Intestinal bacterial overgrowth syndrome (SIBO) is a pathological condition caused by the colonization of the small intestine by fecal microflora. SIBO is accompanied by diarrhea and malabsorption of fats and vitamins.

It is a consequence of pathological disorders in the intestines and is caused by the introduction of undigested food residues into the large intestine, promoting the formation of additional colonies of putrefactive and yeast bacteria that disrupt the functioning of the digestive tract. Toxic substances from E. coli, entering the blood, cause intoxication, leading to inflammatory changes in the digestive tract.

Epidemiology

Causes of SIBO

When a baby is born, its intestines are sterile. Over the following weeks, the digestive tract is colonized by streptococci, lactobacilli and enterococci. Further, the number of coli bacteria in the small intestine decreases sharply, and when they multiply in the large intestine, they become the norm.

In the pathological condition of SIBO, cecoileal reflux occurs, leading to increased gas formation and additional stimulation of peristalsis of the small and large intestines.

Risk factors

The reasons leading to the appearance of bacterial overgrowth syndrome in the intestines are: morphological or destructive features in the small intestine, which contribute to partial inhibition of the movement of food through the digestive system. Pathological conditions lead to this: prolonged stress, enteropathies of various etiologies, persistent inflammatory bowel diseases, cholangitis, and the like.

Factors that cause pathological changes in the balance of small intestinal microflora include:

• impaired functioning of the ileocecal valve;
• surgical interventions - formation of a blind loop, cholecystectomy, resection of the small intestine, etc.;
• diseases of the digestive system based on intestinal motility disorders (chronic constipation, gastrostasis, duodenostasis);
• conditions caused by pathological changes in cavity digestion and absorption (maldigestion and malabsorption);
• pathological changes in the pancreas associated with secretory insufficiency;
• pathological conditions of the biliary tract;
• constant nutritional imbalance, intestinal inflammation, diverticula, short bowel syndrome;
• immunosuppressive pathologies in AIDS and chemotherapy, antibiotics;
• tumors of the intestine and surrounding lymph nodes
• Crohn's disease.
• celiac disease.
• hypogammaglobulinemia

Pathogenesis

The pathogenesis of SIBO consists of the following elements:

• Poor absorption of lipids, proteins, polysaccharides, vitamins leads to inhibition of the functions of enterocytes and a bacterial change in the nutrient medium to a state of toxic and non-absorbable.
• Anaerobic flora leads to pathological changes in bile acids and excludes them from the digestive process. Altered acids and fragments of carbohydrates provoke loose stools.
• Anaerobic microorganisms absorb vitamin B12, which leads to the formation of macrocytic anemia.

Symptoms of SIBO

Symptoms of SIBO are as follows: attacks of nausea, increased gas formation, diarrhea, malabsorption syndrome, persistent decrease in body weight. Specific tests such as small intestinal aspiration for culture and breath tests help diagnose SIBO.

Symptoms are divided into two groups:

1. Abdominal, caused by pathological processes in the abdominal cavity, quite frequent bloating and rumbling in the abdomen, sometimes nausea, occurring some time after eating. Stool instability.
2. Are common, which are based on a lack of fat-soluble vitamins, cyanocobalamin and folic acid, iron, leading to decreased performance, fatigue, impotence, lethargy, dizziness, and weight loss. Vitamin deficiency conditions are characterized by dry skin, blurred vision at dusk; increased anxiety, mood swings, nervousness.

Complications and consequences

Diagnosis of SIBO

Careful history taking ensures accurate diagnosis. The patient is questioned in detail about the presence of functional gastrointestinal diseases, accompanied by pain of varying intensity in the abdomen, flatulence, and diarrhea.

Making a diagnosis of SIBO requires the use of laboratory tests and various examination methods (non-invasive, invasive).

It is necessary to culture aspiration masses of the small intestine to determine the type of pathological microflora. A typical diagnostic test is breathing tests.

In the coprogram of SIBO, undigested food remains and the formation of excessive amounts of fat are determined. An intestinoscopy and biopsy of the walls of the small intestine are performed.

Breath test for bacterial overgrowth syndrome

Glucose test. It is based on the identification of hydrogen in the air exhaled by the patient using a special device. It is carried out on an empty stomach. The patient takes a deep breath and holds his breath for 10-15 seconds. Then he exhales slowly into the testing device. The laboratory doctor records the readings of the device. The patient then drinks a solution with added glucose. At intervals of 30 minutes, the specialist takes measurements three times during exhalation. A noticeable increase in hydrogen levels indicates problems in the small intestine.

Xylose test(xylose is a carbohydrate that is absorbed only in the small intestine). This test detects altered CO2, the formation of which is associated with impaired metabolic reactions of the patient’s body caused by SIBO.

Analyzes

When diagnosing bacterial overgrowth syndrome, laboratory tests are recommended: complete blood count - determination of anemia (low hemoglobin, pathologically changed red blood cells, low color index), the presence of inflammation (leukocytosis, increased ESR);

Biochemical blood test (increased ALT, AST, positive C-reactive protein).

General urine test (presence of a large amount of mucus and bacteria).

Scatological examination of stool (detects undigested food debris, increased acidity of stool and high fat content)

Bacteriological culture (detection of rapid growth of colonies of pathological microorganisms).

Instrumental diagnostics

Intestinoscopy is an endoscopic method. A conductor with an optical device is inserted into the patient’s small intestine to aspirate its contents, followed by inoculation of the aspirate on a nutrient medium.

A small intestinal biopsy is an instrumental capture of tissue from the small intestine for the purpose of microscopic examination. In the symptom complex of excessive bacterial growth, pathologically altered atrophic villi in the small intestine are determined.

An x-ray is performed to identify the underlying cause of SIBO (diverticulum, small intestinal stricula, etc.).

Differential diagnosis

SIBO should be differentiated from celiac disease and exocrine pancreatic insufficiency. The pathological changes are very similar: partial villous atrophy, crypt hyperplasia, and accumulation of lymphocytes in the epithelial layer are characteristic of these diseases. Clarification of the differential diagnosis requires specific studies.

SIBO Treatment

Therapy should be of a complex etiopathogenetic nature. It is necessary to eliminate the pathology that caused SIBO.

Patients are treated with antibacterial drugs, vitamins, pro- and prebiotics, and absorbents.

The decision on the choice of antibiotic is based on the results of bacteriological analysis of small intestinal aspirate and tests for the sensitivity of pathological flora to drugs. Patients with SIBO are treated with broad-spectrum antibiotics rifaximin in a daily dose of 1200 mg.

Adults actively use tetracycline antibiotics, for example, tetracycline hydrochloride- 0.5 g 4 rubles/day. Contraindicated in children under 8 years of age. Side effects are expressed in the form of increased intracranial pressure, dizziness, weakness, allergic manifestations, photosensitivity.

Amoxicillin. Adults - 0.25-0.5 g orally 2 times a day; children – 40 mg/kg/day 2 times/day. Possible manifestations of adverse reactions are itching, redness of the skin, Quincke's edema, anaphylactic shock.

For successful treatment of bacterial overgrowth syndrome in the intestines, it is necessary to create unique conditions that have a beneficial effect on the restoration of normal microflora and the colonization of the intestines with bifidobacteria and lactobacilli. Medicines with such properties are called pre- and probiotics.

"Colibacterin". It contains live cultures of the E. coli M-17 strain with antagonism to pathogenic and conditionally pathogenic microflora. Usually take from 6 to 10 doses in one or two doses (take the drug 40 minutes before meals) for a month.

"Bifikol". It combines simultaneously grown bacteria E. coli M-17 and bifidobacteria. The daily norm is from 6 to 10 doses.

Vitamins

Patients who have problems with weight loss or a lack of certain vitamins and minerals are prescribed vitamin preparations, which include vitamin B12, ascorbic acid, fat-soluble vitamins, calcium and magnesium (Undevit, Supradin, Multi-tabs immunoplus, Vitrum, Revit) .

Physiotherapeutic treatment

As a physiotherapeutic treatment for SIBO, warm mineral bicarbonate-chloride and sodium-calcium waters are taken orally. They inhibit intense motor activity and thereby reduce the frequency of bowel movements. In the digestive tract, mineral water restores and corrects various types of metabolism. A reception may be recommended - Borjomi, Narzan, Slavyanovskaya, etc.

Traditional treatment

Curd whey. It is made from kefir, which is placed in hot water, where it undergoes a process of separation into curds and whey. The serum is carefully drained and used for the effective treatment of dysbiosis.

Kefir enema. Kefir (80 g) is heated and administered to the baby before bedtime.

Blueberry jelly to treat SIBO, prepare according to the recipe: mix a tablespoon of blueberries with a tablespoon of starch and a small amount of water. Add another glass of water in a thin stream and, with constant stirring, bring the mixture to a boil. It is recommended to drink jelly warm.

Small intestinal bacterial overgrowth (SIBO), also called microbial overgrowth or small bowel bacterial overgrowth syndrome (SBBOS), is a disease of bacterial overgrowth in the small intestine. Unlike the large intestine (or large intestine), which is teeming with bacteria, the small intestine typically has fewer than 104 organisms per milliliter. Patients with bacterial overgrowth typically develop symptoms including nausea, abdominal bloating, vomiting, diarrhea, malnutrition, weight loss, and malabsorption, which are caused by several mechanisms. Diagnosis of bacterial overgrowth is made using several techniques, with the gold standard being to obtain a small intestinal aspirate that contains more than 105 bacteria per milliliter. Risk factors for the development of bacterial overgrowth include dysmotility, anatomical abnormalities in the intestine including fistulas, diverticula and blind loops resulting from surgery and resection of the ileocecal valve, gastroenteritis caused by changes in the small intestine, and the use of certain medications, including proton pump inhibitors. Small intestinal bacterial overgrowth syndrome can be treated with an elemental diet or, failing that, with antibiotics, which may be given in an intermittent manner to avoid the development of antibiotic resistance, in some cases followed by prokinetics to prevent relapse if the suspected cause is in motor impairment.

Signs and symptoms

Bacterial overgrowth can cause a variety of symptoms, many of which are also seen in other diseases, making diagnosis difficult at times. Many symptoms are related to nutrient malabsorption due to exposure to bacteria that either metabolize nutrients or cause small intestinal inflammation that impairs absorption. Symptoms of bacterial overgrowth include nausea, flatulence, constipation, bloating, abdominal pain or discomfort, diarrhea, fatigue and weakness. Bacterial overgrowth in the small intestine also causes increased small intestinal permeability. Some patients may lose weight. Children with small intestinal bacterial overgrowth may develop malnutrition and may have difficulty achieving adequate growth. Steatorrhea, an oily type of diarrhea when fats are not absorbed properly and end up in the stool, may also occur. Patients with bacterial overgrowth that is prolonged may develop disease complications as a result of malabsorption of nutrients. Anemia can occur through multiple mechanisms, as many of the nutrients involved in red blood cell production are absorbed in the affected small intestine. Iron is absorbed in the more proximal parts of the small intestine, the duodenum and jejunum, and patients with iron malabsorption may develop microcytic anemia with small red blood cells. Vitamin B12 is absorbed in the final part of the small intestine, the ileum, and patients with vitamin B12 malabsorption may develop megaloblastic anemia with large red blood cells. In older adults, small intestinal bacterial overgrowth is associated with an increased incidence of diarrhea, low body mass index, and significantly lower serum albumin concentrations.

Risk factors

Some people are more predisposed to developing bacterial overgrowth due to certain risk factors. These factors can be divided into three categories: (1) impaired motility or movement of the small intestine, or anatomical changes that lead to stasis, (2) diseases of the immune system, and (3) conditions that cause large numbers of bacteria to move from the large intestine to thin. Motor problems can either be widespread or limited to a specific area. Diseases like scleroderma and possibly celiac disease cause widespread slowing of the intestines, leading to increased bacterial concentrations. More often, the small intestine may have anatomical problems, such as bulges known as diverticula, which can cause bacteria to accumulate. After surgery involving the stomach and duodenum (most often Billroth II antrectomy), a blind loop may form, stopping the flow of intestinal contents. This can also cause excess growth and is called blind-loop syndrome. Immune system diseases also cause bacterial overgrowth. Chronic pancreatitis, or inflammation of the pancreas, can cause bacterial overgrowth through mechanisms that influence it. The use of immunosuppressive drugs to treat other diseases can also cause bacterial overgrowth, as evidenced in animal models. Other causes include inherited immunodeficiency conditions such as mixed variable immune deficiency, IgA deficiency, and hypogammaglobulinemia. Ultimately, a disrupted connection between the bacteria-rich colon and small intestine can increase the bacterial load in the small intestine. Patients with Crohn's disease or other diseases of the ileum may require surgery to remove the ileocecal valve connecting the small and large intestines; this leads to an increased influx of bacteria into the small intestine. After bariatric surgery for obesity, connections between the stomach and ileum can form, which can also increase the bacterial load in the small intestine. Proton pump inhibitors, a class of drugs used to reduce the amount of stomach acid, have been associated with an increased risk of developing bacterial overgrowth in the small intestine. In recent years, some links have been suggested between bacterial overgrowth and other diseases. However, the usual methodology for these studies involves the use of breath testing as a proxy test for the presence of bacterial overgrowth. Breath testing has been criticized by some authors as an incomplete test for bacterial overgrowth with a high rate of false-positive results.

Irritable bowel syndrome

Some studies report that up to 80% of patients with irritable bowel syndrome (IBS) have bacterial overgrowth in the small intestine (using a hydrogen breath test). Subsequent studies demonstrated statistically significant relief of irritable bowel syndrome symptoms as a result of treatment of bacterial overgrowth. However, there is little agreement regarding the relationship between irritable bowel syndrome and bacterial overgrowth. Other authors conclude that abnormal breath test results, common among patients with irritable bowel syndrome, do not indicate bacterial overgrowth, and argue that “abnormal fermentation time and the dynamics of breath test results support a role for abnormal distribution of intestinal bacteria in irritable bowel syndrome." Researchers generally agree that breath test results are abnormal in irritable bowel syndrome, but disagree on whether they are a typical sign of bacterial overgrowth. More research is needed to clarify this connection.

Fibromyalgia

Fibromyalgia is a poorly understood pain condition. The lactulose breath test showed that patients with fibromyalgia had more abnormal findings compared to both patients with irritable bowel syndrome and the general population. This study also demonstrated a positive relationship between pain severity and the degree of abnormality in the breath test. A subsequent study also showed a high prevalence of leaky gut, which some believe often accompanies bacterial overgrowth.

Redheads

Gut bacteria may play a causative role in the dermatological condition known as rosacea. A recent study subjected patients to a hydrogen breath test to determine the prevalence of bacterial overgrowth. It found that a significant proportion of patients were hydrogen positive compared to controls, suggesting the presence of bacterial overgrowth (47% vs 5%, p<0,001). Водород-положительные пациенты затем подвергались 10-дневному курсу рифаксимина, неабсорбируемого антибиотика, который не покидает пищеварительный тракт и, таким образом, не попадает в кровоток и кожу. 96% пациентов продемонстрировали полную ремиссию симптомов красных угрей, которые длились свыше 9 месяцев. Данные пациенты также давали отрицательный результат при тестировании на избыточный бактериальный рост. У 4% пациентов, продемонстрировавших рецидив, также был выявлен рецидив избыточного бактериального роста. Данные пациенты проходили второй курс рифаксимина, который снова устранял симптомы красных угрей и нормализовал выведение водорода. В другом исследовании было обнаружено, что некоторые пациенты с красными угрями, которые были водород-отрицательными, все же давали положительный результат в анализе на избыточный бактериальный рост при использовании вместо водородного метанового дыхательного теста. Данные пациенты продемонстрировали незначительные улучшения в ответ на рифаксимин, что было выявлено в предыдущем исследовании, но выявили устранение симптомов красных угрей и нормализацию выведения метана в результате приема антибиотика метронидазола, который направлен на метаногенные кишечные бактерии. Данные результаты свидетельствуют, что оптимальное лечение антибиотиками может варьироваться среди пациентов и что различные виды кишечных бактерий способны содействовать симптомам красных угрей. Это также может объяснить облегчение симптомов, продемонстрированное некоторыми пациентами при употреблении пищи с пониженным содержанием углеводов. Такая пища ограничивает доступность материала, необходимого для бактериальной ферментации и, таким образом, уменьшает популяции кишечных бактерий.

Pathophysiology

Certain types of bacteria are more likely to be found in jejunal aspirates obtained from patients with bacterial overgrowth. The most commonly encountered species include Escherichia coli, Streptococcus, Lactobacillus, Bacteroides, and Enterococcus. Soon after birth, the gastrointestinal tract is colonized by bacteria that, based on animal model studies, grow in a sterile environment and have beneficial effects on gastrointestinal function. There are 500-1000 different types of bacteria that are found in the intestines. However, if the microflora of the small intestine has changed, inflammation or altered digestion may occur, leading to symptoms. Many patients with chronic diarrhea have bacterial overgrowth as a cause and contributing factor to their symptoms. While the generally accepted definition of chronic diarrhea varies, it is generally defined as a change in stool consistency or increased frequency of bowel movements that lasts for more than three weeks. Various mechanisms are involved in the development of diarrhea due to bacterial overgrowth. First, excess concentrations of bacteria can cause direct inflammation of small intestinal cells, leading to inflammatory diarrhea. Malabsorption of fats, proteins and carbohydrates can cause poorly digested foods to enter the large intestine. This can cause diarrhea due to the osmotic pressure of these molecules and also stimulates the secretory mechanisms of colon cells, which leads to secretory diarrhea. There is also overlap between tropical diarrhea, postoperative irritable bowel syndrome, and small intestinal bacterial overgrowth with respect to the pathophysiology of the three conditions, with small intestinal bacterial overgrowth in some cases similarly being initiated by acute gastrointestinal infection.

Diagnostics

Doctors diagnose bacterial overgrowth in a variety of ways. Malabsorption can be detected using a test called the D-xylose test. Xylose is a sugar that does not require enzymes to be digested. The D-xylose test involves the patient drinking a drink containing a specified amount of D-xylose and measuring its levels in the urine and blood; if there is no evidence of D-xylose in the urine and blood, it means the small intestine is not absorbing properly (the opposite of problems where enzymes are required for digestion). The gold standard for detecting bacterial overgrowth is to obtain a small intestinal sample containing more than 105 bacteria per milliliter. The normal small intestine has less than 104 bacteria per milliliter. Some experts, however, consider receiving a sample with a bacterial count of more than 103 to be a positive result if the microflora is predominantly colonic types of bacteria, since bacteria of this type are considered pathological in excess quantities in the small intestine. The reliability of sample collection in diagnosing bacterial overgrowth has been questioned because bacterial overgrowth may be focal and reproducibility may be less than 38 percent. Breath tests have their own problems with reliability due to a high rate of false positive results. Some doctors consider a patient's response to treatment as part of the diagnosis. Breath tests have been developed to test for bacterial overgrowth based on bacterial metabolism of carbohydrates into hydrogen and/or methane, or based on the detection of byproducts of carbohydrate digestion that are not normally metabolized. The hydrogen breath test involves fasting the patient for at least 12 hours and then ingesting a drinking substrate, usually glucose or lactulose, after which the exhaled concentration of hydrogen or methane is measured, usually after 2–3 hours. It is comparable to obtaining jejunal samples in making the diagnosis of bacterial overgrowth. Tests conditioned by 13C and 14C and based on bacterial metabolism of D-xylose have also been developed. Elevated bacterial concentrations have also been implicated in bile acid deconjugation. The glycocholic acid breath test involves taking the bile acid 14C glycocholic acid and detecting 14CO2, which will be elevated if bacterial overgrowth is present. Some patients with symptoms of bacterial overgrowth undergo gastroscopy, or imaging of the stomach and duodenum using an endoscopic camera. Small intestinal biopsy findings of bacterial overgrowth may mimic celiac disease, making diagnosis more challenging. Findings include blunting of the villi, hyperplasia of the glandular cavities, and increased numbers of lymphocytes in the stratum propria. However, some doctors suggest that if the suspicion of bacterial overgrowth is strong enough, the best diagnostic test is a treatment trial. If symptoms improve, empirical diagnosis of bacterial overgrowth may be performed.

Treatment

Bacterial overgrowth can usually be treated with a course of antibiotics, although whether antibiotics should be considered a first-line treatment is a matter of debate. Some experts recommend probiotics as first-line therapy, with antibiotics considered as second-line treatment for more severe cases of bacterial overgrowth. Prokinetics are other adjunctive agents, but human studies are limited. A variety of antibiotics are used, including tetracycline, amoxicillin-clavulanate, fluoroquinolones, metronidazole, neomycin, cephalexin, trimethoprim-sulfomethaxazole, and nitazoxanide; however, the best evidence exists for the use of rifaximin. A week's course of antibiotics is usually sufficient to treat the condition. However, if a relapse occurs, antibiotics may be given in an intermittent manner to avoid the development of antibiotic resistance. For example, antibiotics may be taken for a week, followed by a three-week break, followed by another week of antibiotics. Alternatively, the antibiotics used may be alternated. A condition that predisposes a patient to bacterial overgrowth should also be treated. For example, if bacterial overgrowth is caused by chronic pancreatitis, the patient should be treated with pancreatic enzyme coating supplements. Probiotics are bacterial preparations that change the bacterial microflora in the intestines and have a beneficial effect. Animal studies have demonstrated that probiotics improve resistance, have antibacterial, immunostimulating, and anti-inflammatory effects, which may be beneficial in treating bacterial overgrowth in humans. Lactobacillus casei is effective in improving breath hydrogen scores after 6 weeks of treatment, primarily by inhibiting the overgrowth of fermenting bacteria in the small intestine. Multi-strain VSL#3 is also effective in inhibiting bacterial overgrowth. Lactobacillus plantarum, Lactobacillus acidophilus and Lactobacillus casei have demonstrated effectiveness in the treatment and management of bacterial overgrowth. On the contrary, Lactobacillus fermentum and Saccharomycetes boulardii were ineffective. The combination of Lactobacillus plantarum and Lactobacillus rhamnosus was effective in inhibiting the overgrowth of organisms responsible for producing abnormal amounts of gas in the small intestine. Probiotics are superior to antibiotics in treating bacterial overgrowth. Combining probiotic strains produces better results than therapy using the antibiotic metronidazole, and probiotics are effective in treating and preventing secondary lactase deficiency and bacterial overgrowth in the small intestine in people suffering from post-operative irritable bowel syndrome. Probiotics taken for uncomplicated cases of bacterial overgrowth usually lead to resolution of symptoms. Continuous probiotic therapy may be required to prevent recurrence of gas-producing bacteria overgrowth. Probiotic yogurts may also be effective in treating bacterial overgrowth, as there has been evidence of inflammation relief after 4 weeks of supplementation. An elemental diet for two weeks provides an alternative to antibiotics for eliminating bacterial overgrowth. The elemental diet works by providing the subject with nutrition, but depriving bacteria of a source of nutrition. Additional treatment includes the use of prokinetic agents such as 5-HT4 receptor agonists or motilin agonists, extending to periods without bacterial overgrowth following treatment with an elemental diet or antibiotics. A diet devoid of certain foods that feed bacteria may help relieve symptoms. For example, if symptoms are caused by bacterial overgrowth that feeds on foods rich in indigestible carbohydrates, a restricted diet containing fermentable oligo-, di-, monosaccharides and polyols may help.

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List of used literature:

Quigley E, Quera R; Quera (2006). "Small intestinal bacterial overgrowth: roles of antibiotics, prebiotics, and probiotics." Gastroenterology 130(2 Suppl 1):S78–90. doi:10.1053/j.gastro.2005.11.046. PMID 16473077.

Teo M, Chung S, Chitti L, Tran C, Kritas S, Butler R, Cummins A; Chung; Chitti; Tran; Kritas; Butler; Cummins (2004). "Small bacterial overgrowth is a common cause of chronic diarrhea." J Gastroenterol Hepatol 19(8):904–9. doi:10.1111/j.1440-1746.2004.03376.x. PMID 15242494.

Sachdev, A.H.; Pimentel, M. (Sep 2013). "Gastrointestinal bacterial overgrowth: pathogenesis and clinical significance." Ther Adv Chronic Dis 4(5):223–31. doi:10.1177/2040622313496126. PMID 23997926.

The gastrointestinal tract of the body is seeded with several hundred different types of bacteria. The composition of microorganisms varies in sections more or less distant from the median plane of the small intestine. Microflora is of great importance for normalizing the smooth functioning of the intestines. For a person without health problems, as a rule, various microorganisms serve to maintain a normal acid-base balance in the stomach, promote the production of gastric juice for food processing, and control the motor activity of the small intestine. If at least one of these devices malfunctions, there is a high probability of the formation of bacterial overgrowth syndrome in the small intestine.

Definition

Bacterial overgrowth in the small intestine occurs as a consequence of changes associated with human anatomy, or due to disturbances in the motor activity of the gastrointestinal tract and insufficient gastric secretion. The resulting disturbances can lead to nutritional problems, loss of vitamins and failure of fat digestion. Bacterial overload syndrome is treated with the use of antibacterial drugs.

Symptoms

Patients with bacterial overgrowth syndrome experience the following symptoms:

• painful bloating, rumbling, which occurs a short time after eating food;
• mainly diarrhea;
• poorly digested food in stool;
• the presence of fat inclusions in the stool;
• decreased vision;
• in rare cases, nausea is observed;
• prostration;
• headache;
• sudden weight loss;
• feeling of anxiety, panic;
• mostly bad mood;
• dizziness;
• depressive state.

Forms of the disease

Bacterial increase in the small intestines depends on the amount and nature of the microflora and comes in three degrees:

1. The first degree is aerobic, i.e., to perform the vital functions of a group of living organisms invisible to the naked eye, oxygen is required, with an increased intestinal microflora.
2. The second degree in the syndrome is an aerobic intestinal increased microflora with the formation of bacteria. In this case, oxygen is not required to perform the vital functions of microorganisms.
3. The third degree has the majority of anaerobic microflora.

Source of the disease

Small bowel bacterial overgrowth is a phenomenon that can occur for a number of reasons. Basically, the causes are divided into those that study the origin of the disease, their conditions, as well as those that are based on the study of the development of the disease.

Based on etiology, the following causes of bacterial growth are distinguished:

• Excessive levels of bacteria in the intestine may occur after operations;
• disturbances in the functionality of the Bauginian valve;
• diseases of the digestive system that are associated with intestinal motor activity;
• long-term eating disorder;
• damage in the intestinal cavity under the influence of digestive and absorption enzymes;
• the structure of the intestine, namely the narrowing of its lumen;
• various food intolerances;
• chronic inflammatory diseases in the intestines;
• obstruction;
• symptom complex of chronic disorders;
• diverticular disease;
• cirrhosis of the liver;
• alcoholism;
• vagatomy;
• prolonged use of medications that reduce the human immune system;
• excessive antibiotic therapy;
• bacteria that come from the extraintestinal site;
• all kinds of stress;
• local and systemic immune system disorders;
• diabetes.

As a result of exposure to etiological signs, the protective layer of the mucous membrane of the small intestine is disrupted. As a result, local and systemic pathological processes are caused, the protective purpose of the mucous membrane and the functioning of digestive enzymes are disrupted. In addition, there is a disorder of secretion, oxidation of fatty acids, and endogenous intoxication.

In case of serious disorders of the human immune system, an exchange of bacteria into the lymph and blood can occur, followed by the development of inflammation with pus on all kinds of tissues and organs.

Diagnosis and treatment

Diagnostics makes it possible to make an accurate diagnosis and identify bacterial overgrowth. Thus, diagnostics may include:

• Collecting information about the patient’s family in order to identify through family relationships the presence of diseases associated with the digestive system.
• Analyzing the patient’s complaints and past illnesses, as well as studying the patient’s stool (consistency, duration). In addition, flatulence and nausea are taken into account.
• Visual examination of the patient, which is based on assessing the patient’s skin color, physique and determining the presence of excess weight.
• Collection of information about existing diseases of the gastrointestinal tract and previous operations and other diseases.

Diagnosis necessarily includes laboratory tests, which are based on donating blood for a general analysis, which will show or refute anemia, an increase in the level of leukocytes, which happens during an inflammatory process in the body. In addition, a biochemical blood test should be performed, which will identify the root cause of the disease, and a general urine test, which is necessary to determine the increase in possible chemical substances indicating the development of bacteria that exceed the norm. To make an accurate diagnosis and determine the root cause, it is important to conduct a canal analysis, which will indicate the presence or absence of undigested food, determine the acidity of the stool and the amount of fat in it.

An important research method is the breath test. Before testing, you should adhere to a number of rules: it is forbidden to eat food containing carbohydrates in the evening before testing; do not smoke or overload the body with physical activity several hours before the test; Use an antibacterial mouth rinse before testing. Another equally important diagnostic method is a test with sugar, which will show hydrogen in bacterial growth, as well as a test with xylose, which is necessary to detect labeled carbon dioxide.

Diagnosis of bacterial overgrowth syndrome is based on instrumental research:

• X-ray, which is necessary to detect diverticulosis or narrowing of the small intestine.
• The Schilling test, which involves the patient taking vitamin B12 and then excreting it in the urine. The doctor evaluates the absorption of the vitamin.
• Biopsy of the small intestine. To do this, a piece of tissue is taken and sent for examination under a microscope. If the diagnosis of the disease is confirmed, an abnormal change in the intestinal mucosa occurs.

If there is excessive bacterial growth, the following specialists should be consulted:

• a surgeon who will rule out surgical pathologies;
• gynecologist – necessary to exclude gynecological pathologies;
• a urologist, consultation with whom will rule out urinary pathologies;
• an infectious disease specialist, consultation with whom is carried out if indicated and is necessary to exclude infectious diarrhea.

Treatment of increased bacterial growth in the small intestine is based on reducing or completely eliminating the symptoms of the primary disease, eliminating the excessive presence of bacteria in the small intestine, restoring the microbiocenosis and normalizing the functioning of the digestive system. Therapy can be carried out with or without medication.

Non-drug treatment consists of following the necessary diet and eating foods of natural origin. These products include fermented milk products containing bifidobacteria. Treatment of the syndrome with drugs is based on therapy with antibacterial drugs, probiotics, and prebiotics. If necessary, intravenous vitamin therapy is prescribed.

Surgical intervention is performed in case of unsuccessful drug and non-drug treatment.

With bacterial overgrowth syndrome in the intestines, the number of bacteria that represent normal microflora increases. This rarely leads to gastroenterological diseases and does not directly affect the patient's life expectancy.

In some cases, pathogenic microorganisms may appear. But, as a rule, it is not this that negatively affects the quality of life, but bloating, gas formation, heartburn, nausea and other constant manifestations of SIBO. A set of symptoms may appear after various surgical interventions, with impaired peristalsis or changes in acidity levels.

Description of SIBO

Normally, the mass of bacteria in the intestines of an adult is about 2.5 kg. Moreover, the total genome includes 400 thousand genes, which is 12 times more than the human genome. The small intestine contains about 100 microorganisms per ml. In the intestinal flora of the large intestine, their number is much higher - 1010-1012 per 1 ml. Most microorganisms are destroyed by gastric acid. The microflora is partially represented by opportunistic organisms. Bacteria also have a physiological function: they break down food during the fermentation process. In total, there are from 500 to 1,000 different strains of microorganisms living in the gastrointestinal tract.

With bacterial overgrowth syndrome, microorganisms appear in the small intestine that are qualitatively and quantitatively similar to the microflora of the large intestine. As a result, an inflammatory process develops and the functional functioning of the entire digestive tract is disrupted. Microorganisms metabolize vitamins, leading to malnutrition. Bacteria activate the premature process of divergence of acid salts, contributing to malabsorption and deficiency of nutrients. Also, with excessive bacterial growth in the small intestine, patients experience pathological changes in the mucosa. This can lead to other digestive system diseases.

So what is bacterial overgrowth syndrome? This is a pathological condition characterized by changes in microflora in the small intestine. The syndrome leads to functional disorders in the digestive system, which is manifested by a number of symptoms. Most often, patients experience diarrhea and the process of transport of nutrients is disrupted. Usually (but not necessarily) intestinal bacterial overgrowth syndrome occurs against the background of another disease.

Risk factors

At risk for developing intestinal bacterial overgrowth syndrome are young children (including newborns, whose gastrointestinal tract is just beginning to be colonized by bacteria) and the elderly. According to statistics, SIBO develops in approximately 20-43% of patients with diabetes.

A complex of symptoms is also typical for people with eating disorders and eating disorders. Bulimia, anorexia, periodic episodes of overeating, irregular and irrational nutrition with a deficiency of vitamins and nutrients can also lead to bacterial overgrowth syndrome (SIBO).

In half of cases, the cause of neonatal chronic diarrhea is SIBO. Microflora can also change after taking a course of antibiotics, with nutritional disorders (for example, eating foods that are not appropriate for age), intestinal infections and lactase deficiency.

The following phenomena also contribute to the occurrence of bacterial overgrowth syndrome in the intestines (symptoms will be described below):

• anatomical changes that contribute to a delay in the passage of contents through the gastrointestinal tract;
• absence of ileocecal valve;
• various peristalsis disorders;
• increased secretion of hydrochloric acid;
• immune system disorders;
• the use of certain pharmaceutical drugs (for example, proton pump inhibitors, which inhibit the secretion of hydrochloric acid).

Main symptoms

The clinical picture of the disease is varied. Among the symptoms of bacterial overgrowth in the intestines, doctors distinguish abdominal (associated with the abdominal cavity) and general. Abdominal manifestations include:

• flatulence (rumbling in the stomach, bloating) that occurs a short time after eating;
• irregular bowel movements with frequent bouts of diarrhea;
• the presence of undigested food particles in the stool.

Rarely, patients experience nausea.

Common symptoms include:

• various neurotic disorders (frequent mood swings, hysteria, anxiety, insomnia);
• weight loss;
• signs of deficiency of iron, folic acid, vitamins D, K, A, E.

The latter also has its symptoms, expressed as:

• general weakness and drowsiness throughout the day;
• rapid fatigue;
• visual impairment;
• frequent headaches and dizziness;
• decreased visual acuity;
• dry skin.

Possible signs of hematopoietic disorders. Children may experience growth retardation.

Why is bacterial overgrowth dangerous? All characteristic symptoms of SIRD do not threaten the patient’s life, but negatively affect its quality. Over time, psychological and other health problems may increase, because all processes in the human body are interconnected.

Forms of the disease

Depending on the amount and nature of the microflora, doctors distinguish three forms of the disease. The first degree of SIBO is characterized by an increase in aerobic microflora (bacteria that require air to function predominate). At the second stage, anaerobic microorganisms appear. These are those who do not need access to oxygen for normal existence. The third stage is characterized by the predominance of anaerobic microflora in the gastrointestinal tract.

Diagnostic methods

Diagnosis and treatment of gut bacteria overgrowth begins with an assessment of the patient's overall health because SIBO is typically caused by underlying medical conditions or as a result of eating disorders. Often the cause of SIBO, for example, can be irritable bowel syndrome - a functional disorder accompanied by bloating, abdominal pain, discomfort in the absence of structural lesions of the gastrointestinal tract. In half of the cases, this diagnosis leads to increased bacterial growth.

The doctor needs to rule out:

• valve malfunction;
• diseases associated with intestinal motility disorders;
• long-term nutritional imbalance;
• inflammatory diseases of the gastrointestinal tract (especially chronic);
• short bowel syndrome;
• immune disorders (local and systemic, including chemical or radiation exposure, AIDS);
• entry of bacteria from the extraintestinal reservoir;
• patient taking antibiotics;
• intestinal tumors.

Cleansing with enemas and various diets have a negative impact. Intestinal bacterial overgrowth syndrome can also be caused by stress of various origins.

SIBO should be suspected in patients who complain of uncontrolled weight loss, flatulence, bloating, discomfort, and frequent diarrhea. The diagnosis is made based on the results of microflora culture. For this purpose, intestinal contents are aspirated and inoculated onto a nutrient medium.

Stool culture, which is widely used in domestic medicine, is already considered uninformative in international practice, since it can only give an idea of ​​12-15 types of bacteria. This method, however, can be used to identify specific infectious agents.

The diagnosis is made after a hydrogen breath test with glucose and lactose. Both studies are usually easily tolerated by patients. It is necessary to drink a sugar solution, after which the hydrogen content in the exhaled air is determined. The milk sugar test additionally evaluates blood glucose. Increased levels indicate excessive gas formation. A breath test may also be used to examine jejunal secretions.

Additionally, a general blood test is indicated. The following may indicate SIBO and anemia:

• decreased hemoglobin (with excessive bacterial growth it decreases due to impaired absorption of B12 and iron);
• low protein;
• decreased albumin level.

Due to impaired glucose absorption, blood sugar levels may decrease.

For dermatological problems combined with gastrointestinal symptoms, a selenium test is especially important. SIBO confirms a deficiency of this element. The exact scope of the examination is determined by the attending physician based on the medical history and anamnesis.

SIBO Treatment

After determining the exact diagnosis, the doctor is faced with the question of choosing treatment tactics. Intestinal bacterial overgrowth syndrome involves:

• antibacterial therapy;
• if necessary, taking probiotics and prebiotics to restore normal gastrointestinal microflora;
• antidiarrheal and painkillers as indicated.

The treatment regimen must include measures to relieve the underlying disease. How to treat bacterial overgrowth syndrome? A therapeutic diet can lead to an improvement in the patient's condition. Sometimes surgical treatment is necessary: ​​if SIBO has developed against the background of anatomical pathologies in the structure of the digestive system.

After a course of antibiotics that lasts at least two weeks, it is recommended to monitor the patient for several months. At the same time, the best results can be achieved if the main attention is paid not to eliminating symptoms, but to treating the underlying disease.

• Tetracycline is usually effective if the syndrome is not idiopathic (of unclear origin);
• patients with diabetes are prescribed Amoxicillin or clavulanic acid;
• for elderly patients, Metronidazole and Clindamycin are recommended;
• “Gentamicin” (judging by reviews from parents) improves the health of children up to one year old.

The listed drugs may be produced under different trade names. “Gentamicin”, for example, is “Gentamin”, and “Amgent”, and “Gentsin”, and “Septopal”, and “Gentamisin”. Indicated for use in bacterial infections. Contraindications include hypersensitivity, neonatal period and prematurity, lactation period and old age. In some cases, it can be used for newborns less than one week old. This is an antibacterial drug for intramuscular or intravenous administration, so self-medication is strictly contraindicated. All of the above medications can only be purchased with a doctor's prescription.

Special diet

During treatment, it is very important for the patient to follow the therapeutic regimen developed by the doctor and take medications in precise dosages. Judging by the reviews, deviation from therapy tactics may not only not give any positive results, but also lead to disastrous consequences. Additionally, you should avoid stress, eat small meals and exclusively according to the treatment menu.

The diet should be based on foods that are easily digestible. Avoid sweeteners, limit sugar, avoid dairy products, drink at least eight glasses of clean water per day, and consume the recommended amount of protein (120-140 grams of beef or poultry per day).

It is imperative to include fresh, boiled or lightly stewed vegetables and fruits in moderate quantities in your diet, which will normalize stool. Rice (except wild rice), pasta, bread and potatoes are acceptable. But each meal should include no more than half a cup of these foods.

Possible complications

Over a long period of time, bacterial overgrowth syndrome leads to a deficiency of vitamins and microelements. Anemia may develop due to a lack of vitamin B12.

Typically, SIBO is not an independent disease, so complications and prognosis largely depend on the underlying pathology that led to its formation. If it is not eliminated, then unpleasant symptoms from the gastrointestinal tract will regularly recur.

Prevention

Successful treatment of intestinal bacterial overgrowth syndrome usually begins with differential diagnosis and identification of concomitant diseases, because SIBO is rarely an independent pathology. For this reason, the main preventive measure is timely detection and diagnosis-appropriate treatment of any infectious and non-infectious gastrointestinal diseases, regular medical supervision in case of digestive problems and following all doctor’s recommendations.

Patients (especially those at risk) are advised to follow the rules of a balanced diet in everyday life, not to overeat or starve, and to abandon strict diets for weight loss and home colon cleanses, which usually do not lead to anything good. It is advisable to avoid stress, ensure the normal functioning of the immune system and ensure sufficient physical activity. These are general rules for a healthy lifestyle.

Finally

The description, diagnosis and treatment of intestinal bacterial overgrowth syndrome have been discussed in detail above. The clinical symptoms of the syndrome are nonspecific, but can cause significant disruption of the entire digestive system. Diagnostic methods are predominantly non-invasive. Treatment of bacterial overgrowth syndrome in the small intestine is carried out with the use of antibiotics, probiotics, adherence to a therapeutic diet, correction of eating habits and treatment of the underlying disease. Judging by patient reviews, the prognosis is usually entirely determined by the course of the pathology that caused SIRS.

The clinical picture of the disease (the totality of manifestations of the disease) is varied. Among the symptoms there are 2 groups.

• Abdominal (associated with the abdominal cavity) symptoms:
  • symptoms of flatulence (rumbling, bloating), usually occurring within a short period of time after eating;
  • unstable stool with a tendency to diarrhea (frequent loose stools);
  • Lienterea (undigested food fragments in stool);
  • steatorrhea (excretion of excess fat in stool);
  • nausea (occurs rarely).

• Are common (related to all organs and systems) symptoms:
  • signs of deficiency of fat-soluble vitamins (A, D, E, K), cyanocobalamin (a substance that increases hematopoiesis (blood formation)) and folic acid, iron: weakness, fatigue, headaches and dizziness, dry skin, decreased visual acuity at dusk;
  • neurotic disorders (anxiety, bad mood, hysteria);
  • weight loss.

Forms

Depending on the character And amount of microflora in the small intestine there are 3 degrees:

• Ι degree – aerobic (microorganisms whose life requires access to oxygen) intestinal microflora is increased;
• ΙΙ degree - aerobic intestinal microflora is increased, anaerobic bacteria appear (microorganisms whose life activity does not require access to oxygen);
• ΙΙΙ degree – predominance of anaerobic microflora.

Causes

• Irritable bowel syndrome (IBS). Functional intestinal disease, accompanied by abdominal pain, bloating, discomfort in the absence of any organic (structural) damage. With irritable bowel syndrome, at least half of the cases occur with bacterial overgrowth.
• Diverticular bowel disease (a disease characterized by the formation of diverticula (pouch-like protrusions) of the intestinal wall).
• Intestinal stricture (narrowing of the intestinal lumen caused by changes in the intestinal wall).
• Small-bowel anastomoses (surgical connection of the small and large intestines (for example, for colon cancer (a malignant (tumor cell type is not similar to the cell type of the organ from which it originated) tumor, for the treatment of which part of the colon is removed)).
• Obstructions (obstructions in the passage of the intestines) associated with Crohn's disease (a disease of the gastrointestinal tract characterized by inflammation, enlarged lymph nodes, and the formation of ulcers (deep defects) on the mucous membranes of the gastrointestinal tract).
• Chronic pancreatitis (chronic inflammation of the pancreas).
• Cirrhosis of the liver (scarring and deformation of the organ resulting from infectious diseases, intoxication (poisoning) of the body, etc.).
• Scleroderma (a rare connective tissue disease that causes thickening and decreased elasticity of the skin).
• Tropical sprue (severe inflammation of the mucous membranes of the intestines, which leads to impaired absorption of nutrients; most often occurs in people returning from countries with a tropical climate).
• Diabetes mellitus (a disease that develops when there is a lack of the hormone insulin or the absence of its effect on cells, resulting in increased blood sugar levels).
• Amyloidosis is a disease that develops due to the deposition in organs of a special substance - amyloid (which is a mixture of proteins and saccharides (substances related to carbohydrates - compounds that are integral components of cells and tissues of the body)).
• Autoimmune gastritis (inflammation of the gastric mucosa).
• Vagatomy (removal of nerve trunks) and resection (removal of part) of the stomach.
• Hypochlorhydria (reduced secretion of hydrochloric acid in gastric juice), achlorhydria (lack of hydrochloric acid in gastric juice). To date, the effect of long-term use of antisecretory drugs (suppressing the production of gastric juice by the glands) is being discussed, but no convincing data have yet been obtained.
• Diseases accompanied by immunodeficiency (decreased immunity):
  • alcoholism;
  • acquired immunodeficiency syndrome (AIDS) is the terminal (final) stage of infection with the human immunodeficiency virus.
• Long-term treatment with drugs that reduce immunity.

Diagnostics

• Analysis of the medical history and complaints (when (how long ago) did diarrhea (loose, frequent stools), nausea, rumbling in the abdomen and bloating appear; what does the patient associate with the occurrence of these symptoms).
• Analysis of the patient’s life history (the presence of diseases of the gastrointestinal tract (for example, irritable bowel syndrome (a functional bowel disease accompanied by abdominal pain, bloating, discomfort in the absence of any organic (structural) lesion); diverticular bowel disease (diseases characterized by the formation of diverticula (pouch-like protrusions) of the intestinal wall)), other previous diseases, operations).
• Analysis of family history (presence of diseases of the gastrointestinal tract in relatives).
• Objective examination data (assessment of skin color, physique, determination of obesity).
• Laboratory data.
  • Complete blood count (to identify possible anemia (anemia), leukocytosis (increased leukocytes (white blood cells) in the blood during inflammatory diseases)).
  • Biochemical blood test (to identify diseases that accompany or cause this condition).
  • Urinalysis (to detect increases in certain chemicals that indicate the development of bacterial overgrowth).
  • Scatological examination (stool analysis): to identify undigested food fragments, determine the acidity (pH) of the stool, and also determine the amount of fat contained in the stool (with excessive bacterial growth, the fat content in the stool is increased).

• Breathing tests. Before conducting breath tests, it is necessary to inform the patient about the importance of following a number of rules before the test. These include: a ban on consuming carbohydrate foods the night before the test (bread, pasta), abstaining from smoking and physical activity for at least 2-3 hours before testing, using a mouth rinse with an antibacterial effect before testing.
  • A test with glucose (sugar), after consumption of which, in the presence of bacterial overgrowth, hydrogen (a chemical element) is detected in the exhaled air.
  • The test with xylose (a substance related to carbohydrates - compounds that are integral components of cells and tissues of the body) is based on the detection of labeled carbon dioxide (carbon dioxide is labeled with a special substance, after which it is easy to detect) which is formed as a result of the metabolism (metabolic reactions) of microorganisms that a lot in bacterial overgrowth syndrome.
  • A breath test to assess bile acid levels is based on the detection of large amounts of carbon dioxide in the exhaled air.
• Instrumental research.
  • Schilling test. It is carried out to assess the absorption of vitamin B12. The patient receives vitamin B12, after which the doctor assesses how much of it is excreted in the urine. If the readings are low, this may indicate the presence of bacterial overgrowth. Can only be used if the potential benefit to the mother is higher than the risk of complications in the fetus.
  • Intestinoscopy (endoscopic (insertion of an elastic tube with an optical device (endoscope) into the body) examination of the small intestine) with aspiration (sucking) of the contents of the small intestine and inoculation of the aspirate (contents of the small intestine, which was taken during aspiration) on a nutrient medium (substance or mixture of substances, used for growing microorganisms). The concentration of microorganisms in the small intestine is greater than 10 5 cells/ml - convincing evidence in favor of the presence of the syndrome. The test can only be used if the potential benefit to the mother is greater than the risk of complications in the fetus, since it is performed under general anesthesia.
  • Small intestinal biopsy (removal of tissue from the small intestine for microscopic examination). Bacterial overgrowth syndrome involves pathological (abnormal) changes in the lining of the small intestine.
  • X-ray examination - carried out to determine diverticulosis (formation of pouch-like protrusions of the intestinal wall) or stricture (narrowing) of the small intestine.
• Consultation is also possible.

Treatment of bacterial overgrowth syndrome

Treatment must be comprehensive: it is necessary to treat both the disease that caused bacterial overgrowth syndrome and the syndrome itself.

• Antibiotics (drugs that destroy microorganisms and suppress their reproduction). Drugs used:
  • broad spectrum of action (destroying all microorganisms);
  • not absorbed in the intestines (recently such antibiotics are used more and more often).
• Adsorbents (substances capable of absorbing harmful substances). Prescribed in a short course (7–10 days) followed by prebiotics (substances that cause active growth of beneficial microorganisms).

Complications and consequences

If the cause that led to the occurrence of bacterial overgrowth syndrome is not eliminated, it can recur (renew).

Complications occur during a long course of the disease:

• weight loss due to malnutrition (malabsorption of nutrients in the intestines);
• hypovitaminosis (decreased levels of vitamins in the blood, especially vitamin B12);
• B12-deficiency anemia (a disease that develops when there is insufficient supply of vitamin B12 in the body, as a result of which its hematopoietic function (helping in the creation of red blood cells) is impaired).

Prevention of bacterial overgrowth syndrome

Prevention of bacterial overgrowth syndrome comes down to preventing the disease that caused it, for example:

• irritable bowel syndrome (a functional bowel disease accompanied by abdominal pain, bloating, discomfort in the absence of any organic (structural) damage);
• diverticular disease of the intestine (a disease characterized by the formation of diverticula (pouch-like protrusions) of the intestinal wall).