Overgrown bacteria is unresponsive

Dear Dr. Roach: I have been suffering with small intestine bacterial overgrowth syndrome for five years. It started when I was treated for H. pylori with omeprazole. I’ve had two endoscopies, a colonoscopy and lab tests. I’m negative for celiac disease. I had a positive breath test four years ago. I’ve taken five courses of antibiotics, including rifaximin and neomycin with brief relief each time. I have well-controlled diabetes. — D.D.

Small intestine bacterial overgrowth syndrome is when there are more bacteria in the small intestine than normal. The major symptoms are bloating, gas, abdominal discomfort and diarrhea. It can be complicated by weight loss and vitamin deficiencies. The diagnosis is made by a breath test, and this ideally looks at both methane and hydrogen in the breath after consuming a test meal of sugar. In hydrogenpredominant SIBO, rifaximin for two weeks usually is effective; however, in methane-predominant SIBO, a combination of rifaximin and neomycin will be more effective. In people who fail appropriate antibiotics, many experts recommend an “elemental” diet, which is expensive and not particularly appetizing, for up to three weeks. This diet contains the nutrients, such as amino acids and sugars, already broken down, allowing for faster transit time. That is an effective treatment for some people with irritable bowel syndrome, even if it didn’t work for you. Medication to improve how fast the small intestine squeezes may be helpful, especially in someone with diabetes. Erythromycin is one choice. Its effect of speeding up the gut is more important than its antibiotic effects. If all of these fail, it’s time to re-evaluate whether the diagnosis was correct (another breath test is probably appropriate), and think about alternative possibilities for the symptoms.