Key Takeaways:
- Biofilms were found in over half of IBS patients, suggesting a possible role in symptoms.
- Antibiotics alone may not work—IBS likely involves multiple causes like dysbiosis and stress.
- Managing diet, especially with a low-FODMAP approach, remains one of the best ways to reduce flare-ups.
Irritable bowel syndrome (IBS) affects an estimated 5% of the adult population and is one of the most common yet poorly understood gastrointestinal disorders. Characterized by abdominal pain, bloating, diarrhea, and constipation, IBS is often diagnosed only after other conditions are ruled out. Many patients face years of misdiagnosis, and symptoms often emerge between the ages of 30 and 40. Women are more frequently affected than men, with a 3:1 ratio.
Now, a major study may be shifting that understanding. In a large multicenter investigation published in Gastroenterology, Austrian researchers performed 1,426 colonoscopies and discovered that about 57% of IBS patients had bacterial biofilms coating their intestinal lining, compared to just 6% of healthy controls. These sticky, yellow-green layers weren’t just debris—they were structured bacterial communities possibly tied to persistent symptoms.
So, what exactly did the researchers observe—and why does it matter for IBS treatment?
Intestinal Microbiota
What Did the Study Find?
In this multicenter study, Austrian researchers performed over 1,400 colonoscopies across two major hospitals and found that about two-thirds of IBS patients had mucosal biofilms in the small or large intestine. In contrast, only one-third of patients with ulcerative colitis and just 6% of healthy individuals had similar biofilms.
“Until now, studies have always assumed that this sticky film was formed by residues of impurities in the gut that were difficult to remove,” explains Dr. Christoph Gasche, head of the Laboratory of Molecular Gastroenterology at the Medical University of Vienna. “However, we have now been able to show that this is where the bacterial matrix adheres.”
These biofilms appeared as yellow-green layers and were typically located in areas where symptoms were reported. The discovery opens the door to possible new treatment options, particularly since, in some cases, doctors were able to flush the biofilms from the colon during endoscopy—although removing them from the small intestine remains more challenging.
How Biofilms May Form
The researchers also explored what might cause these biofilms to develop in the first place. One major factor appeared to be long-term medication use. Patients who had taken many drugs over the course of their lives—especially those who had undergone organ transplants—showed higher rates of biofilm formation.
“Some drugs, such as proton pump inhibitors, can disrupt the balance of the bacterial ecosystem,” says Dr. Gasche. “The bacteria then go into survival mode. To have a better chance of surviving this stress, they clump together for safety and form biofilms—a kind of protective space that makes them resistant to antibiotics and other environmental toxins.”
This new insight may explain why antibiotics have limited effectiveness in many IBS cases. Biofilms may protect bacteria from both treatment and immune responses, making them harder to eradicate through conventional therapies.
Related Reading:
IBS: How to Treat the Diarrhea, Bloating, Flatulence and Abdominal Pain
IBS and Other Inflammatory Bowel Conditions Possibly Related to Mucus Production
Gilmore Health: A Q&A Session on IBS With Dr. Sony Sherpa
IBS Breakthrough: Eliminating the Bacteria Brachyspira May Treat Irritable Bowel Syndrome
Unanswered Questions and Cautionary Notes
Although these findings are promising, several questions remain. For instance, if bacterial biofilms are so common in IBS patients, why haven’t antibiotic treatments—often used for related issues like SIBO—led to consistent improvement? It’s possible that biofilms act as a defense mechanism for bacteria, making them more resistant to antibiotics. But they could also be a byproduct of dysbiosis rather than the root cause.
The fact that only around 57% of IBS patients in the study had detectable biofilms suggests that this may not be a universal explanation. And some individuals with biofilms may never develop symptoms, raising the possibility that other factors—like inflammation, nerve sensitivity, or stress—may influence how IBS manifests.
For patients, this means treatments targeting biofilms may not be a magic bullet. More research is needed to determine who will benefit and how these findings integrate into long-term management plans.
FAQs
What did the study show?
Researchers found gut biofilms in 57% of IBS patients and just 6% of healthy controls.
How many patients were studied?
Over 1,400 colonoscopies were done across two centers.
Where were the biofilms located?
Mostly in the small intestine, also in the colon.
How were the biofilms identified?
Via endoscopy, microscopy, DNA sequencing, and bile acid testing.
Do biofilms cause IBS?
Not confirmed. They may contribute but aren’t the sole cause.
Why do antibiotics often fail in IBS?
Biofilms shield bacteria from antibiotics. IBS also has multiple causes.
Does everyone with IBS have biofilms?
No—about 43% didn’t. And some people with biofilms have no symptoms.
What is dysbiosis and how does it relate?
It’s an imbalance of gut bacteria. Biofilms may be a symptom of it.
Can current treatments remove biofilms?
Colon irrigation can sometimes help. Small intestine biofilms are harder to reach.
Is testing for biofilms available?
Not routinely. It requires colonoscopy and lab analysis.
What current treatments work best?
Low-FODMAP diet, trigger tracking, probiotics, stress reduction, meds for pain or bowel changes.
Are antibiotics still used?
Yes—like rifaximin for SIBO—but results vary and relapse is common.
Are biofilm-specific treatments available now?
No, but enzyme and probiotic approaches are under study.
Should I ask my doctor about biofilms?
Yes, especially if you have persistent symptoms. But expect cautious responses.
What’s next in IBS research?
Targeted microbiome therapies, anti-biofilm drugs, and better diagnostic tools.
What can I do now to feel better?
Avoid known food triggers, try a low-FODMAP diet, manage stress, and stay informed.
Final Thoughts
This study gives us one more piece of the IBS puzzle—but it doesn’t solve it outright. Biofilms might explain symptoms for some, but not all. And even when they are present, they may not be the sole reason a person develops IBS. That’s why treatments like antibiotics haven’t worked consistently—because IBS probably isn’t caused by one thing.
If you’re living with IBS, the takeaway isn’t to chase a single solution, but to stay curious and involved in your care. Ask your doctor about new research, but also focus on what’s already known to help. That includes managing what you eat—many people find relief by following a low-FODMAP diet or avoiding specific trigger foods. Keep a food journal if you’re unsure what affects you.
Also, don’t overlook the basics: get enough sleep, move your body regularly, and find ways to manage stress. IBS may be complicated, but that doesn’t mean you’re stuck.
There’s no one-size-fits-all fix. But with studies like this pushing the science forward, there’s reason to be hopeful.
References
Baumgartner, M., Lang, M., Holley, H., Makristathis, A., Muttenthaler, M., & Gasche, C. (2021). Mucosal Biofilms Are an Endoscopic Feature of Irritable Bowel Syndrome and Ulcerative Colitis. Gastroenterology, 161(4), 1245-1256.e20. https://doi.org/10.1053/j.gastro.2021.06.024
