Small Intestinal Bacterial Overgrowth

  • Konstantinos Triantafyllou
  • Mark Pimentel


Soon after birth, the previously sterile infant gastrointestinal tract becomes colonized by microbes. Because of the bactericidal action of gastric acid and the sweeping of the intestinal lumen by peristalsis, the proximal small intestine is normally colonized by a relatively small number of bacteria, consisting mainly of Gram-positive microbes and anaerobes from the oral cavity. In the ileum, an increase in microbial colonization of up to 109 colony-forming units (CFU)/mL occurs, due mainly to Gram-negative microbes and anaerobes. Finally, the colon contains an abundance of mostly anaerobic microbes at a concentration of up to 1012 CFU/mL.


Irritable Bowel Syndrome Celiac Disease Breath Test Small Intestinal Bacterial Overgrowth Proximal Small Intestine 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Key References

  1. 1.
    DiBaise JK. Nutritional consequences of small intestinal bacterial overgrowth. Pract Gastroenterol. 2008;69:15–29. Review of the nutritional aspects of SIBO including treatment recommendations.Google Scholar
  2. 2.
    Khoshini R, Dai S-C, Lezcano S, Pimentel M. A systematic review of diagnostic tests for small intestinal bacterial overgrowth. Dig Dis Sci. 2008;53:1443–54. Systematic review that questions the validity of available tests used to diagnose SIBO.PubMedCrossRefGoogle Scholar
  3. 3.
    Pyleris M, Giamarellos-Bourboulis EJ, Tsivras D, Koussoulas V, Barbatzas C, Pimentel M. The prevalence of overgrowth by aerobic bacteria in the small intestine by small bowel culture: relationship with irritable bowel syndrome. Dig Dis Sci. 2012;57:1321–9. The strongest evidence to date linking SIBO with IBS using aspirate.PubMedCrossRefGoogle Scholar
  4. 4.
    Quigley EMM, Abu-Shanab A. Small intestinal bacterial overgrowth. Infect Dis Clin N Am. 2010;24:943–59. Review of the clinical, diagnostic and treatment aspects of small bowel bacterial overgrowth.CrossRefGoogle Scholar
  5. 5.
    Simren M, Barbara G, Flint HJ, Spiegel BMR, Spiller RC, Vanner S, Verdu EF, Whorwell PJ, Zoetendal EG. Intestinal microbiota in functional bowel disorders: A Rome foundation report. Gut. 2013;62:159–76. Extensive discussion of the association of gut microbiota and functional bowel diseases.PubMedCrossRefPubMedCentralGoogle Scholar
  6. 6.
    Yamini D, Pimentel M. Irritable bowel syndrome and small intestinal bacterial overgrowth. J Clin Gastroenterol. 2010;44:672–5. Comprehensive summary of the available evidence that links SIBO to IBS.PubMedCrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media New York 2015

Authors and Affiliations

  1. 1.Hepatogastroenterology Unit, Second Department of Internal Medicine and Research InstituteAttikon University General HospitalHaidariGreece
  2. 2.GI Motility Program, Division of GastroenterologyCedars-Sinai Medical CenterLos AngelesUSA

Personalised recommendations