Small intestinal bacterial and fungal overgrowth

Jigar Bhagatwala, Satish S.C. Rao

Research output: Chapter in Book/Report/Conference proceedingChapter

1 Scopus citations


Millions of patients in the United States and across the world suffer from unexplained yet common gastrointestinal symptoms such as abdominal pain, bloating, gas, indigestion, diarrhea and nausea. An underrecognized cause of these symptoms is small intestinal bacterial and/or fungal overgrowth. These conditions are not only common but their prevalence is rising. Several conditions and risk factors have been identified, in particular altered gut anatomy such as Intestinal by pass surgery and colectomy, drugs such as proton pump inhibitors and opioids, intestinal dysmotility from scleroderma or pseudo-obstruction syndromes and many others. Upper endoscopy with small bowel aspirates and culture remains the “gold-standard” test for diagnosing bacterial and fungal overgrowth, but is invasive. Breath hydrogen and methane tests, particularly using glucose as a substrate has good specificity but low sensitivity and requires further validation. Anti-microbial agents remain the mainstay of therapy and can have a tremendous impact on patients’ symptoms. Rifaximin, amoxicillin, levofloxacin, metronidazole, trimethoprim/sulfamethoxazole and tetracycline have been demonstrated to be useful for SIBO. Fluconazole and nystatin can be useful for SIFO. More research is needed regarding standardizing non-invasive diagnostic criteria. Also large sample size, rigorously controlled, randomized treatment trials for both SIBO and SIFO are needed in order to recommend effective therapeutic algorithms.

Original languageEnglish (US)
Title of host publicationClinical and Basic Neurogastroenterology and Motility
Number of pages16
ISBN (Electronic)9780128130377
ISBN (Print)9780128130384
StatePublished - Jan 1 2019


  • Antibiotics
  • Antifungals
  • Diagnosis
  • Duodenal aspirates/culture
  • Glucose breath tests
  • Small intestinal bacterial overgrowth
  • Small intestinal fungal overgrowth

ASJC Scopus subject areas

  • Medicine(all)


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