Non-absorbable antibiotics and small bowel bacterial overgrowth

Area of Science:

• Gastroenterology
• Microbiology
• Internal Medicine

Background:

• Normal gastrointestinal flora is characterized by low microbial concentrations, primarily gram-positive aerobic bacteria.
• Abnormal small bowel bacterial overgrowth (SBBO) involves increased microbial concentrations (> or = 10(7)/ml) with a predominance of anaerobes and coliforms.
• SBBO can lead to malabsorption syndromes, presenting with symptoms like diarrhea, weight loss, and megaloblastic anemia.

Purpose of the Study:

• To review the diagnostic challenges and therapeutic strategies for small intestinal bacterial overgrowth.
• To highlight the efficacy of rifaximin in treating SBBO and related gastrointestinal disorders.

Main Methods:

• Bacteriological analysis of jejunal aspirate is the gold standard for diagnosing SBBO but is invasive.
• Non-invasive alternatives like glucose or lactulose hydrogen breath tests have been developed.
• Antimicrobial therapy, particularly with non-absorbable antibiotics, is the primary treatment approach.

Main Results:

• Rifaximin, a locally acting non-absorbable antibiotic, exhibits bactericidal activity against both aerobic and anaerobic bacteria implicated in SBBO.
• Clinical trials demonstrate rifaximin's therapeutic efficacy in conditions including bacterial diarrhea, hepatic encephalopathy, diverticulosis, and SBBO.
• Rifaximin offers a targeted approach to suppressing bacterial colonization in the small intestine.

Conclusions:

• Accurate diagnosis of SBBO is crucial, with non-invasive breath tests offering a practical alternative to jejunal aspiration.
• Rifaximin is a valuable therapeutic option for managing SBBO due to its broad-spectrum activity and local action.
• Effective treatment of SBBO can alleviate malabsorption symptoms and improve patient outcomes.