support the gut lining, replenish essential nutrients and encourage a healthy diversity of gut bacteria are important factors in the treatment of SIBO. Common supplements used, depending on the individuals needs include:

  • Digestive enzymes with or without hydrochloric acid: to be taken with each meal to help breakdown foods and support healthy digestion and absorption of nutrients.29-31
  • Saccharomyces boulardii: a form of probiotic yeast that is well-tolerated in those with a sensitive gut. Found to be beneficial in alleviating diarrhoea and symptoms of IBS. It binds to pathogens in the gut to remove them from the body and supports gut immunity. Can be taken throughout the course of SIBO therapy.32
  • Gastrointestinal support: Supplement complexes to soothe an inflamed gut and to heal and protect the gut lining should be considered. Important nutrients to look out for include L-glutamine, slippery elm, aloe vera, pectin, marshmallow root, vitamin A and vitamin D.33-35
  • PHGG: Partially hydrolyzed guar gum is a well-tolerated, safe and effective form of prebiotic dietary fibre helps to regulate bowel movements, supports gut motility and encourages healthy growth of beneficial bacteria such as Bifidobacteria and Lactobacilli. When taken in combination with Rifaximin, it had a success rate of 87.1% in eradicating SIBO, in comparison with 62.1% in those on Rifaximin alone.36,37
  • NAC (N-acetyl cysteine): the supplement form of an essential amino acid, cysteine. In SIBO therapy it supports detoxification and alleviates symptoms of ‘die off’ during the active phase of treatment when bacteria are killed off and eliminated from the body. It also helps to disrupt stubborn biofilms which can form when pathogenic bacteria start to clump together, which is a particular consideration for those with long-term, chronic and relapsing SIBO.38,39
  • Prokinetics: Prokinetics can be used during the active phase of SIBO therapy, or immediately afterwards to encourage healthy gut motility. This ensures that food moves through digestive system appropriately and does not stagnate in the small intestine, which would otherwise increase the risk of overgrowth and relapse of SIBO. Prokinetics should be used in conjunction with other lifestyle measures to help improve gut motility.40,41
  • Probiotics: During SIBO eradication, healthy bacteria are starved and killed off along with pathogenic ones in order to clear them from the small intestine. It’s therefore essential to repopulate the gut with a wide diversity of healthy bacteria to ensure good gut health going forward. Choose a broad-spectrum probiotic with good levels of a diverse array of species, including Lactobacillus and Bifidobacterium.42,43
  • Multi-nutrients: Correct any nutritional deficiencies such as vitamin B12, iron, calcium or fat-soluble vitamins A, D, E and K. A qualified practitioner will be able to advise on whether to take a specific vitamin or a broad spectrum multi-nutrient formula.10

Key takeaways for SIBO

SIBO can be a difficult condition to treat and overwhelming due to its complexities. Consulting with a qualified SIBO practitioner or registered Nutritional Therapy can provide tailored support to guide you through successful therapy and help lessen the risk of relapse in the future.

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  1. Chen, B., Kim, J. J., Zhang, Y., Du, L., & Dai, N. (2018). Prevalence and predictors of small intestinal bacterial overgrowth in irritable bowel syndrome: a systematic review and meta-analysis. Journal of gastroenterology, 53(7), 807–818.
  2. Takakura, W., & Pimentel, M. (2020). Small Intestinal Bacterial Overgrowth and Irritable Bowel Syndrome - An Update. Frontiers in psychiatry, 11, 664.
  3. Adike, A., & DiBaise, J. K. (2018). Small Intestinal Bacterial Overgrowth: Nutritional Implications, Diagnosis, and Management. Gastroenterology clinics of North America, 47(1), 193–208.
  4. Ruscio M. (2019). Is SIBO A Real Condition?. Alternative therapies in health and medicine, 25(5), 30–38.
  5. Miazga, A., Osiński, M., Cichy, W., & Żaba, R. (2015). Current views on the etiopathogenesis, clinical manifestation, diagnostics, treatment and correlation with other nosological entities of SIBO. Advances in medical sciences, 60(1), 118–124.
  6. Jahng, J., Jung, I. S., Choi, E. J., Conklin, J. L., & Park, H. (2012). The effects of methane and hydrogen gases produced by enteric bacteria on ileal motility and colonic transit time. Neurogastroenterology and motility : the official journal of the European Gastrointestinal Motility Society, 24(2), 185–e92.
  7. Ghoshal, U. C., Shukla, R., & Ghoshal, U. (2017). Small Intestinal Bacterial Overgrowth and Irritable Bowel Syndrome: A Bridge between Functional Organic Dichotomy. Gut and liver, 11(2), 196–208.
  8. Simeonova, D., Ivanovska, M., Murdjeva, M., Carvalho, A. F., & Maes, M. (2018). Recognizing the Leaky Gut as a Trans-diagnostic Target for Neuroimmune Disorders Using Clinical Chemistry and Molecular Immunology Assays. Current topics in medicinal chemistry, 18(19), 1641–1655.
  9. Madigan, K. E., Bundy, R., & Weinberg, R. B. (2021). Distinctive Clinical Correlates of Small Intestinal Bacterial Overgrowth with Methanogens. Clinical gastroenterology and hepatology : the official clinical practice journal of the American Gastroenterological Association, S1542-3565(21)01049-1. Advance online publication.
  10. Bures, J., Cyrany, J., Kohoutova, D., Förstl, M., Rejchrt, S., Kvetina, J., Vorisek, V., & Kopacova, M. (2010). Small intestinal bacterial overgrowth syndrome. World journal of gastroenterology, 16(24), 2978–2990.
  11. James,M. (2020) ‘Bacterial Overgrowth of the Small Intestine Breath Test’: in Pizzorno, J. and Murray, M. Textbook of Natural Medicine E-Book, 4th Edn, Chapter 10, pp.108-113. Elsevier: Missouri.
  12. Losurdo, G., Salvatore D'Abramo, F., Indellicati, G., Lillo, C., Ierardi, E., & Di Leo, A. (2020). The Influence of Small Intestinal Bacterial Overgrowth in Digestive and Extra-Intestinal Disorders. International journal of molecular sciences, 21(10), 3531.
  13. Ghoshal U. C. (2011). How to interpret hydrogen breath tests. Journal of neurogastroenterology and motility, 17(3), 312–317.
  17. Rezaie, A., Pimentel, M., & Rao, S. S. (2016). How to Test and Treat Small Intestinal Bacterial Overgrowth: an Evidence-Based Approach. Current gastroenterology reports, 18(2), 8.
  18. Polkowska-Pruszyńska, B., Gerkowicz, A., Rawicz-Pruszyński, K., & Krasowska, D. (2020). The Role of Fecal Calprotectin in Patients with Systemic Sclerosis and Small Intestinal Bacterial Overgrowth (SIBO). Diagnostics (Basel, Switzerland), 10(8), 587.
  19. Andréasson, K., Scheja, A., Saxne, T., Ohlsson, B., & Hesselstrand, R. (2011). Faecal calprotectin: a biomarker of gastrointestinal disease in systemic sclerosis. Journal of internal medicine, 270(1), 50–57.
  22. Gatta, L., & Scarpignato, C. (2017). Systematic review with meta-analysis: rifaximin is effective and safe for the treatment of small intestine bacterial overgrowth. Alimentary pharmacology & therapeutics, 45(5), 604–616.
  23. Chedid, V., Dhalla, S., Clarke, J. O., Roland, B. C., Dunbar, K. B., Koh, J., Justino, E., Tomakin, E., & Mullin, G. E. (2014). Herbal therapy is equivalent to rifaximin for the treatment of small intestinal bacterial overgrowth. Global advances in health and medicine, 3(3), 16–24.
  25. Kwiatkowski, L., Rice, E., & Langland, J. (2017). Integrative Treatment of Chronic Abdominal Bloating and Pain Associated With Overgrowth of Small Intestinal Bacteria: A Case Report. Alternative therapies in health and medicine, 23(4), 56–61.
  26. Saffouri, G. B., Shields-Cutler, R. R., Chen, J., Yang, Y., Lekatz, H. R., Hale, V. L., Cho, J. M., Battaglioli, E. J., Bhattarai, Y., Thompson, K. J., Kalari, K. K., Behera, G., Berry, J. C., Peters, S. A., Patel, R., Schuetz, A. N., Faith, J. J., Camilleri, M., Sonnenburg, J. L., Farrugia, G., … Kashyap, P. C. (2019). Small intestinal microbial dysbiosis underlies symptoms associated with functional gastrointestinal disorders. Nature communications, 10(1), 2012.
  27. Leonardi, M., Hicks, C., El-Assaad, F., El-Omar, E., & Condous, G. (2020). Endometriosis and the microbiome: a systematic review. BJOG : an international journal of obstetrics and gynaecology, 127(2), 239–249.
  28. Ponziani, F. R., Zocco, M. A., D'Aversa, F., Pompili, M., & Gasbarrini, A. (2017). Eubiotic properties of rifaximin: Disruption of the traditional concepts in gut microbiota modulation. World journal of gastroenterology, 23(25), 4491–4499.
  29. Ianiro, G., Pecere, S., Giorgio, V., Gasbarrini, A., & Cammarota, G. (2016). Digestive Enzyme Supplementation in Gastrointestinal Diseases. Current drug metabolism, 17(2), 187–193.
  30. Lee, A. A., Baker, J. R., Wamsteker, E. J., Saad, R., & DiMagno, M. J. (2019). Small Intestinal Bacterial Overgrowth Is Common in Chronic Pancreatitis and Associates With Diabetes, Chronic Pancreatitis Severity, Low Zinc Levels, and Opiate Use. The American journal of gastroenterology, 114(7), 1163–1171.
  31. Therrien, A., Bouchard, S., Sidani, S., & Bouin, M. (2016). Prevalence of Small Intestinal Bacterial Overgrowth among Chronic Pancreatitis Patients: A Case-Control Study. Canadian journal of gastroenterology & hepatology, 2016, 7424831.
  32. Bafutto M, Almeida JR, Leite NV, Costa MB, Oliveira EC, Resende-Filho J. Treatment of diarrhea-predominant irritable bowel syndrome with mesalazine and/or Saccharomyces boulardii. Arq Gastroenterol. 2013 Oct-Dec;50(4):304-9. doi: 10.1590/S0004-28032013000400012. PMID: 24474234.
  33. Kim, M. H., & Kim, H. (2017). The Roles of Glutamine in the Intestine and Its Implication in Intestinal Diseases. International journal of molecular sciences, 18(5), 1051.
  34. Cantorna, M. T., Snyder, L., & Arora, J. (2019). Vitamin A and vitamin D regulate the microbial complexity, barrier function, and the mucosal immune responses to ensure intestinal homeostasis. Critical reviews in biochemistry and molecular biology, 54(2), 184–192.
  35. Ried K, Travica N, Dorairaj R, Sali A. Herbal formula improves upper and lower gastrointestinal symptoms and gut health in Australian adults with digestive disorders. Nutr Res. 2020 Apr;76:37-51. doi: 10.1016/j.nutres.2020.02.008. Epub 2020 Feb 8. PMID: 32151878.
  36. Niv, E., Halak, A., Tiommny, E., Yanai, H., Strul, H., Naftali, T., & Vaisman, N. (2016). Randomized clinical study: Partially hydrolyzed guar gum (PHGG) versus placebo in the treatment of patients with irritable bowel syndrome. Nutrition & metabolism, 13, 10.
  37. Furnari M, Parodi A, Gemignani L, Giannini EG, Marenco S, Savarino E, Assandri L, Fazio V, Bonfanti D, Inferrera S, Savarino V. Clinical trial: the combination of rifaximin with partially hydrolysed guar gum is more effective than rifaximin alone in eradicating small intestinal bacterial overgrowth. Aliment Pharmacol Ther. 2010 Oct;32(8):1000-6. doi: 10.1111/j.1365-2036.2010.04436.x. Epub 2010 Aug 18. PMID: 20937045.
  38. Koo, H., Allan, R. N., Howlin, R. P., Stoodley, P., & Hall-Stoodley, L. (2017). Targeting microbial biofilms: current and prospective therapeutic strategies. Nature reviews. Microbiology, 15(12), 740–755.
  39. Kundukad, B., Udayakumar, G., Grela, E., Kaur, D., Rice, S. A., Kjelleberg, S., & Doyle, P. S. (2020). Weak acids as an alternative anti-microbial therapy. Biofilm, 2, 100019.
  40. Ghosh, G., & Jesudian, A. B. (2019). Small Intestinal Bacterial Overgrowth in Patients With Cirrhosis. Journal of clinical and experimental hepatology, 9(2), 257–267.
  41. Revaiah, P. C., Kochhar, R., Rana, S. V., Berry, N., Ashat, M., Dhaka, N., Rami Reddy, Y., & Sinha, S. K. (2018). Risk of small intestinal bacterial overgrowth in patients receiving proton pump inhibitors versus proton pump inhibitors plus prokinetics. JGH open : an open access journal of gastroenterology and hepatology, 2(2), 47–53.
  42. Klopper, K. B., Deane, S. M., & Dicks, L. (2018). Aciduric Strains of Lactobacillus reuteri and Lactobacillus rhamnosus, Isolated from Human Feces, Have Strong Adhesion and Aggregation Properties. Probiotics and antimicrobial proteins, 10(1), 89–97.
  43. Losurdo, G., Salvatore D'Abramo, F., Indellicati, G., Lillo, C., Ierardi, E., & Di Leo, A. (2020). The Influence of Small Intestinal Bacterial Overgrowth in Digestive and Extra-Intestinal Disorders. International journal of molecular sciences, 21(10), 3531.