Gut bacteria overpopulation: symptoms and complications

The overpopulation of intestinal bacteria, from a medical point of view, is known as SIBO —For the translation from English of Small Intestinal Bacteria Overgrowth-. It is estimated that up to 35% of the general population can suffer from this condition, increasing up to 90% in people with previous gastric pathologies.

In primary care, it is common to visit patients for gastrointestinal signs. Therefore, knowing the particularities of each digestive pathology is essential. If you want to know everything about intestinal bacteria overpopulation, keep reading.

Common symptoms in gut bacteria overpopulation

As its name suggests, this disorder involves a excessive growth of commensal and symbiotic microorganisms present in the colon. This causes problems with digestion and intestinal absorption, which results in symptoms such as the following:

  • Loss of appetite
  • Abdominal pain from excess gas.
  • Sickness.
  • Swelling.
  • An uncomfortable feeling of fullness after eating.
  • Diarrhea or constipation
  • Fatigue and weakness

As indicated by the Mayo Clinic, diarrhea, gas and abdominal pain are symptoms of many different conditions, so if they last a few days there is no need to worry. On the other hand, if there is blood or pus in the stool, the discomfort does not disappear in a week or the condition becomes chronic, it is necessary to go to the doctor quickly.

Excessive intestinal gas production manifests as crampy pain in the abdomen.

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Causes and consequences of SIBO

As scientific studies indicate, the overpopulation of intestinal bacteria can be caused by various pathologies. In general, the syndrome appears when a previous surgery or illness makes it difficult and slower for stool to pass through the digestive tract, allowing bacteria to multiply uncontrollably.

Intestinal motility disorders — irritable bowel syndrome (IBS) and functional diarrhea, among many others — and chronic pancreatitis account for nearly 90% of SIBOs. Faced with bacterial overgrowth, the following consequences are observed:

  • Fat malabsorption: Damage to the intestinal mucosa reduces the ability of the intestine to absorb the fats present in food.
  • Poor digestion of carbohydrates: bacteria degrade these nutrients in excess, causing a deficiency of them.
  • Protein malabsorption: damage to the intestinal epithelium hinders the breakdown of proteins into amino acids. These malabsorptions also lead to a worse assimilation of various vitamins.

How is your diagnosis?

As indicated by the portal Empendium, many tests can be performed, but the most indicated is the bacteriological culture of the intestinal content. To do this, a nasojejunal tube equipped with a mechanical protection is used that is introduced into the patient's intestine to obtain a sample of the mucosa.

This technique is considered the gold standard when it comes to diagnosing intestinal bacteria overpopulation. The abnormal results are as follows:

  • Anaerobic bacteria: that is, they are capable of developing in an environment without oxygen. And others like Bacteroides spp., Enterococcus spp., Lactobacillus spp. or E. coli, in a proportion greater than 105 colony forming units (CFU) per milliliter (ml).
  • In sick patients who have undergone intestinal surgery, the value is placed at 103 CFU / ml.

Beyond this, other accessory diagnostic tests are also used, such as stool exams, X-rays of the digestive tract, laboratory tests, and some respiratory tests.

Treatments available for gut bacteria overpopulation

The treatment of this wide pathology must be multidisciplinary. First, if there is an underlying disease that is hampering intestinal motility, it should be addressed as soon as possible.

Once this primary reason has been identified, antibiotics are usually prescribed to the patient to stop bacterial overgrowth. The most widely used are amoxicillin combined with clavulanic acid, metronidazole and rifaximin. The latter is the most prescribed, as it is not absorbed and only works at the intestinal level.

Antibiotics reduce the load of abnormal bacteria. Even so, when they are stopped, they can sometimes reappear. Therefore, the treatments are long-term, alternating drugs to avoid the acquisition of resistance in the colonies.

On the other hand, as indicated by the Spanish Society of Anti-aging and Longevity Medicine (SEMAL), also vitamin supplements may be necessary to counteract malabsorption at the intestinal level. Vitamin B12, calcium and iron supplements are the most prescribed.

The antibiotics of choice for SIBO are varied so that bacterial resistance is not promoted.

Diet tips

Sources already cited They advise reducing the intake of fermentable carbohydrates (FODMAPS) and foods with lactose, as certain intolerance to it can develop during intestinal bacterial overgrowth. To this day, the benefit of introducing probiotics and prebiotics in patients with this clinical picture continues to be investigated.

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Overpopulation of gut bacteria causes pain

As you may have seen, there are many problems that can lead to an overpopulation of intestinal bacteria. From surgeries to little-known syndromes, there are events that can cause intestinal motility to deteriorate, resulting in an exponential growth of commensal microorganisms.

If you have sporadic abdominal pain, don't worry, it is common. In general, it is considered to see a doctor when it persists for more than a few days, especially if it is accompanied by vomiting, nausea, blood in the stool and unintended weight loss.