Dysmotility and proton pump inhibitor use are independent risk factors for small intestinal bacterial and/or fungal overgrowth

Aliment Pharmacol Ther. 2013 Jun;37(11):1103-11. doi: 10.1111/apt.12304. Epub 2013 Apr 10.


Background: Whether intestinal dysmotility and the use of a proton pump inhibitor (PPI) either independently or together contributes to small intestinal bacterial overgrowth (SIBO), and/or small intestinal fungal overgrowth (SIFO) is not known.

Aim: To investigate the role of dysmotility and PPI use in patients with persistent gastrointestinal complaints.

Methods: Patients with unexplained gastrointestinal symptoms and negative endoscopy/radiology tests completed a validated symptom questionnaire and underwent 24-h ambulatory antro-duodeno-jejunal manometry (ADJM). Simultaneously, duodenal aspirate was obtained for aerobic, anaerobic and fungal culture. Dysmotility was diagnosed by (>2): absent phase III MMC, absent/diminished postprandial response, diminished amplitude of antral/intestinal phasic activity, impaired antro-duodenal coordination. Bacterial growth ≥10³ CFU/mL or fungal growth was considered evidence for SIBO/SIFO. PPI use was documented. Correlation of symptoms with presence of SIBO or SIFO was assessed.

Results: One hundred and fifty subjects (M/F = 47/103) were evaluated; 94/150 (63%) had overgrowth: 38/94 (40%) had SIBO, 24/94 (26%) had SIFO and 32/94 (34%) had mixed SIBO/SIFO. SIBO was predominately due to Streptococcus, Enterococcus, Klebsiella and E. coli. SIFO was due to Candida. Eighty of 150 (53%) patients had dysmotility and 65/150 (43%) used PPI. PPI use (P = 0.0063) and dysmotility (P = 0.0003) were independent significant risk factors (P < 0.05) for overgrowth, but together did not pose additional risk. Symptom profiles were similar between those with or without SIBO/SIFO.

Conclusions: Dysmotility and PPI use were independent risk factors for SIBO or SIFO and were present in over 50% of subjects with unexplained gastrointestinal symptoms. Diagnosis of overgrowth requires testing because symptoms were poor predictors of overgrowth.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Bacteria / isolation & purification
  • Bacterial Infections / microbiology*
  • Colony-Forming Units Assay
  • Enteritis / microbiology*
  • Female
  • Fungi / isolation & purification
  • Gastrointestinal Diseases / complications*
  • Gastrointestinal Motility*
  • Humans
  • Intestine, Small / microbiology*
  • Male
  • Middle Aged
  • Mycoses / microbiology*
  • Proton Pump Inhibitors / adverse effects*
  • Risk Factors
  • Young Adult


  • Proton Pump Inhibitors