SIBO Management Guidelines
Diagnostic Approach
Testing rather than empirical treatment should be used whenever possible to establish SIBO diagnosis, prioritizing combined hydrogen-methane breath testing as the first-line diagnostic method. 1
Preferred Diagnostic Testing
- Combined hydrogen and methane breath testing is more effective at identifying SIBO than hydrogen testing alone, as it detects both hydrogen-producing bacteria and methane-producing archaea 1
- Glucose or lactulose breath tests are helpful, though not always accurate; when clearly positive, they point to the presence of SIBO 1
- Qualitative small bowel aspiration is much easier to carry out than quantitative assessment and can help make the diagnosis 1
When to Perform Small Bowel Aspiration
- Flush 100 mL of sterile saline into the duodenum, flush channel with 10 mL of air, turn down suction, leave fluid for a few seconds, then aspirate ≥10 mL into a sterile trap 1
- Positive aspirates will grow colonic bacteria 1
- Agreement on appropriate processing and reporting of samples by local microbiology services should be obtained before undertaking qualitative assessment 1
Key Diagnostic Pitfall
- Lack of response to empirical antibiotics may be due to resistant organisms, SIBO not being present, or because other disorders causing similar symptoms are also present 1
- This is particularly problematic in patient groups where multiple diagnoses often coincide 1
Treatment Guidelines
First-Line Antibiotic Therapy
Rifaximin 550 mg twice daily for 1-2 weeks is the most investigated and preferred treatment, effective in approximately 60-80% of patients with proven SIBO. 1
Alternative Antibiotic Options
- Other equally effective antibiotics include doxycycline, ciprofloxacin, amoxicillin-clavulanic acid, and cefoxitin 1
- Metronidazole is less effective and should not be first-line 1
- Antibiotics which are not absorbed from the GI tract (like rifaximin) are preferable to absorbed antibiotics to reduce the risk of systemic resistance 1
Duration and Recurrence Management
- In patients with reversible cause for SIBO (e.g., immunosuppression during chemotherapy), usually one course of antibiotics is all that is required 1
- In patients with recurrent SIBO, approaches include low-dose long-term antibiotics, cyclical antibiotics, or recurrent short courses of antibiotics 1
Identifying Underlying Causes
Common Predisposing Factors to Address
- Proton pump inhibitors reduce the gastric acid barrier and should be discontinued if possible 2
- Medications affecting motility (vincristina, anticolinérgicos, clozapina) should be reviewed 2
- Diabetes with autonomic neuropathy impairs the migrating motor complex (MMC) 2
- Anatomical abnormalities including resection of ileocecal valve, surgical blind loops, or fistulae 2
- Pancreatic exocrine insufficiency reduces bacteriostatic pancreatic secretions 2
Critical Clinical Context
- The etiología of SIBO is often multifactorial, with more than one mechanism involved 2
- In patients with severe chronic intestinal dysmotility, SIBO is practically inevitable and can cause cachexia even without evident diarrhea 2
- SIBO can complicate up to 92% of cases of chronic pancreatitis with pancreatic exocrine insufficiency 2
Important Caveats
When Elevated Inflammatory Markers Are Present
- SIBO does not cause elevated fecal calprotectin; elevated levels should prompt investigation for alternative causes of inflammation such as inflammatory bowel disease 3
- SIBO and elevated inflammatory markers should be treated as separate conditions requiring distinct therapeutic approaches 3
- Antibiotics for SIBO and anti-inflammatory therapy for the inflammatory process should be administered separately 3