Quick answer: SIBO (small intestinal bacterial overgrowth) is most commonly treated with antibiotics – primarily rifaximin – supplemented by dietary changes and micronutrient supplementation. An accurate diagnosis is essential for effective treatment, which requires the assistance of a specialist gastroenterologist.
Bloating, persistent abdominal discomfort, diarrhoea or even constipation make everyday life difficult for many people. In many cases, these symptoms are not simply due to digestive problems, but indicate SIBO – small intestinal bacterial overgrowth. Treatment for SIBO can only begin once an accurate diagnosis has been made, so it is important to understand exactly what is happening in the body and what options are available.
This article provides a detailed overview of the symptoms of SIBO, diagnostic methods, treatment options, and how Endomedix Gastroenterology can help resolve these symptoms.
What is SIBO, or small intestinal bacterial overgrowth?
Under normal circumstances, there are relatively few bacteria living in the small intestine. In the case of SIBO, however, bacteria – both aerobic and anaerobic microorganisms – proliferate to an abnormal extent in the small intestine. This disrupts digestion and the absorption of nutrients.
It is important to note that SIBO is not a disease in its own right, but is most often the result of another underlying condition – such as a disorder of bowel motility, Coeliac disease, diabetes or previous abdominal surgery. The overgrowth of bacteria can cause fatty diarrhoea (steatorrhoea), malabsorption and vitamin deficiency.
There is also a similar but distinct condition: IMO (Intestinal Methanogen Overgrowth), in which it is not bacteria but methanogens – such as the Methanobrevibacter smithii – they multiply, and this is primarily associated with symptoms of constipation.
What symptoms does SIBO cause?
The symptoms of SIBO are often confused with those of irritable bowel syndrome (IBS) or other digestive problems. The most common symptoms are as follows:
- Bloating and flatulence – especially after a meal
- Cramp-like abdominal pain
- Diarrhoea or loose stools
- Constipation – particularly in the case of the IMO
- Fatty, foul-smelling stools (steatorrhoea)
- Fatigue, weakness
- Weight loss, loss of appetite
In more severe cases, vitamin deficiency may also develop. A deficiency in vitamin B12 is particularly common, as the bacteria bind the cobalamin absorbed from food. This can lead to macrocytic anaemia, peripheral neuropathy, memory problems and hair loss.
If you experience these symptoms, it is advisable to consult a gastroenterologist as soon as possible, as early diagnosis and treatment of SIBO can prevent complications from developing.
How is SIBO diagnosed?
SIBO can be diagnosed using a number of methods, which are selected on the basis of the symptoms and the doctor’s assessment.
Exhalation test: the most common method of examination
The breath test (lactulose- or glucose-based) is non-invasive and is therefore the test of first choice. During the test, the patient consumes a sugar solution – usually 75 g of glucose or 10 g of lactulose – and breath samples are then taken every 15 minutes for 120 minutes.
The assessment thresholds:
- SIBO: an absolute increase in hydrogen levels of ≥ 20 ppm within 90 minutes
- IMO: methane level ≥ 10 ppm at any point during the test
- Hydrogen sulphide and SIBO: ≥ 3 ppm during the test
Strict preparation is required for the test: Antibiotics should be avoided 4 weeks beforehand, laxatives and prokinetic agents 1 week beforehand, complex carbohydrates and dairy products 12 hours beforehand, and smoking and strenuous physical activity on the day of the test.
Microbiological examination of small bowel aspirate
This is the so-called „gold standard” method. During a gastroscopy, a sample is taken from the upper gastrointestinal tract via a sterile catheter and examined in a laboratory. SIBO is confirmed if the bacterial concentration in the jejunal aspirate exceeds 10³ CFU/ml. The most commonly identified pathogens are: Bacteroides, Enterococcus, Lactobacillus.
Endoscopy and laboratory tests
In most patients with SIBO, the endoscopic and histological findings are normal. In severe cases, mucosal oedema, patchy erythema and ulcers may be observed. As an indirect marker, elevated serum folic acid levels and a concurrent reduction in vitamin B12 levels may indicate this condition.
How is SIBO treated?
The treatment of SIBO is based on several pillars: antibiotic therapy forms the foundation, but diet and the replenishment of vitamin deficiencies are also essential for a lasting recovery.
Antibiotic treatment: which medicine should be used and when?
Antibiotic treatment is the cornerstone of SIBO therapy. Rifaximin is the first-line treatment, as it is only minimally absorbed into the bloodstream and exerts its effect directly in the gut.
- In the case of SIBO: rifaximin 2 × 400 mg, for 6 days
- In the case of the IMO: rifaximin 3 × 550 mg + neomycin 2 × 500 mg, administered in combination for 14 days
Other suitable antibiotics: ciprofloxacin, metronidazole, amoxicillin-clavulanic acid, tetracyclines, trimethoprim-sulfamethoxazole. Treatment may be repeated in the event of a relapse, but medical advice must always be sought before repeating the course.
Diet and lifestyle changes for SIBO
Antibiotic treatment alone is not always sufficient. Making changes to your diet reduces the bacteria’s food supply and aids recovery.
Generally recommended criteria:
- Low FODMAP diet: reduces the amount of fermentable carbohydrates, which serve as „fuel” for bacteria
- Reducing carbohydrate intake, in particular, avoiding highly processed foods
- Regular, smaller meals to maintain bowel motility
It is important to emphasise that a diet alone does not cure SIBO – without treatment for the underlying condition, the symptoms will return.
Replenishing micronutrient deficiencies
In more severe cases, SIBO can lead to vitamin deficiencies in the long term. The following may need to be supplemented:
- Vitamin B12 – to prevent neurological symptoms
- Thiamine (B1) and niacin (B3)
- Fat-soluble vitamins (A, D, E, K) – due to oily diarrhoea
- Iron – in cases of anaemia
The dosage and duration of treatment are always determined by a doctor on the basis of laboratory results.
When is it essential to see a doctor if SIBO is suspected?
Not all cases of bloating or abdominal discomfort indicate SIBO, but if certain symptoms are present, you should seek specialist advice without delay:
- Unexplained, unintentional weight loss
- Persistent diarrhoea (lasting more than 30 days)
- Bloody or black stools
- Iron deficiency anaemia
- Severe, cramp-like abdominal pain
- Fever associated with digestive symptoms
These so-called „alarm symptoms” require a thorough investigation, as they may be caused by a more serious digestive disorder.
Endomedix: Gastroenterology and the Treatment of SIBO
The experienced internal medicine and gastroenterology specialists at the Endomedix gastroenterology network possess in-depth knowledge of the diagnosis and treatment of SIBO and related malabsorption disorders. A consultation with a specialist is essential for an accurate diagnosis, during which the doctor will review the symptoms, medical history and the necessary tests.
If you are suffering from persistent bloating, abdominal pain, diarrhoea or other digestive problems, please book an appointment for a specialist gastroenterology consultation at Endomedix. During the consultation, the specialist will draw up a personalised examination and treatment plan, whether this involves a breath test, an endoscopic examination or the assessment of laboratory results.
Endomedix is available in several towns and cities across Hungary – in Budapest, Debrecen, Miskolc, Győr, Gyula, Szolnok, Dombóvár, Veszprém, Siófok and Esztergom – so the right care is close to where you live.
Summary and next steps
The management of SIBO is a complex undertaking that requires an accurate diagnosis, targeted antibiotic therapy, dietary changes and, where necessary, vitamin supplementation. Without treatment of the underlying and associated conditions, symptoms may recur; therefore, ongoing supervision by a gastroenterologist is crucial.
If you have been experiencing digestive problems for some time, don’t put off getting it checked out any longer. Book an appointment at the Endomedix gastroenterology for a consultation with a specialist, and take the first step towards a trouble-free everyday life.
Frequently asked questions about the treatment of SIBO
How long does treatment for SIBO take?
Antibiotic treatment usually lasts 6–14 days, depending on the type of medication and the form of SIBO. Full recovery – including dietary changes and the correction of vitamin deficiencies – can take anywhere from several weeks to a few months.
Can SIBO return after treatment?
Yes, SIBO can recur, particularly if the underlying condition – such as a bowel motility disorder or Crohn’s disease – is not treated properly. To prevent a relapse, it is necessary to treat the underlying cause and to undergo regular gastroenterological check-ups.
What tests can be used to diagnose SIBO?
The most commonly used method is the breath test (glucose- or lactulose-based), which is non-invasive and can be carried out on an outpatient basis. The „gold standard” test is the microbiological analysis of small bowel aspirate, which is performed during a gastroscopy.
Is a special diet required whilst being treated for SIBO?
A low-FODMAP diet and reducing your intake of simple carbohydrates may help to alleviate symptoms and support recovery. However, specific dietary recommendations should always be determined by a doctor or dietitian based on your individual circumstances.
Are probiotics suitable for treating SIBO?
The role of probiotics in SIBO is debated – in some cases, they may even worsen symptoms by introducing further bacteria into the small intestine. Their use should be discussed with your doctor.
What is the link between SIBO and IBS?
The symptoms of the two conditions overlap to a large extent, and SIBO may be diagnosed during investigations for IBS. It is therefore important to rule out SIBO if IBS is suspected, before treatment for IBS begins.
