Small Bowel Bacterial Overgrowth

(SBBO; Bacterial Overgrowth, Small Bowel; Small Intestine Bacterial Overgrowth; SIBO; Bacterial Overgrowth, Small Intestine)

Definition

Small bowel bacterial overgrowth (SBBO) occurs when there is a build-up of too much bacteria in the small bowel.

The Small Intestines
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Causes  ^

SBBO is often caused by an abnormality in the small bowel. Food is not able to flow properly though the intestines. Conditions that may cause this include:

  • Birth defect
  • Injury
  • Surgery
  • Digestive disorders

Risk Factors  ^

Factors that may increase your chance of SBBO include:

Other risk factors include:

  • Intestinal surgery
  • An obstruction in the small intestine
  • Weakened immune system
  • Older age

Any condition that affects how food moves through the small bowel may increase the risk of SBBO.

Symptoms  ^

SBBO may cause:

Diagnosis  ^

Your doctor will ask about your symptoms and medical history. A physical exam will be done.

Tests may include

  • Blood tests
  • Breath tests—to analyze certain gases that may be present after fasting and eating specific sugars
  • Culture of intestinal fluid (aspirate)—a catheter is used to get a sample of fluid from the small bowel

Treatment  ^

The goals are to:

  • Reduce the levels of harmful bacteria in the small bowel
  • Treat the underlying condition

Medications

Antibiotics are often prescribed to treat SBBO. Usually treatment is temporary, but in some cases you may need to take antibiotics for a longer period.

Nutritional Support

To make sure that you get the proper nutrients, you may need to:

  • Work with a dietitian
  • Follow a special diet, such as a carbohydrate-restricted diet
  • Take vitamins and/or supplements
  • Take probiotics

In some cases, tube feeding is needed with a special formula.

Surgery

For severe cases, surgery may be needed. This is done to correct an abnormality in the small bowel.

Prevention  ^

If you have any of the conditions that are linked to SBBO, get proper treatment. This may reduce your chance of having a build-up of bacteria in the small bowel.

RESOURCES:

American Gastroenterological Association
http://www.gastro.org

National Institute of Diabetes and Digestive and Kidney Diseases
http://www.niddk.nih.gov

CANADIAN RESOURCES:

Canadian Association of Gastroenterology
http://www.cag-acg.org

Canadian Digestive Health Foundation
http://www.cdhf.ca

REFERENCES:

Bacterial overgrowth syndrome. Merck Manual Professional Version website. Available at: http://www.merckmanuals.com/professional/gastrointestinal-disorders/malabsorption-syndromes/bacterial-overgrowth-syndrome. Updated May 2014. Accessed September 29, 2014.

Bures J, Cyrany J, Kohoutova D, et al. Small intestinal bacterial overgrowth syndrome. World J Gastroenterol. 2010;16(24):2978–2990.

Lactose and glucose hydrogen breath test. Cleveland Clinic website. Available at: http://my.clevelandclinic.org/health/diagnostics/hic_Lactose_and_Glucose_Hydrogen_Breath_Test. Accessed September 29, 2014.

Lin H. Small intestinal bacterial overgrowth. JAMA. 2004;292(7):852-858.

Parrish C. Nutritional consequences of small intestinal bacterial overgrowth. University of Virginia, School of Medicine website. Available at: http://www.medicine.virginia.edu/clinical/departments/medicine/divisions/digestive-health/nutrition-support-team/nutrition-articles/DiBaiseArticle.pdf. Accessed September 29, 2014.

Short bowel syndrome. EBSCO DynaMed Plus website. Available at:http://www.dynamed.com/topics/dmp~AN~T115699/Short-bowel-syndrome. Updated May 6, 2014. Accessed September 29, 2014.

Vanderhoof J, Young R. Bacterial overgrowth. The Oley Foundation website. Available at: http://www.oley.org/lifeline/bacter.html. Accessed September 29, 2014.

Vanderhoof J, Young R, Murray N, Kaufman SS. Treatment strategies for small bowel bacterial overgrowth in short bowel syndrome. J Pediatr Gastroenterol Nutr. 1998;27(2):155-160.

Last reviewed August 2015 by Daus Mahnke, MD  Last Updated: 9/30/2013