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Table of Contents
SIBO Overview
How Common Is SIBO?
Causes and Risk Factors
Mortality
Early Detection
Thegut microbiotais the bacteria, viruses, and other organisms that normally live inside the digestive tract. When the amount of bacteria in the small intestine grows too large, or an abnormal type of bacteria grows there, it is calledsmall intestinal bacterial overgrowth (SIBO).
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SIBO Overview
SIBO may occur in people who have had surgery on their bowels, take certain medications, or live with certain medical conditions affecting the digestive system. There is no one standardized way to test or treat SIBO. In some cases, it may be diagnosed with a breath test and treated with antibiotics.
Some of the signs and symptoms of SIBO include:
SIBO is considered a common condition, but no reliable data exist on how many people are diagnosed and treated yearly. However, there is some information available on how often SIBO affects people with other digestive conditions.
One study found that for people with inactiveCrohn’s disease(meaning that various clinical tests showed no sign of disease activity in people previously diagnosed with the condition), 16.8% had SIBO. Crohn’s disease is an inflammatory bowel disease (IBD) that affects the lining of the digestive tract.
There is little data on the prevalence of SIBO across ethnicities in the United States. However, studies in different countries or areas of the world that include people with IBS show various rates of SIBO in those populations.
The rates of SIBO in people with IBS across studies are:
What has been shown is that anywhere from 13% to 35% of healthy people may have SIBO, depending on which test is used to diagnose the condition. Older people may be at greater risk for SIBO because they tend to have altered levels of gastric acid and may be more likely to receive a medication that increases the risk of SIBO.
Causes of SIBO and Risk Factors
Several conditions are associated with SIBO. Some of the more common ones include:
Medications might also be a risk factor or a cause of SIBO. Medications that are associated with SIBO include:
What Are the Mortality Rates for SIBO?
SIBO tends to be a complicating factor that goes along with other conditions. For that reason, it’s not considered a fatal disorder. But it is possible that it leads to worse outcomes for people already managing certain serious conditions.
For instance, one study on people with heart failure—a condition in which the heart doesn’t pump enough blood to meet the body’s needs—showed that SIBO is common and increases poor outcomes, like being readmitted to the hospital or risk of death.The authors of this study suggest that it’s worth treating SIBO in people with heart failure.
However, there’s little other data to guide decisions on who should be tested and treated for SIBO and how it might affect the risks of complications. The decision to test and treat for SIBO will be made between healthcare providers and patients.
Screening and Early Detection for SIBO
It can be challenging to diagnose SIBO because there are no accepted guidelines on who to test for SIBO and when. It is known that SIBO is common in people with certain conditions, such as those who live with Crohn’s disease or IBS.
However, many of the symptoms of SIBO are nonspecific and are similar to the symptoms of other conditions. People may need to talk with a healthcare provider about additional testing if a condition is being treated, but symptoms such as bloating, pain, and diarrhea are not improving.
Some of the ways totest for SIBOinclude:
Summary
SIBO is a common condition, but how many people it affects is still not well understood. It can result as a complication of various other diseases and conditions. People may want to seek a diagnosis or treatment if they are in a higher risk group and suspect SIBO.
6 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Rezaie A, Pimentel M, Rao SS.How to test and treat small intestinal bacterial overgrowth: An evidence-based approach.Curr Gastroenterol Rep.2016;18:8. doi:10.1007/s11894-015-0482-9.Lasa JS, Zubiaurre I, Fanjul I, Olivera P, Soifer L.Small intestinal bacterial overgrowth prevalence in celiac disease patients is similar in healthy subjects and lower in irritable bowel syndrome patients.Rev Gastroenterol Mex. 2015;80:171-174. doi:10.1016/j.rgmx.2015.04.002.Shah A, Talley NJ, Jones M, et al.Small intestinal bacterial overgrowth in irritable bowel syndrome: A systematic review and Meta-analysis of case-control studies.Am J Gastroenterol. 2020;115:190-201. doi:10.14309/ajg.0000000000000504.Sachdev AH, Pimentel M.Gastrointestinal bacterial overgrowth: pathogenesis and clinical significance.Ther Adv Chronic Dis. 2013;4:223-231. doi:10.1177/2040622313496126.Quigley EMM, Murray JA, Pimentel M.AGA Clinical practice update on small intestinal bacterial overgrowth: Expert review.Gastroenterology. 2020;159:1526-1532. doi:10.1053/j.gastro.2020.06.090.Song Y, Liu Y, Qi B, et al.Association of small intestinal bacterial overgrowth with heart failure and its prediction for short-term outcomes.J Am Heart Assoc. 2021;10:e015292. doi: 10.1161/JAHA.119.015292.Additional ReadingKrajicek EJ, Hansel SL.Small intestinal bacterial overgrowth: A primary care review.Mayo Clin Proc.2016;91:1828-1833. doi:10.1016/j.mayocp.2016.07.025.Pimentel M, Saad RJ, Long MD, Rao SSC.ACG clinical guideline: small intestinal bacterial overgrowth.Am J Gastroenterol. 2020;115:165-178. doi:10.14309/ajg.0000000000000501.Rao SSC, Bhagatwala J.Small intestinal bacterial overgrowth: Clinical features and therapeutic management.Clin Transl Gastroenterol. 2019;10:e00078. doi:10.14309/ctg.0000000000000078.
6 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Rezaie A, Pimentel M, Rao SS.How to test and treat small intestinal bacterial overgrowth: An evidence-based approach.Curr Gastroenterol Rep.2016;18:8. doi:10.1007/s11894-015-0482-9.Lasa JS, Zubiaurre I, Fanjul I, Olivera P, Soifer L.Small intestinal bacterial overgrowth prevalence in celiac disease patients is similar in healthy subjects and lower in irritable bowel syndrome patients.Rev Gastroenterol Mex. 2015;80:171-174. doi:10.1016/j.rgmx.2015.04.002.Shah A, Talley NJ, Jones M, et al.Small intestinal bacterial overgrowth in irritable bowel syndrome: A systematic review and Meta-analysis of case-control studies.Am J Gastroenterol. 2020;115:190-201. doi:10.14309/ajg.0000000000000504.Sachdev AH, Pimentel M.Gastrointestinal bacterial overgrowth: pathogenesis and clinical significance.Ther Adv Chronic Dis. 2013;4:223-231. doi:10.1177/2040622313496126.Quigley EMM, Murray JA, Pimentel M.AGA Clinical practice update on small intestinal bacterial overgrowth: Expert review.Gastroenterology. 2020;159:1526-1532. doi:10.1053/j.gastro.2020.06.090.Song Y, Liu Y, Qi B, et al.Association of small intestinal bacterial overgrowth with heart failure and its prediction for short-term outcomes.J Am Heart Assoc. 2021;10:e015292. doi: 10.1161/JAHA.119.015292.Additional ReadingKrajicek EJ, Hansel SL.Small intestinal bacterial overgrowth: A primary care review.Mayo Clin Proc.2016;91:1828-1833. doi:10.1016/j.mayocp.2016.07.025.Pimentel M, Saad RJ, Long MD, Rao SSC.ACG clinical guideline: small intestinal bacterial overgrowth.Am J Gastroenterol. 2020;115:165-178. doi:10.14309/ajg.0000000000000501.Rao SSC, Bhagatwala J.Small intestinal bacterial overgrowth: Clinical features and therapeutic management.Clin Transl Gastroenterol. 2019;10:e00078. doi:10.14309/ctg.0000000000000078.
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
Rezaie A, Pimentel M, Rao SS.How to test and treat small intestinal bacterial overgrowth: An evidence-based approach.Curr Gastroenterol Rep.2016;18:8. doi:10.1007/s11894-015-0482-9.Lasa JS, Zubiaurre I, Fanjul I, Olivera P, Soifer L.Small intestinal bacterial overgrowth prevalence in celiac disease patients is similar in healthy subjects and lower in irritable bowel syndrome patients.Rev Gastroenterol Mex. 2015;80:171-174. doi:10.1016/j.rgmx.2015.04.002.Shah A, Talley NJ, Jones M, et al.Small intestinal bacterial overgrowth in irritable bowel syndrome: A systematic review and Meta-analysis of case-control studies.Am J Gastroenterol. 2020;115:190-201. doi:10.14309/ajg.0000000000000504.Sachdev AH, Pimentel M.Gastrointestinal bacterial overgrowth: pathogenesis and clinical significance.Ther Adv Chronic Dis. 2013;4:223-231. doi:10.1177/2040622313496126.Quigley EMM, Murray JA, Pimentel M.AGA Clinical practice update on small intestinal bacterial overgrowth: Expert review.Gastroenterology. 2020;159:1526-1532. doi:10.1053/j.gastro.2020.06.090.Song Y, Liu Y, Qi B, et al.Association of small intestinal bacterial overgrowth with heart failure and its prediction for short-term outcomes.J Am Heart Assoc. 2021;10:e015292. doi: 10.1161/JAHA.119.015292.
Rezaie A, Pimentel M, Rao SS.How to test and treat small intestinal bacterial overgrowth: An evidence-based approach.Curr Gastroenterol Rep.2016;18:8. doi:10.1007/s11894-015-0482-9.
Lasa JS, Zubiaurre I, Fanjul I, Olivera P, Soifer L.Small intestinal bacterial overgrowth prevalence in celiac disease patients is similar in healthy subjects and lower in irritable bowel syndrome patients.Rev Gastroenterol Mex. 2015;80:171-174. doi:10.1016/j.rgmx.2015.04.002.
Shah A, Talley NJ, Jones M, et al.Small intestinal bacterial overgrowth in irritable bowel syndrome: A systematic review and Meta-analysis of case-control studies.Am J Gastroenterol. 2020;115:190-201. doi:10.14309/ajg.0000000000000504.
Sachdev AH, Pimentel M.Gastrointestinal bacterial overgrowth: pathogenesis and clinical significance.Ther Adv Chronic Dis. 2013;4:223-231. doi:10.1177/2040622313496126.
Quigley EMM, Murray JA, Pimentel M.AGA Clinical practice update on small intestinal bacterial overgrowth: Expert review.Gastroenterology. 2020;159:1526-1532. doi:10.1053/j.gastro.2020.06.090.
Song Y, Liu Y, Qi B, et al.Association of small intestinal bacterial overgrowth with heart failure and its prediction for short-term outcomes.J Am Heart Assoc. 2021;10:e015292. doi: 10.1161/JAHA.119.015292.
Krajicek EJ, Hansel SL.Small intestinal bacterial overgrowth: A primary care review.Mayo Clin Proc.2016;91:1828-1833. doi:10.1016/j.mayocp.2016.07.025.Pimentel M, Saad RJ, Long MD, Rao SSC.ACG clinical guideline: small intestinal bacterial overgrowth.Am J Gastroenterol. 2020;115:165-178. doi:10.14309/ajg.0000000000000501.Rao SSC, Bhagatwala J.Small intestinal bacterial overgrowth: Clinical features and therapeutic management.Clin Transl Gastroenterol. 2019;10:e00078. doi:10.14309/ctg.0000000000000078.
Krajicek EJ, Hansel SL.Small intestinal bacterial overgrowth: A primary care review.Mayo Clin Proc.2016;91:1828-1833. doi:10.1016/j.mayocp.2016.07.025.
Pimentel M, Saad RJ, Long MD, Rao SSC.ACG clinical guideline: small intestinal bacterial overgrowth.Am J Gastroenterol. 2020;115:165-178. doi:10.14309/ajg.0000000000000501.
Rao SSC, Bhagatwala J.Small intestinal bacterial overgrowth: Clinical features and therapeutic management.Clin Transl Gastroenterol. 2019;10:e00078. doi:10.14309/ctg.0000000000000078.
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