IRRITABLE BOWEL SYNDROME (IBS)

Post Infectious IBS: Road to Cure – Dr. Mark Pimental

Dr. Mark Pimentel explained that IBS is now understood as a real, physical illness—often starting after food poisoning—rather than something “in the mind.” Certain bacteria from contaminated food make a toxin that can trigger the immune system to mistakenly attack nerves in the gut. This damage stops the gut’s natural “cleaning waves,” leading to a buildup of bacteria in the small intestine (SIBO). Around 60% of IBS cases are linked to this process. There are three main SIBO types—hydrogen, hydrogen sulfide, and methane—which cause different symptoms like diarrhea or constipation and need different treatments. New blood tests can confirm post-infectious IBS, proving it’s a true disease and helping doctors create more targeted treatments.

Irritable Bowel Syndrome and the Gut Microbiome: A Comprehensive Review (J Clin Med, 2022)
This is a broad, up-to-date review that pulls together human and animal studies to show how alterations in the gut microbiome are a consistent feature of many people with IBS. The authors review evidence linking microbial shifts to hallmark IBS mechanisms — changes in motility, visceral hypersensitivity, low-grade immune activation, altered fermentation and gas production, and changes to the gut–brain axis. They also summarize clinical approaches that target the microbiome (low-FODMAP diet, rifaximin, specific probiotics, and FMT), noting the strongest evidence is for dietary manipulation and rifaximin in selected subgroups. Importantly, the review emphasizes heterogeneity: not all IBS patients show the same microbial patterns, and study methods differ widely, so translating microbiome findings to routine care still needs standardized tests and better predictive markers.

Is Irritable Bowel Syndrome a Diagnosis of Exclusion?: A Survey of Primary Care Providers, Gastroenterologists, and IBS Experts

This study found that while IBS should be diagnosed based on symptoms (using tools like the Rome criteria), most general healthcare providers still treat it as a diagnosis of exclusion—meaning they only diagnose IBS after ruling out other conditions. In contrast, IBS specialists are more likely to make a direct diagnosis based on symptoms alone, order fewer tests, and spend less on investigations. The findings highlight a gap between expert guidelines and everyday practice, suggesting the need for better education and guideline use among non-specialists.

Predicting Response to Rifaximin in Irritable Bowel Syndrome with Diarrhea: Is the Answer Blowing in the Wind?

This study found that a simple breath test (called lactulose breath test) can help predict if people with IBS and diarrhea will feel better after taking the antibiotic rifaximin. People with a positive breath test were more likely to improve, but the chance of symptoms coming back later was similar for everyone. This means the test can help decide who might benefit most from the treatment.