Small intestinal bacterial overgrowth: Clinical manifestations and diagnosis
- Mark Pimentel, MD, FRCP(C)
Mark Pimentel, MD, FRCP(C)
- Executive Director
- Medically Associated Science and Technology (MAST) Program
- Cedars-Sinai Medical Center
Small intestinal bacterial overgrowth (SIBO) is a condition in which the small bowel is colonized by excessive aerobic and anaerobic microbes that are normally present in the colon.
This topic will review the etiology, pathogenesis, clinical manifestations, and diagnosis of SIBO. The management of SIBO is discussed in detail, separately. (See "Small intestinal bacterial overgrowth: Etiology and pathogenesis" and "Small intestinal bacterial overgrowth: Management".)
The population-based prevalence of SIBO is unclear. The incidence of SIBO increases with age.
ETIOLOGY AND RISK FACTORS
Several disorders predispose to SIBO by altering mucosal defenses (table 1). Intestinal motility disorders and chronic pancreatitis are estimated to account for approximately 90 percent of cases of SIBO [1-3]. Patients may have more than one predisposing cause. As an example, the high prevalence of SIBO in older adults may be due to small intestinal dysmotility and gastric hypochlorhydria.
●Motility disorders — The migrating motor complex (MMC) and in particular, phase III of the MMC clears the small bowel of debris . A lack of interdigestive phase III activity in patients with irritable bowel syndrome, narcotic use, intestinal pseudo-obstruction, and diabetes predisposes them to SIBO. Small bowel motility is also affected in acute or chronic radiation enteritis, amyloidosis, and scleroderma [5-9]. (See "Pathophysiology of irritable bowel syndrome", section on 'Bacterial overgrowth' and "Gastrointestinal manifestations of systemic sclerosis (scleroderma)", section on 'Small intestinal involvement'.)To continue reading this article, you must log in with your personal, hospital, or group practice subscription. For more information on subscription options, click below on the option that best describes you:
- Mackie RI, Sghir A, Gaskins HR. Developmental microbial ecology of the neonatal gastrointestinal tract. Am J Clin Nutr 1999; 69:1035S.
- Choung RS, Ruff KC, Malhotra A, et al. Clinical predictors of small intestinal bacterial overgrowth by duodenal aspirate culture. Aliment Pharmacol Ther 2011; 33:1059.
- Pimentel M. Evaluating a bacterial hypothesis in IBS using a modification of Koch's postulates: part 1. Am J Gastroenterol 2010; 105:718.
- Vantrappen G, Janssens J, Hellemans J, Ghoos Y. The interdigestive motor complex of normal subjects and patients with bacterial overgrowth of the small intestine. J Clin Invest 1977; 59:1158.
- Shah ED, Basseri RJ, Chong K, Pimentel M. Abnormal breath testing in IBS: a meta-analysis. Dig Dis Sci 2010; 55:2441.
- Posserud I, Stotzer PO, Björnsson ES, et al. Small intestinal bacterial overgrowth in patients with irritable bowel syndrome. Gut 2007; 56:802.
- Pyleris E, Giamarellos-Bourboulis EJ, Tzivras D, et al. 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.
- Kim G, Morales W, Funari V, et al. Duodenal Aeromonas SPP Are Increased in Number in a Rat Model of Post-Infectious IBS: Translation of Data From Deep Sequencing of the Microbiome in Humans With IBS. Gastroenterology 2013; 144:S542.
- Giamarellos-Bourboulis E, Tang J, Pyleris E, et al. Molecular assessment of differences in the duodenal microbiome in subjects with irritable bowel syndrome. Scand J Gastroenterol 2015; 50:1076.
- Bures J, Cyrany J, Kohoutova D, et al. Small intestinal bacterial overgrowth syndrome. World J Gastroenterol 2010; 16:2978.
- Jones RM, Neish AS. Recognition of bacterial pathogens and mucosal immunity. Cell Microbiol 2011; 13:670.
- Bouhnik Y, Alain S, Attar A, et al. Bacterial populations contaminating the upper gut in patients with small intestinal bacterial overgrowth syndrome. Am J Gastroenterol 1999; 94:1327.
- Kirsch M. Bacterial overgrowth. Am J Gastroenterol 1990; 85:231.
- Justus PG, Fernandez A, Martin JL, et al. Altered myoelectric activity in the experimental blind loop syndrome. J Clin Invest 1983; 72:1064.
- Pai RK. A practical approach to small bowel biopsy interpretation: celiac disease and its mimics. Semin Diagn Pathol 2014; 31:124.
- Shindo K, Machida M, Koide K, et al. Deconjugation ability of bacteria isolated from the jejunal fluid of patients with progressive systemic sclerosis and its gastric pH. Hepatogastroenterology 1998; 45:1643.
- Donaldson RM Jr. Role of enteric microorganisms in malabsorption. Fed Proc 1967; 26:1426.
- Sherman P, Lichtman S. Small bowel bacterial overgrowth syndrome. Dig Dis 1987; 5:157.
- Su J, Smith MB, Rerknimitr R, Morrow D. Small intestine bacterial overgrowth presenting as protein-losing enteropathy. Dig Dis Sci 1998; 43:679.
- Bongaerts GP, Tolboom JJ, Naber AH, et al. Role of bacteria in the pathogenesis of short bowel syndrome-associated D-lactic acidemia. Microb Pathog 1997; 22:285.
- Quigley EM, Abu-Shanab A. Small intestinal bacterial overgrowth. Infect Dis Clin North Am 2010; 24:943.
- de Boissieu D, Chaussain M, Badoual J, et al. Small-bowel bacterial overgrowth in children with chronic diarrhea, abdominal pain, or both. J Pediatr 1996; 128:203.
- Collins BS, Lin HC. Chronic abdominal pain in children is associated with high prevalence of abnormal microbial fermentation. Dig Dis Sci 2010; 55:124.
- Taylor SF, Sondheimer JM, Sokol RJ, et al. Noninfectious colitis associated with short gut syndrome in infants. J Pediatr 1991; 119:24.
- Tabaqchali S, Pallis C. Reversible nicotinamide-deficiency encephalopathy in a patient with jejunal diverticulosis. Gut 1970; 11:1024.
- Giannella RA, Toskes PP. Gastrointestinal bleeding and iron absorption in the experimental blind loop syndrome. Am J Clin Nutr 1976; 29:754.
- Klaus J, Spaniol U, Adler G, et al. Small intestinal bacterial overgrowth mimicking acute flare as a pitfall in patients with Crohn's Disease. BMC Gastroenterol 2009; 9:61.
- Lappinga PJ, Abraham SC, Murray JA, et al. Small intestinal bacterial overgrowth: histopathologic features and clinical correlates in an underrecognized entity. Arch Pathol Lab Med 2010; 134:264.
- Rezaie A, Buresi M, Lembo A, et al. Hydrogen and Methane-Based Breath Testing in Gastrointestinal Disorders: The North American Consensus. Am J Gastroenterol 2017; 112:775.
- Riordan SM, McIver CJ, Walker BM, et al. The lactulose breath hydrogen test and small intestinal bacterial overgrowth. Am J Gastroenterol 1996; 91:1795.
- Romagnuolo J, Schiller D, Bailey RJ. Using breath tests wisely in a gastroenterology practice: an evidence-based review of indications and pitfalls in interpretation. Am J Gastroenterol 2002; 97:1113.
- Khoshini R, Dai SC, Lezcano S, Pimentel M. A systematic review of diagnostic tests for small intestinal bacterial overgrowth. Dig Dis Sci 2008; 53:1443.
- Ghoshal UC, Ghoshal U, Das K, Misra A. Utility of hydrogen breath tests in diagnosis of small intestinal bacterial overgrowth in malabsorption syndrome and its relationship with oro-cecal transit time. Indian J Gastroenterol 2006; 25:6.
- Corazza GR, Menozzi MG, Strocchi A, et al. The diagnosis of small bowel bacterial overgrowth. Reliability of jejunal culture and inadequacy of breath hydrogen testing. Gastroenterology 1990; 98:302.
- King CE, Toskes PP. Comparison of the 1-gram [14C]xylose, 10-gram lactulose-H2, and 80-gram glucose-H2 breath tests in patients with small intestine bacterial overgrowth. Gastroenterology 1986; 91:1447.
- Stotzer PO, Kilander AF. Comparison of the 1-gram (14)C-D-xylose breath test and the 50-gram hydrogen glucose breath test for diagnosis of small intestinal bacterial overgrowth. Digestion 2000; 61:165.
- Kerlin P, Wong L. Breath hydrogen testing in bacterial overgrowth of the small intestine. Gastroenterology 1988; 95:982.
- Mac Mahon M, Gibbons N, Mullins E, et al. Are hydrogen breath tests valid in the elderly? Gerontology 1996; 42:40.
- Rana SV, Sharma S, Kaur J, et al. Comparison of lactulose and glucose breath test for diagnosis of small intestinal bacterial overgrowth in patients with irritable bowel syndrome. Digestion 2012; 85:243.
- Bardhan PK, Gyr K, Beglinger C, et al. Diagnosis of bacterial overgrowth after culturing proximal small-bowel aspirate obtained during routine upper gastrointestinal endoscopy. Scand J Gastroenterol 1992; 27:253.
- Shanab AA, Quera RM, Quigley EMM. Small intestinal bacterial overgrowth. In: Textbook of Clinical Gastroenterology and Hepatology, 2nd ed, Hawkey CJ, Bosch J, Richter JE, et al (Eds), Wiley-Blackwell, Malden, MA 2012.
- Fan X, Sellin JH. Review article: Small intestinal bacterial overgrowth, bile acid malabsorption and gluten intolerance as possible causes of chronic watery diarrhoea. Aliment Pharmacol Ther 2009; 29:1069.
- Ratuapli SK, Ellington TG, O'Neill MT, et al. Proton pump inhibitor therapy use does not predispose to small intestinal bacterial overgrowth. Am J Gastroenterol 2012; 107:730.
- ETIOLOGY AND RISK FACTORS
- CLINICAL FEATURES
- Clinical presentation
- Laboratory findings
- Endoscopy findings
- Approach to evaluation
- Carbohydrate breath test
- Jejunal aspirate culture
- DIFFERENTIAL DIAGNOSIS
- EVALUATION TO DETERMINE THE ETIOLOGY
- SUMMARY AND RECOMMENDATIONS