Normal gut microorganisms Are colonies of bacteria that populate the lumen of the lower digestive tract and the surface of the mucous membrane. They are needed for high-quality digestion of chyme (food lump), metabolism and activation of local defense against infectious pathogens, as well as toxic products.

Normal intestinal microflora- this is the balance of various microbes of the lower parts of the digestive system, that is, their quantitative and qualitative ratio, necessary to maintain the biochemical, metabolic, immunological balance of the body and preserve human health.

• Protective function. Normal microflora has a pronounced resistance against pathogenic and opportunistic microorganisms. Beneficial bacteria prevent the colonization of the intestines with other infectious pathogens not characteristic of it. In the case of a decrease in the amount of normal microflora, potentially dangerous microorganisms begin to multiply. Purulent-inflammatory processes develop, bacterial blood poisoning (septicemia) occurs. Therefore, it is important not to allow a decrease in the amount of normal microflora.
• Digestive function. The intestinal microflora is involved in the fermentation of proteins, fats, high molecular weight carbohydrates. Beneficial bacteria destroy the bulk of fiber and chyme residues under the action of water, maintain the necessary acidity level (pH) in the intestine. Microflora inactivates (alkaline phosphatase, enterokinase), participates in the formation of protein breakdown products (phenol, indole, skatole) and stimulates peristalsis. Also, microorganisms of the digestive tract regulate the metabolism of bile acids. Promote the transformation of bilirubin (bile pigment) into stercobilin and urobilin. Beneficial bacteria play an important role in the final stages of cholesterol conversion. Coprosterol is formed from it, which is not absorbed in the large intestine and is excreted in the feces. Normal flora is able to reduce the production of bile acids by the liver and control normal cholesterol levels in the body.
• Synthetic (metabolic) function. Beneficial bacteria of the digestive tract produce vitamins (C, K, H, PP, E, group B) and essential amino acids. The intestinal microflora promotes better absorption of iron and calcium, therefore, prevents the development of diseases such as anemia and rickets. Due to the action of beneficial bacteria, there is an active absorption of vitamins (D 3, B 12 and folic acid), which regulate the hematopoietic system. The metabolic function of the intestinal microflora is also manifested in their ability to synthesize antibiotic-like substances (acidophilus, lactocidin, colicin and others) and biologically active compounds (histamine, dimethylamine, tyramine, etc.), which prevent the growth and reproduction of pathogenic microorganisms.
• Detoxification function. This function is associated with the ability of the intestinal microflora to reduce the amount and remove hazardous toxic products with feces: salts of heavy metals, nitrites, mutagens, xenobiotics, and others. Harmful compounds are not retained in the tissues of the body. Beneficial bacteria prevent their toxic effects.
• Immune function. The intestinal flora stimulates the synthesis of immunoglobulins - special proteins that increase the body's defenses against dangerous infections. Also, beneficial bacteria contribute to the maturation of the system of phagocytic cells (nonspecific immunity), capable of absorbing and destroying pathogenic microbes (see).

Representatives of the intestinal microflora

The entire intestinal microflora is divided into:

1. normal (basic);
2. opportunistic;
3. pathogenic.

Among all representatives, there are anaerobes and aerobes. Their difference from each other lies in the peculiarities of existence and life. Aerobes are microorganisms that can live and multiply only under conditions of constant oxygen access. Representatives of another group are divided into 2 types: obligate (strict) and facultative (conditional) anaerobes. Both those and others receive energy for their existence in the absence of oxygen. For obligate anaerobes, it is fatal, but not for facultative anaerobes, that is, microorganisms can exist in its presence.

Normal microorganisms

These include gram-positive (bifidobacteria, lactobacilli, eubacteria, peptostreptococci) and gram-negative (bacteroids, fusobacteria, veilonella) anaerobes. This name is associated with the surname of the Danish bacteriologist - Gram. He developed a special method for staining smears using aniline dye, iodine and alcohol. On microscopy, some of the bacteria have a blue-violet color and are gram-positive. Other microorganisms are discolored. For better visualization of these bacteria, a contrast dye (fuchsin) is used, which stains them pink. These are gram-negative microorganisms.

All members of this group are strict anaerobes. They form the basis of the entire intestinal microflora (92-95%). Beneficial bacteria produce antibiotic-like substances that help drive out dangerous infectious agents from the habitat. Also, normal microorganisms create a zone of "acidification" (pH = 4.0-5.0) inside the intestine and form a protective film on the surface of its mucous membrane. Thus, a barrier is formed that prevents the colonization of foreign bacteria from outside. Beneficial microorganisms regulate the balance of opportunistic flora, preventing its overgrowth. Participate in the synthesis of vitamins.

These include gram-positive (clostridia, staphylococci, streptococci, bacilli) and gram-negative (Escherichia - Escherichia coli and other representatives of the Enterobacteriaceae family: Proteus, Klebsiella, Enterobacter, Citrobacter, etc.) optional anaerobes.

These microorganisms are opportunistic. That is, with well-being in the body, their effect is only positive, like that of normal microflora. The impact of unfavorable factors leads to their excessive reproduction and transformation into pathogens. It develops with diarrhea, a change in the nature of the stool (liquid with an admixture of mucus, blood or pus) and a deterioration in general well-being. The quantitative growth of opportunistic microflora can be associated with a weakened immune system, inflammatory diseases of the digestive system, malnutrition and the use of drugs (antibiotics, hormones, cytostatics, analgesics and other drugs).

The main representative of enterobacteria is with typical biological properties. She is able to activate the synthesis of immunoglobulins. Specific proteins interact with pathogenic microorganisms from the enterobacteriaceae family and prevent their penetration into the mucous membrane. In addition, E. coli produces substances - colicins with antibacterial activity. That is, normal Escherichia is able to inhibit the growth and reproduction of putrefactive and pathogenic microorganisms from the family of enterobacteria - Escherichia coli with altered biological properties (hemolyzing strains), Klebsiella, Proteus and others. Escherichia take part in the synthesis of vitamin K.

Opportunistic microflora also includes yeast-like fungi of the genus Candida. They are rarely found in healthy children and adults. Their detection in feces, even in small quantities, should be accompanied by a clinical examination of the patient in order to exclude (excessive growth and reproduction of yeast-like fungi). This is especially true in young children and patients with reduced immunity.

Pathogenic microorganisms

These are bacteria that enter the digestive tract from the outside and cause acute intestinal infections. Infection with pathogenic microorganisms can occur when eating contaminated food (vegetables, fruits, etc.) and water, in violation of the rules of personal hygiene and contact with a patient. Normally, they are not found in the intestines. These include pathogenic agents of dangerous infections - pseudotuberculosis and other diseases. The most frequent representatives of this group are Shigella, Salmonella, Yersinia, etc. Some pathogens (Staphylococcus aureus, Pseudomonas aeruginosa, atypical E. coli) can be found among medical personnel (carriers of the pathogenic strain) and in hospitals. They cause serious hospital infections.

All pathogenic bacteria provoke the development of intestinal inflammation by type or with stool disorder (diarrhea, mucus in the feces, blood, pus) and the development of intoxication of the body. The beneficial microflora is suppressed.

The norms of the content of bacteria in the intestine

Beneficial bacteria

Normal microorganisms			Children over 1 year old	Adults
Bifidobacteria	10 9 –10 10	10 8 –10 10	10 10 –10 11	10 9 –10 10
Lactobacillus	10 6 –10 7	10 7 –10 8	10 7 –10 8	>10 9
Eubacteria	10 6 –10 7	>10 10	10 9 –10 10	10 9 –10 10
Pepto-streptococci	<10 5	>10 9	10 9 –10 10	10 9 –10 10
Bacteroids	10 7 –10 8	10 8 –10 9	10 9 –10 10	10 9 –10 10
Fusobacteria	<10 6	<10 6	10 8 –10 9	10 8 –10 9
Waylonella	<10 5	>10 8	10 5 –10 6	10 5 –10 6

CFU / g is the number of colony forming units of microbes in 1 gram of stool.

Conditionally pathogenic bacteria

Conditionally pathogenic microorganisms	Breastfed babies under 1 year old	Children under 1 year old on artificial feeding	Children over 1 year old	Adults
Escherichia coli with typical properties	10 7 –10 8	10 7 –10 8	10 7 –10 8	10 7 –10 8
Clostridia	10 5 –10 6	10 7 –10 8	< =10 5	10 6 –10 7
Staphylococci	10 4 –10 5	10 4 –10 5	<=10 4	10 3 –10 4
Streptococci	10 6 –10 7	10 8 –10 9	10 7 –10 8	10 7 –10 8
Bacilli	10 2 –10 3	10 8 –10 9	<10 4	<10 4
Mushrooms of the genus Candida	absent	absent	<10 4	<10 4

Beneficial gut bacteria

Gram-positive severe anaerobes:

Gram-negative severe anaerobes:

• Bacteroids- polymorphic (having different sizes and shapes) sticks. Together with bifidobacteria, they colonize the intestines of newborns by 6-7 days of life. When breastfeeding, bacteroids are detected in 50% of children. With artificial feeding, they are sown in most cases. Bacteroids are involved in digestion and the breakdown of bile acids.
• Fusobacteria- polymorphic rod-shaped microorganisms. Typical for the intestinal microflora of adults. Often they are sown from pathological material with purulent complications of various localization. They are able to secrete leukotoxin (a biological substance with a toxic effect on leukocytes) and a platelet aggregation factor responsible for thromboembolism in severe septicemia.
• Waylonella- coccal microorganisms. In children who are breastfed, they are detected in less than 50% of cases. In infants on artificial nutrition, mixtures are sown in high concentration. Veilonella are capable of great gas production. With their excessive reproduction, this distinctive feature can lead to dyspeptic disorders (flatulence, belching and diarrhea).

How to check the normal microflora?

A bacteriological study of feces should be carried out by inoculation on special nutrient media. The material is taken from the last portion of feces with a sterile spatula. The required amount of feces is 20 grams. The material for research is placed in a sterile container without preservatives. It is necessary to take into account the fact that microorganisms - anaerobes must be reliably protected from the action of oxygen from the moment of feces sampling to its sowing. It is recommended to use test tubes filled with a special gas mixture (carbon dioxide (5%) + hydrogen (10%) + nitrogen (85%)) and a tightly ground cap. No more than 2 hours should pass from the moment of sampling the material to the start of bacteriological research.

This analysis of feces allows you to detect a wide range of microorganisms, calculate their ratio and diagnose visible disorders - dysbiosis. Disturbances in the composition of the intestinal microflora are characterized by a decrease in the proportion of beneficial bacteria, an increase in the amount of conditionally pathogenic flora with a change in its normal biological properties, as well as the appearance of pathogens.

Low content of normal microflora - what to do?

The imbalance of microorganisms is corrected with the help of special preparations:

1. promote colonization of the intestine by the main microflora by selectively stimulating the growth and metabolic activity of one or more groups of bacteria. These drugs are not drugs. These include undigested food ingredients that serve as a substrate for beneficial bacteria and are not affected by digestive enzymes. Preparations: "Hilak Forte", "Duphalac" ("Normase"), "Calcium Pantothenate", "Lysozyme" and others.
2. – these are living microorganisms that normalize the balance of intestinal bacteria and compete with opportunistic flora. They have a beneficial effect on human health. They contain useful bifidobacteria, lactobacilli, lactic acid streptococcus, etc. Preparations: "Acylact", "Linex", "Bactisubtil", "Enterol", "Kolibacterin", "Lactobacterin", "Bifidumbacterin", "Bifmadikol " other.
3. Immunostimulating agents. They are used to maintain normal intestinal microbiocenosis and increase the body's defenses. Preparations: "KIP", "Immunal", "Echinacea", etc.
4. Medicines that regulate the transit of intestinal contents. Used to improve digestion and evacuation of food. Preparations:, vitamins, etc.

Thus, the normal microflora with its specific functions - protective, metabolic and immunostimulating - determines the microbial ecology of the digestive tract and participates in maintaining the constancy of the internal environment of the body (homeostasis).

The value of intestinal microflora

The most important role in the life of the human body is played by the intestinal microbiocenosis - symbiotic microorganisms that actively participate in the formation of the immunobiological reactivity of the body, in metabolism, in the synthesis of vitamins, essential amino acids and a number of biological compounds. Normal flora, showing antagonistic activity in relation to pathogenic and putrefactive microorganisms, is the most important factor preventing the development of infections.

Violation of the mobile balance of symbiotic microorganisms of normal microflora, which can be caused by massive and sometimes uncontrolled use of antibiotics and chemotherapeutic drugs, environmental or social ill-being (chronic stress), widespread human use of chemical products that enter the environment, the so-called xenobiotics, increased radiation background and malnutrition (the use of refined and canned food) is usually called dysbiosis, or dysbiosis. With dysbiosis, the state of dynamic balance between all its components (macro- and microorganism and the habitat) is disturbed and is designated as eubiotic. The state of dynamic balance between the host organism, the microorganisms that inhabit it, and the environment is commonly called "eubiosis", in which human health is at an optimal level.

Currently, the dominant idea of ​​the microflora of the human body as another "organ" covering the intestinal wall, other mucous membranes and human skin. The mass of normal microflora is about 5% of the mass of an adult (2.5–3.0 kg), and has about 1014 cells (one hundred billion) of microorganisms. This number is 10 times the number of cells in the host's body.

The main reservoir of microorganisms is the lower colon. The number of microbes in the large intestine reaches 1010-1011 per 1 g of intestinal contents, in the small intestine - their number is much less, due to bactericidal activity of gastric juice, peristalsis and, probably, endogenous antimicrobial factors of the small intestine, although it can reach 108 in humans.

In healthy individuals, about 95–99% of microbes amenable to cultivation are anaerobes, which are represented by bacteroids (105–1012 in 1 g of feces) and bifidobacteria (108–109 bacterial cells in 1 g of feces). The main representatives of the aerobic flora of feces are: E. coli (106-109), enterococcus (103-109), lactobacilli (up to 1010). In addition, staphylococci, streptococci, clostridia, klebsiella, proteus, yeast-like fungi, protozoa, etc. are detected in smaller quantities and less often.

Normal microflora, being symbiotic, performs a number of functions that are essential for the vital activity of a macroorganism, and is a nonspecific barrier - a biofilm, which, like a glove, lines the inner surface of the intestine and consists, in addition to microorganisms, of exopolysaccharides of various compositions, as well as mucin. Biofilm regulates the relationship between the microorganism and the environment.

Normal intestinal microflora has an important effect on the protective and metabolic-trophic adaptive mechanisms of the body:

- reducing the potential for pathogenic effects on the intestinal wall from pathogens;

- potentiation of the maturation of the mechanisms of general and local immunity;

- increasing the concentration of nonspecific factors of immunity and their antibacterial activity;

- the formation of a protective biolayer on the surface of the intestinal mucous membranes, "sealing" the intestinal wall and preventing the penetration of toxins of pathogens into the beds;

- the release of organic acids (lactic, acetic, formic, propionic, butyric), which contribute to the acidification of the chyme, preventing the reproduction of pathogenic and opportunistic bacteria in the intestine;

- various antibiotic substances synthesized by the intestinal autoflora (colicins, lactolin, streptocid, nisin, lysozyme, etc.) directly have a bactericidal or bacteriostatic effect on pathogens.

The normal intestinal microflora takes an active part in the digestion processes and in the biochemical processes of fat and pigment metabolism. The beneficial effect of intestinal microflora on the processes of absorption and metabolism, utilization of calcium, iron, vitamin D.

The natural intestinal microflora inhibits the decarboxylation of food histidine, thereby reducing the synthesis of histamine, and therefore, reduces the risk of food allergies in children. Thanks to the normal intestinal autoflora, the vitamin-synthesizing function of microorganisms is carried out, in particular vitamins C, K, B, B2, B6, B12, PP, folic and pantothenic acids, and the absorption of vitamins D and E, which entered the body with food, improves. An important role is played by the natural intestinal flora in the synthesis of essential amino acids for the body.

The entire intestinal microflora is divided into:

1) the obligate part, which includes microorganisms that are constantly part of the indigenous flora and play an important role in metabolic processes and the protection of the host organism from infection;

2) an optional part, which includes bacteria that are often found in healthy people, which can act as etiological factors of diseases in the event of a decrease in the resistance of the microorganism;

3) a transient part, the detection or identification of representatives of which is of a random nature, since they are incapable of a long stay in a macroorganism. In addition, pathogens of infectious diseases can periodically be present in the intestinal lumen of a healthy person in small quantities without causing the formation of a pathological syndrome as long as the host's defense systems prevent their excessive reproduction.

Difficulties often arise in the interpretation of the results of bacteriological examination of feces in connection with their wide fluctuations even in practically healthy people, the rapid change in indicators in the same patient during repeated studies without any regularity. In addition, it is known that the microflora of feces does not always reflect the content of the parietal, crypt and, probably, even the intraluminal (cavity) intestinal microflora.

Violation of intestinal microbiocenosis

Various adverse effects on humans lead to the formation of various pathological conditions and disorders, quantitative and qualitative changes in the normal intestinal microflora occur. However, if, after the disappearance of an unfavorable external factor, these changes spontaneously disappear, they can be attributed to the category of "dysbacterial reactions". The concept of "dysbacterium" of the intestine is broader, while the qualitative and quantitative changes in the normal intestinal microflora are more pronounced and persistent. Dysbacterium is considered as a manifestation of disharmony in the ecological system.

Dysbiosis, on the other hand, is a state of the ecosystem, in which the functioning of its constituent parts and interaction mechanisms occurs, as a result of which a human disease develops. Dysbiosis affects patients of almost all clinics and hospitals, residents of ecologically unfavorable regions, workers in hazardous industries. Disturbances of the normal microflora of these categories of the population are formed as a result of exposure to the body of physical, chemical, radiation and other factors. Poor nutrition, especially in winter, excessive use of refined foods, the annual transition from winter to summer form of nutrition and return to it can be attributed to the risk factors for dysbiosis.

The intestinal microflora is called dysbiotic only if pronounced and stable qualitative changes in it are accompanied by the appearance of a number of clinical symptoms of the disease.

Dysbacteriosis reflects the state of bacterial forms of microflora representatives. Dysbacteriosis is a condition characterized by a disturbance in the mobile balance of the intestinal microflora, which normally populates non-sterile cavities and skin, the occurrence of qualitative and quantitative changes in the intestinal microflora. According to OST 91500.11. 0004-2003 intestinal dysbiosis is considered as a clinical and laboratory syndrome that occurs in a number of diseases and clinical situations, characterized by changes in the qualitative and / or quantitative composition of normal microflora, metabolic and immune disorders, accompanied by clinical manifestations in some patients.

Dysbacteriosis is most often manifested by a decrease in the total number of microbes, sometimes to the complete disappearance of certain types of normal microflora with a simultaneous predominance of species that are normally present in minimal quantities. This predominance can be long-term or intermittently.

There are four microbiological phases in the development of intestinal dysbiosis. In the first (initial) phase, the number of normal symbionts in natural (usual) habitats sharply decreases. In the second phase, the number of some microorganisms sharply decreases (or the disappearance of some symbionts is observed) due to an increase in the number of others. The third phase is characterized by the fact that the localization of the autoflora changes, i.e. its appearance is observed in organs in which it usually does not occur. In the fourth phase, signs of pathogenicity appear in individual representatives or associations of the microbial flora. Intestinal dysbiosis can occur in latent (subclinical), local (local) and widespread (generalized) forms (stages). In the latent form, a change in the normal composition of symbionts in the intestine does not lead to the appearance of a visible pathological process. With a widespread form of dysbiosis, which can be accompanied by bacteremia, generalization of infection, due to a significant decrease in the general resistance of the body, a number of organs are affected, including parenchymal organs, intoxication increases, and sepsis often occurs. According to the degree of compensation, compensated (often latent), subcompensated (usually local) and decompensated (generalized) forms are distinguished.

Antagonistic relationships between representatives of natural associations play a significant role in the onset of dysbiosis. Small temporary fluctuations in the number of individual microorganisms are eliminated on their own, without any intervention. The causes of dysbiosis can be diseases that create conditions under which the rate of reproduction of some representatives of microbial associations increases or specific substances accumulate that suppress the growth of other microorganisms. These pathological conditions lead to significant changes in the composition of microflora and quantitative ratios of various microbes.

Most often, dysbiosis develops against the background of stomach diseases occurring with achlorhydria, chronic enteritis and colitis, chronic pancreatitis, liver and kidney diseases, B12-folate deficiency anemia, malignant neoplasms, resection of the stomach and small intestine, peristalsis disorders, in particular, colon stasis.

Dysfunction of the small and large intestine can lead to diarrhea, in the pathogenesis of which an increase in osmotic pressure in the intestinal cavity, disturbance of absorption processes and intestinal hypersecretion, impaired passage of intestinal contents, intestinal hyperexudation play a significant role. Most forms of diarrhea associated with damage to the small and large intestine are characterized by a significant increase in the concentration of electrolytes in the feces, which reaches their content in the blood plasma. However, in case of impaired absorption of lactase in the pathogenesis of diarrhea, the osmotic component predominates, when the loss of water exceeds the loss of salt.

In patients suffering from chronic diseases of the liver, gallbladder and pancreas, as well as in those who have undergone extensive resection of the ileum, the process of fat absorption is impaired. In this case, fatty and bile acids stimulate the secretory function of the colon by activating intestinal adenylate cyclase and increasing the permeability of the mucous membrane, which leads to the development of diarrhea in patients with this pathology.

In chronic conditions, a disorder of the absorption process in the intestine is caused by dystrophic, atrophic and sclerotic changes in the epithelium and intestinal mucosa. At the same time, the villi and crypts are shortened and flattened, the number of microvilli decreases, fibrous tissue grows in the intestinal wall, blood and lymph circulation is disturbed. A decrease in the total suction surface and absorption capacity leads to disruption of intestinal absorption processes. This pathological process in the small intestine, which occurs in chronic diseases of the gastrointestinal tract, is characterized by thinning of the intestinal mucosa, loss of brush border disaccharidases, impaired absorption of mono- and disaccharides, a decrease in the digestion and absorption of proteins, an increase in the time of transport of contents through the intestine, colonization of bacteria in the upper parts of the small intestine.

Insufficiently balanced nutrition has recently been the cause of diseases of the small intestine, in which metabolic processes are disturbed and dysbiosis develops. As a result, the body receives an insufficient amount of products of hydrolysis of proteins, fats, carbohydrates, as well as mineral salts and vitamins. A picture of the pathological process in the small intestine due to protein deficiency develops, resembling that in bowel diseases. The reason for the development of dysbiosis in patients is rheumatic diseases, which are based on systemic or local damage to the connective tissue. The defeat of the intestine in systemic diseases of the connective tissue is determined by atrophy of muscle fibers, their replacement with fibrous connective tissue, infiltration of the muscle layer of the intestinal wall with lymphoid elements. Changes in blood vessels are also characteristic: arteritis, proliferation of the intima of arteries of medium and small caliber with a pronounced narrowing of their lumen. The submucosal and muscular layers of the intestinal wall are most often affected. As a result of these changes, disorders of the motor, absorption and digestive functions of the intestine occur. The resulting disorders of motor function, lymph formation and blood supply to the intestinal wall lead to stasis of the intestinal contents, the development of a syndrome of impaired absorption and the growth of pathogenic and opportunistic flora with its imbalance.

The onset of dysbiosis is facilitated by the unjustified and unsystematic use of antibiotics and other antibacterial drugs that destroy normal symbionts and lead to the reproduction of flora resistant to them, as well as allergic reactions, including those caused by the sensitization of the microorganism by microbial strains that have become resistant to these agents.

Thus, in the pathogenesis of the disease, damage to the intestinal mucosa as a result of prolonged exposure to mechanical, toxic, allergic factors is essential. The intestinal nervous apparatus is involved in the pathological process, which leads to disruption of the motor and secretory functions of the intestine. Dysbacteriosis develops, characterized by a decrease in the number of microorganisms constantly present in the intestine (bifidobacteria, Escherichia coli, lactobacilli), a violation of the ratio of bacteria in different parts of the intestine, increased reproduction of conditionally pathogenic and the appearance of pathogenic flora. With a sharp weakening of immunity, these microbes are capable of causing localized pyoinflammatory and generalized processes.

Active intervention in the course of most diseases with chemotherapy, provided that there are many diseases occurring at the same time - polymorbidity very often leads to a violation of the microbiocenosis. For example, it is known that etiotropic therapy of acute and chronic gastrointestinal diseases, especially quadritis therapy of chronic gastritis, gastric ulcer and duodenal ulcer associated with Helicobacter pylori, in 100% of cases leads to aggravation of dysbiotic phenomena.

Normal intestinal microflora

Representatives of normal human intestinal microflora are:

1. Gram-positive obligate-anaerobic bacteria:

Bifidobacteria - gram-positive bacilli, strict anaerobes, representatives of obligate microflora, present in the intestine throughout the life of a healthy person, with high antagonistic activity against pathogenic microorganisms, prevent the penetration of microbes into the upper gastrointestinal tract and other internal organs, have a pronounced immunostimulating action on the local immunity system of the intestine;

Lactobacilli are gram-positive bacteria, microaerophiles. They belong to the obligate intestinal flora, suppress putrefactive and pyogenic bacteria, due to antibacterial activity they protect the intestinal mucosa from the possible introduction of pathogenic microbes;

Eubacteria - gram-positive non-spore-forming polymorphic rod-shaped bacteria, strict anaerobes, are involved in the transformation of cholesterol into coprostanol and in the deconjugation of bile acids;

Peptostreptococci - gram-positive cocci, strict anaerobes, belong to the obligate intestinal microflora, can become an etiological factor of various infections;

Clostridia - gram-positive spore-forming, often motile, rod-shaped bacteria, strict anaerobes, belong to the facultative part of the normal intestinal microflora, are involved in the deconjugation of bile acids, many lecithin-negative clostridia are involved in maintaining colonization resistance, suppressing the reproduction in the intestine, some pathogenic clostridia are capable of proliferating to give toxic metabolic products, which, with a decrease in the body's resistance, can cause endogenous infection.

2. Gram-negative obligate anaerobic bacteria:

Bacteroids - non-spore-forming polymorphic rods, strict anaerobes, take part in digestion and in the breakdown of bile acids, are able to secrete hyaluronidase, heparinase, neurominase, fibrinolysin and _-lactamase and synthesize enterotoxin;

Fusobacteria - non-spore-forming polymorphic rod-shaped bacteria, strict anaerobes, possess hemagglutinins, hemolysins, are able to secrete leukotoxin and platelet aggregation factor responsible for thromboembolitis in severe septicemia;

Veilonella - obligate-anaerobic cocci, weakly fermenting sugars and capable of reducing nitrate and gas production, which, if excessively multiplied in the intestine, can cause dyspeptic disorders.

3. Facultative anaerobic microorganisms:

Escherichia - gram-negative mobile rods, opportunistic microorganisms belonging to the Enterobactericae family, can produce colicins that inhibit the growth of enteropathogenic strains of this type of bacteria and maintain the local immunity system in a physiologically active state, take part in vitamin formation;

Staphylococci - gram-positive cocci belonging to the Micrococcaceae family, are present in the intestine in small concentrations, have pathogenic properties, do not cause the formation of pathological processes until the resistance of the macroorganism decreases as a result of any adverse effects;

Streptococci - gram-positive cocci, are part of the facultative microflora, acidify the fermentation habitat of carbohydrates, participate in maintaining colonization resistance at an optimal level;

Bacilli are gram-positive rod-shaped spore-forming bacteria, their main ecological niche is soil; when they enter the intestine in high concentrations, bacilli can cause foodborne toxic infections;

Yeast-like fungi of the genus Candida are rarely found in small concentrations in stool.

Dosage regimen of the drug

LINEX (combination drug)

Apply after meals.

For infants and children under 2 years of age: 3 times a day, 1 capsule (the contents of the capsule can be diluted in milk or water).

For children from 2 to 12 years old: 3 times a day, 1 or 2 capsules with a small amount of liquid.

For adults: 3 times a day, 2 capsules with a small amount of liquid.

The duration of treatment depends on the cause of the development of dysbiosis.

Provides a summary of the manufacturer's information on dosage of the medicinal product.

Funds. Read the instructions carefully before prescribing the drug.

Correction of disturbed microflora of the gastrointestinal tract

The need to stabilize or correct the disturbed normal microflora of the gastrointestinal tract is beyond doubt. To stabilize normal microflora, various drugs are used, which are usually subdivided into probiotics, prebiotics and synbiotics.

Prebiotics have a positive effect on the intestinal microflora, contributing to the normalization of the internal intestinal environment, which worsens the conditions for the development of pathogenic and opportunistic microorganisms, but are only auxiliary. Currently, the most common means of maintaining the human microbiocenosis at an optimal level and correcting it are probiotics.

For the first time, the term "probiotic" was proposed in 1965 as the antonym of an antibiotic to denote microbial metabolites that have the ability to stimulate the growth of microorganisms. Probiotics are substances of microbial or non-microbial origin that, when administered naturally, have beneficial effects on the physiological and biochemical functions of the host organism through the optimization of its microecological status. This definition assumes that any living or killed microorganisms, their structural components, metabolites, as well as substances of other origin that have a positive effect on the functioning of the host microflora, contributing to better adaptation of the host to the environment in a specific ecological niche, can be considered as probiotics.

Domestic researchers, along with the term "probiotics", widely use the term "eubiotics" as its synonym. Most often, this term denotes bacterial preparations from living microorganisms intended for the correction of the host microflora. However, in essence, eubiotics, according to modern representatives, should be considered as a frequent variety of probiotics, and the term "eubiotic" itself is not used in foreign special literature

The following main groups of probiotics are distinguished:

Preparations containing live microorganisms (monocultures or their complexes);

Preparations containing structural components of microorganisms - representatives of normal microflora or their metabolites;

Preparations of microbial or other origin, stimulating the growth and activity of microorganisms - representatives of normal microflora;

Preparations based on live genetically engineered strains of microorganisms, their structural components and metabolites with specified characteristics;

Functional food products based on living microorganisms, their metabolites, and other compounds of microbial, plant or animal origin, capable of maintaining and restoring health through the correction of the microbiocenosis of the host organism.

The positive effect of probiotics based on living microorganisms on the host organism is realized through the normalization of microbiocenosis due to: inhibition of the growth of potentially harmful microorganisms as a result of the production of antimicrobial substances; competition with them for adhesion receptors and nutrients; activation of immunocomponent cells; stimulating the growth of representatives of the indigenous flora as a result of the production of vitamins and other growth-stimulating factors, normalizing pH, neutralizing toxins; changes in microbial metabolism, manifested in an increase or decrease in enzyme activity. Probiotics based on components of microbial cells or metabolites realize their positive effect on physiological functions and biochemical reactions, either by directly interfering with the metabolic activity of cells of the corresponding organs and tissues, or indirectly through the regulation of the functioning of biofilms on mucous macroorganisms.

The effectiveness of probiotics depends on many factors: their composition, the state of the microbial ecology of the host, the age, sex and species of the latter, the conditions of his residence, etc.

The following types of microorganisms are most often used for the manufacture of probiotics: Bacillus subtilis, Bifidobacterium adolescentis, B. bifidum, B. breve, B. longum; Enterococcus faecalis, E. faecium; Escherichia coli; LactoBacillus acidophilus, L. casei, L. delbrueckii subsp. bulgaricus, L. Helveticus, L. fermentum, L. lactis, L. salivarius, L. plantarum; Lactococcus spp., Leuconostoc spp., Pediococcus spp., Propionibacterium acnes; Streptococcus cremoris, S. lactis, S. salivarius subsp. thermophilus.

Among probiotics, bifid-containing drugs play a special role: bifidumbacterin, bifidumbacterin forte, probifor. The active principle of these drugs are live bifidobacteria, which have antagonistic activity against a wide range of pathogenic and opportunistic bacteria, the main purpose is to ensure the rapid normalization of the microflora of the intestinal and urogenital tracts. Bifid-containing, monocomponent drugs are used to normalize the microbiocenosis of the gastrointestinal tract, increase the body's nonspecific resistance, stimulate the functional activity of the digestive system, and prevent hospital infections in maternity hospitals and hospitals.

In addition to monocomponent drugs, drugs with a combination of microorganisms are extremely widespread: bificol (bifidocolibacteria), bifiform (bifidum-enterococcus), biphocyte (bifidum-lactobacillus), fermented milk bifylact, linex (mixture of lacto-, bifidobacteria and St. Facium).

For example Linex is a combined preparation containing 3 components of natural microflora from different parts of the intestine. The bifidobacteria, lactobacilli and nontoxigenic lactic acid group D streptococcus, which are part of Linex, maintain and regulate the physiological balance of the intestinal microflora (microbiocenosis) and ensure its physiological functions (antimicrobial, vitamin, digestive) in all parts of the intestine - from the small intestine to the rectum. Lactobacillus and lactic acid streptococcus are more often found in the small intestine, and bifidobacteria - in the large intestine. Once in the intestine, Linex components perform all the functions of their own normal intestinal microflora:

Create unfavorable conditions for the reproduction and vital activity of pathogenic microorganisms,

Participate in the synthesis of vitamins B1, B2, B3, PP, folic acid, vitamins K and E, ascorbic acid, normal microflora fully meets human needs for vitamins B6 and H (biotin); vitamin B12 in nature is synthesized only by microorganisms,

By producing lactic acid and lowering the pH of intestinal contents, they create favorable conditions for the absorption of iron, calcium, vitamin D,

Lactic acid microorganisms inhabiting the small intestine carry out the enzymatic breakdown of proteins, fats and complex carbohydrates (including with lactase deficiency in children), proteins and carbohydrates not absorbed in the small intestine undergo deeper breakdown in the large intestine by anaerobes (including bacteria ),

Allocate enzymes that facilitate the digestion of proteins in infants (phosphoprotein-phosphatase of bifidobacteria is involved in the metabolism of milk casein),

Participate in the metabolism of bile acids (the formation of stercobilin, coprosterol, deoxycholic and lithocholic acids; promote the reabsorption of bile acids).

The therapeutic effect is associated with a wide range of antagonistic activity of each of the cultures included in the probiotic, which suppress the growth and development of pathogenic and opportunistic microorganisms.

Linex is most effective for acute intestinal infections of a viral and bacterial nature, chronic diseases of the gastrointestinal tract, occurring with symptoms of intestinal dysbiosis. In severe cases, it is shown to be combined with chemotherapy and antibiotic therapy, taking into account the spectrum of antibiotic resistance of probiotic cultures.

To a lesser extent, complex preparations are used: bifidumbacterin-forte (with stone sorbent), bifilis (with lysozyme), nutrolin B (with B vitamins), kipatsid (with immunoglobulin), recombinant drugs (subalin).

Most of the known probiotics are used in medical practice in the form of powders, tablets, suspensions, pastes, creams, suppositories, and sprays.

However, the most effective were the encapsulated forms of probiotics, the capsule is acid-resistant, i.e. does not dissolve with hydrochloric acid and pepsin, which ensures the release in the intestine of high concentrations of bacteria contained in the preparation practically without their inactivation at the level of the stomach.

Probiotic drugs are the most physiological and effective in the treatment and prevention of intestinal dysbiosis, but their appointment requires a differentiated approach, which takes into account not only microecological indicators, but also the degree of the organism's compensatory capabilities. On average, the course of treatment with probiotics is 2–4 weeks under the control of microflora indicators. It is advisable to prescribe probiotic preparations taking into account microbiological disorders, the phase and stage of intestinal dysbiosis, as well as the state and nature of the underlying disease. It should be noted that the experience of the differentiated use of probiotic drugs for various dysfunctions of the gastrointestinal tract indisputably testifies to their clear clinical and microbiological effect and the need for wider implementation in clinical practice.

Intestinal microflora Is a collection of non-pathogenic microorganisms that live in the intestines of a healthy person. Human organisms and bacteria coexist in a mutually beneficial cooperation - symbiosis. The flora in the intestine appears in infancy and is preserved throughout a person's life.

Intestinal flora

Microorganisms in the human intestine

	Normal	Conditionally pathogenic	Pathogenic
Name of bacteria	Propionibacteria; Peptostreptococci; Bacteroids; Escherichia;	Proteus; Enterobacteriaceae; Citrobacters; Acinetobacters; Pseudomonas; Serration; Fusobacteria; Yeast and yeast-like fungi.	Shigella; Salmonella; Yersinia; Cholera vibrio.

Violation of intestinal microflora

Changes in the composition of the intestinal microflora can have serious consequences.

It can be associated both with the penetration of pathogenic microorganisms, which are not normally found in the digestive system, and with a decrease in the content of normal microflora -.

Causes

Symptoms

The symptomatology of dysbiosis depends on the severity of the disorders and the presence of concomitant diseases.

• ... The patient has flatulence, belching, diarrhea or constipation may appear. Patients constantly experience an unpleasant taste in their mouth.
• ... Many patients note the appearance of food allergies to those products that were previously tolerated normally. This manifestation is most typical for children. Allergy can be expressed as skin symptoms (itching, hives, edema) and intestinal symptoms. These include sharp pains in the lower abdomen, nausea, vomiting, and loose stools with foam.
• Impaired absorption. With the prolonged presence of dysbiosis, this leads to a change in the entire metabolism - the occurrence of energy deficiency, hypovitaminosis. The condition is usually accompanied by anemia, calcium deficiency, and other ionic disturbances.
• Intoxication. It is characterized by the onset of weakness, headache, a slight increase in temperature.

How to check the intestinal microflora?

To assess the state of the intestinal microflora, the patient is carried out. For this, either scraping or aspirate from the intestine is taken. The resulting material is sent for bacteriological examination. In the laboratory, bacteria are inoculated on nutrient media. By the grown colonies of microorganisms, one can judge the state of the intestinal flora. This study is an accurate way to diagnose her disorders.

Indirectly, the presence of dysbiosis can be evidenced by research methods that are aimed at detecting changes in the composition of feces. These include the biochemical study of feces. Such diagnostics makes it possible to detect characteristic chemical changes that indicate the presence of certain microorganisms in the intestine.

Prevention and treatment of microflora disorders

Nutrition

First of all, it involves the preparation of a balanced diet. It must include fermented milk products containing. Food should contain enough natural vitamins. At the risk of seasonal hypovitaminosis, it is recommended to additionally use multivitamin complexes.

Destruction of pathogenic bacteria

To eliminate pathogens from the intestines, special antibacterial drugs with selective effects are used. They do not affect the state of normal microflora, but they destroy harmful bacteria. This group includes nonabsorbable antibiotics (eg nifuroxazide) and (rifaximin).

Restoration of normal microflora

For drugs used from several groups:

• include live cultures of microorganisms that are normally found in the human intestine.
• Medicines from the group include all the necessary substances for the “beneficial” bacteria to multiply rapidly.
• Both those and other components are part of the combined funds -.

Restoration of immunity

Normalization of local immunity helps to maintain a constant composition of the intestinal flora. For this purpose, the patient is prescribed drugs with immunomodulatory effects - echinacea-based drugs, nucleic acids.

Catad_tema Gastrointestinal diseases in children - articles

Violation of intestinal microbiocenosis in children

Interview with a researcher of the scientific advisory department of the clinic of the Research Institute of Nutrition of the Russian Academy of Medical Sciences, Ph.D. Natalia Nikolaevna Taran

Natalia Nikolaevna, the term "dysbiosis" is very ambiguous. Neither foreign nor Russian classifications of diseases have such a disease. Nevertheless, you can constantly hear it from doctors and parents. Please explain what it is - intestinal dysbiosis.

Indeed, this condition is not an independent disease and a nosological unit. During the life of a person, in particular a child, various external and internal factors can cause changes in the intestinal microbiocenosis, but in most cases these deviations are of a transient nature and do not require correction. In the body of an adult, microflora in quantitative terms is 2-3 kg of body weight! And intestinal dysbiosis is a persistent qualitative and quantitative deviation in the composition of the intestinal microflora. It is necessary to know and remember that dysbiosis is always secondary.

What circumstances can cause intestinal microflora disorders?

There are a lot of these reasons, they differ slightly in different age groups. So, in infants, young children, the qualitative and quantitative composition of microflora can be influenced by the pathological course of pregnancy, childbirth by caesarean section, late breastfeeding, early artificial feeding, frequent respiratory and intestinal infections, food allergies, and the use of antibacterial agents. In older children, in addition to those already listed, factors such as unbalanced nutrition, chronic diseases of the digestive tract, stress, immunodeficiency, etc. are important.

Often, minor deviations in the state of the child's health become a reason for passing an analysis for dysbiosis. Natalia Nikolaevna, please list the situations when this analysis can really be shown.

The following situations may become the basis for a doctor's recommendation to conduct this study in addition to the main examination:

• long-term intestinal disorders that cannot be corrected;
• unstable stool (from diarrhea to constipation);
• the presence of mucus, blood, pieces of undigested food in the feces, uneven color;
• atopic dermatitis with elements of secondary infection;
• frequent acute respiratory viral infections;
• antibiotic therapy;
• drug therapy with hormones and immunosuppressants;
• long hospital stay.

Natalia Nikolaevna, how to approach the interpretation of the results obtained?

On the one hand, there is a classification of dysbacteriosis, which takes into account the number and ratio of "useful" (lacto-, bifido-) bacteria, Escherichia coli, opportunistic microorganisms. Normally, the content of bifidobacteria should be at least 10 9 -10 10, lactobacilli -10 6 - 10 8 living microbial bodies per 1 g of feces, and Escherichia coli should be about 0.01% of the total number of dominant bifidobacteria and lactobacilli. The optional part of the normal microflora (aureus and epidermal staphylococci, bacteria of the Enterobacteriaceae family - Proteus, Klebsiella, Clostridia, Enterobacter; some types of yeast fungi) should be no more than 0.6% of the total number of microorganisms.

1st degree dysbiosis is characterized by a decrease in the number of bifidobacteria and / or lactobacilli to a level of less than 10 6 CFU / g of feces and an increase in the number of E. coli more than 10 8 CFU / g of feces.

At 2nd degree- one type of opportunistic microorganisms 10 5 CFU / g of feces and associations of opportunistic microorganisms 10 3 -10 4 CFU / g of feces are detected.

3rd degree- identification of one type of opportunistic microorganisms or associations in high titers.

On the other hand, the interpretation of the microbiological analysis of feces and, accordingly, the need for its correction should be approached with great caution and practical conclusions should be drawn only after comparing the analysis data with the clinical picture and complaints of the patient or his parents.

What else should a pediatrician take into account when deciding on the treatment of intestinal microbiocenosis disorders?

It is important to understand that with dysbiosis, the normal intestinal flora does not die, only its quantity and ratio with opportunistic microorganisms decreases, and the medium of the colon chyme is alkalized. The uncontrolled use of anti bacterial drugs, phages, probiotics for the treatment of dysbiosis can lead to the opposite result - the aggravation of existing changes. This is especially true for young children.

What would you advise to use to correct dysbiosis in a child?

First, breast milk is the most effective preventive and curative "remedy" for infants. It contains substances that stimulate the growth of beneficial bacteria in the intestine, as well as the bifidobacteria and lactobacilli themselves.This contributes to a more efficient and high-quality formation of microbiocenosis and is fundamental for the development and formation of the child's immune system. In some cases, in young children, breastfeeding will be sufficient to successfully resolve temporary problems.

Secondly, the treatment of dysbiosis should always be comprehensive, taking into account the underlying disease and predisposing factors, the nature of the symptoms and the depth of the disorders, and also be carried out under the supervision of a physician.

For the treatment of dysbiosis, pro- and prebiotics are most actively used Probiotics - preparations containing live bacteria - representatives of the normal human intestinal microflora. Prebiotics, unlike probiotics, do not contain live bacteria, but at the same time have the property of favorably influencing the state of the microbiocenosis, improving the vital activity of beneficial bacteria and creating the most comfortable conditions for them. In some cases, the use of a prebiotic is sufficient to restore the harmonious balance of microflora.

Natalia Nikolaevna, what prebiotic would you recommend for use in children of different age groups?

One of the drugs with prebiotic properties is Hilak forte. Khilak forte contains an optimized set of metabolic activity products of lactobacilli strains and normal intestinal microorganisms, as well as lactic and phosphoric acids, amino acids. The biological activity of 1 ml of the drug Hilak forte corresponds to the activity of approximately 100 billion (10 10 -10 11) living microorganisms.

This combined and unique in its composition and functions, the drug is used in pediatric practice from birth (including in premature infants). After ingestion, it acts only in the intestinal lumen, is not absorbed into the bloodstream and is excreted from the digestive tract with feces.

• in complex therapy for nursing premature newborns both in the hospital and during the first 12 months of life:
• babies with unstable stools;
• bottle-fed infants. Khilak forte helps to soften the consistency of the stool, normalizes intestinal motility, disrupts the growth of putrefactive microflora;
• children of the first year of life with severe motility disorders, dysfunctional disorders of the gastrointestinal tract (GIT) - regurgitation and intestinal colic;
• children and adults from the first day of antibiotic therapy, acute intestinal infections, in chronic diseases of the gastrointestinal tract, which are accompanied by an imbalance in the intestinal microflora;
• with functional constipation.

The positive effect of the drug Hilak forte in the complex therapy of acute respiratory viral infections was also noted.

How is Khilak forte appointed?

Hilak forte is prescribed for babies in 15-30 drops, for children for 20-40 drops, for adults for 40-60 drops 3 times a day. After improvement of the condition, the initial dose of the drug can be reduced by half. It is taken orally before or during a meal in a small amount of liquid, except milk.

It is produced in a convenient dosage form that provides ease of dosing, depending on the age of the child.

Natalia Nikolaevna, thank you for the conversation!

Determine the meaning of the words,
and you will rid the light of half of its delusions.
Descartes

The aphorism in the epigraph of this article reflects the state of the problem of dysbiosis in the best possible way, since there are still many questions. Doctors often use the terms "dysbiosis", "dysbiosis", "intestinal microecology", "intestinal microbiocenosis" as synonyms, which, in strictly scientific terms, are not equivalent. The fundamental question is not even in the terms used, but in understanding the essence of the problem and its general biological significance. His solution will make it possible to more reasonably and purposefully carry out therapy aimed at correcting microbiocenosis.

General understanding of the normal microbiocenosis of the gastrointestinal tract

The gastrointestinal tract is one of the most complex microecological environments of the human body, in which, on the total area of ​​the mucous membrane, which is about 400 m 2, there is an extremely high and diverse (over 500 species) density of microbial contamination, in which the interaction between the protective systems of the macroorganism is very delicately balanced and microbial associations. It is believed that bacteria make up 35 to 50% of the volume of the human colon, and their total biomass in the gastrointestinal tract is close to 1.5 kg.

However, bacteria are unevenly distributed in the digestive tract. If in the stomach the density of microbial colonization is low and is only about 103-104 CFU / ml, and in the ileum - 107-108 CFU / ml, then in the area of ​​the ileocecal valve in the colon, the density gradient of bacteria reaches 1011-1012 CFU / ml. Despite such a wide variety of bacterial species inhabiting the gastrointestinal tract, most can be identified only molecularly and genetically.

Among commensal bacteria cultivated from the gastrointestinal tract, more than 99.9% are obligate anaerobes, of which the dominant representatives are: Bacteroides, Bifidobacterium, Eubacterium, Lactobacillus, Clostridium, Fusobacterium, Peptococcus, Peptostreptococcus, Escherichia and Veillonella... The composition of bacteria found in different parts of the gastrointestinal tract is highly variable. Depending on the frequency and constancy of the detection of bacteria, the entire microflora is divided into three groups ( ).

The individuality and stability of the microbiocenosis of the gastrointestinal tract under physiological conditions in humans is one of the characteristic features. The mechanisms of maintaining the stability of the qualitative and quantitative parameters of the indigenous microflora, despite the permanent intake of exogenous microorganisms with water and food, have not yet been fully elucidated. Among the leading factors providing such stability, natural natural defense systems are traditionally considered, which, among other things, provide nonspecific anti-infective resistance ( ).

Although the structural and functional significance of these systems in ensuring the stability of the microbiocenosis has not been studied equally, the available clinical observations clearly indicate that violations of their functional activity are naturally accompanied by a change in the composition of the flora. The influence of the normal acidity of gastric juice is especially great, providing a minimal entry of exogenous microorganisms into the small intestine.

In addition, the development of the concept of the microbial community (microbiota) implies the presence of regulatory influences between microorganisms, which allow them to participate in a coordinated manner in the processes occurring in certain biotopes (in particular, in the gastrointestinal tract). One of the key mechanisms of intercellular interaction between bacteria is the quorum sensing mechanism, which was first described in 1999, but in fact has not been studied at all in the indigenous microflora of the gastrointestinal tract.

Clinical aspects of gastrointestinal microbiocenosis disorders

Modern studies indicate that the obligate microflora of the gastrointestinal tract is directly involved in many vital processes of the macroorganism within the digestive tract itself, and also has numerous and varied systemic regulatory functions, due to which the indigenous microflora (normal microbiocenosis) of the intestine is often considered as an integral part of the macroorganism or as extracorporeal organ ( ).

Violation of the microbiocenosis of the gastrointestinal tract, characterized by a decrease in the qualitative and quantitative indicators of the obligate and facultative microflora, can also have a negative effect on human health. In addition to the "loss" of physiological functions associated with a decrease in the density of the presence of indigenous microflora, the development of dysbiosis can be associated with: a) translocation of bacteria and the development of endogenous infectious processes (up to purulent-septic conditions); b) with a decrease in the body's resistance; c) with the development of allergic and immunopathological conditions; d) the formation of pathogenic clones of bacteria, due to the abundance of plasmid and chromosomal genes in the intestinal lumen.

Principles of correction of dysbiotic disorders of the gastrointestinal tract

The problem of studying the microbiocenosis of the gastrointestinal tract is reduced to attempts to correct it using microbiological preparations. These attempts were made at the dawn of the study of this problem (L. G. Peretz), and are continuing with increasing intensity now. To date, extensive experience has been accumulated in the use of probiotics. They are usually used as prophylactic drugs and to correct dysbiotic disorders. However, there are many articles that describe their therapeutic effect in a number of pathological conditions.

Since the development of dysbiosis is not characterized by a banal deficiency of representatives of obligate and / or facultative microflora, but is an indicator indicating a violation of the microecosystem, the simple appointment of probiotics for the purpose of correcting microbiocenosis is clearly not enough. The main goal of the doctor should not be to "seeding" the intestinal mucosa of patients with normal microflora, but to restore the microbiocenosis of the gastrointestinal tract and the density of colonization of the indigenous microflora. Achieving this goal is possible:

• thanks to diet therapy;
• elimination of the action of exo- and endogenous factors that caused and maintains the violation of microbiocenosis (chronic inflammatory processes of various localization, lifestyle and dietary patterns, oncological diseases, etc.);
• restriction of colonization of the gastrointestinal mucosa by opportunistic microflora (selective decontamination);
• absorption and removal of toxic substances from the lumen of the gastrointestinal tract;
• restoration of the functional activity of the digestive tract (acidity of gastric juice, motor-evacuation activity of the intestine; optimization of the function of the hepatobiliary system, etc.);
• the appointment of biological products (pro-, pre- and synbiotics) that create and maintain optimal conditions that contribute to the restoration of microbiocenosis and provide replacement functions.

Prebiotics are chemical components (of microbial and non-microbial origin) that can selectively stimulate the growth and / or metabolic activity of one or more groups of bacteria that make up the normal indigenous microflora. Combined drugs, which include bacterial drugs and growth stimulants, are referred to as synbiotics.

According to modern concepts, strains used as probiotics must meet the following criteria: a) be safe for humans; b) be resistant to the acidic contents of the stomach, bile and pancreatic enzymes; c) have pronounced adhesive properties in relation to epithelial cells of the gastrointestinal mucosa; d) exhibit antimicrobial activity; e) inhibit the adhesion of pathogenic bacteria; f) be resistant to antibiotics; g) maintain stability during storage of the drug.

Most often, various types of lacto- and bifidobacteria are used as probiotics ( ).

Preference given to preparations containing lactic acid bacteria Lactobacillus spp... and Bifidobacterium spp., due to the fact that they are resistant to the action of gastric juice, bile and pancreatic enzymes, easily adhere and colonize the intestinal mucosa.

In order to increase the clinical efficacy of probiotics, at present, preference is given to the development and use of complex preparations, which include several strains of bifidobacteria and lactobacilli, vitamin complexes, pectins, which is believed to increase their adhesiveness and colonize the intestinal mucosa. Capsule forms also have certain advantages both in the stability of the drug and in maintaining the activity of the strain while passing through the acid barrier of the stomach.

These drugs include Linex, Bifikol, Atsilakt, Acipol, Bifistim, etc. The duration of the course of treatment with probiotics usually ranges from 2 weeks to 1-2 months. It is advisable to combine the intake of probiotics with the use of alkaline solutions (table mineral waters).

The clinical efficacy of probiotics is associated with the colonization of the intestinal mucosa and the replacement of the functions of normal indigenous intestinal microflora ( ), which ensures the creation of a microecological environment conducive to the restoration of indigenous microflora. Although the bacterial strains used in the production of probiotics are selected from the microflora of the human gastrointestinal tract, they still do not have long-term colonization resistance and are eliminated from the intestine within 3-7 weeks.

In recent years, Enterol, which contains the yeast Saccharomyces boulardii, has become widespread as probiotics. These yeasts are not part of the normal indigenous microflora of the gastrointestinal tract, however, they have pronounced antagonistic properties against a wide range of pathogenic and opportunistic bacteria, remain viable during transit through the gastrointestinal tract, are absolutely resistant to the action of any antibacterial drugs (sensitive only to antifungal drugs). The spectrum of their enzymatic activity, according to modern research, provides them with participation in the processes of digestion and metabolism. Saccharomyces boulardii are referred to as self-eliminating strains, since their elimination occurs within 3-4 days after stopping the drug intake. The usual course of treatment with Enterol is 7-10 days.

When restoring intestinal microbiocenosis, more and more attention is paid to a relatively new class of drugs - prebiotics, the most important requirement for which is the selectivity of action only on the indigenous microflora without enhancing the growth and reproduction of toxin-producing Clostridia, toxigenic strains of Escherichia coli and proteolytic bacteroids. The use of these drugs is possible only if bifidobacteria and lactobacilli dominate in the indigenous intestinal microflora.

The most commonly used prebiotics are Hilak forte and various fiber preparations (cornflakes, cereals, bread).

Hilak forte contains substrates of metabolic products of the indigenous intestinal microflora, which contribute to the regeneration of epithelial cells of the intestinal mucosa and the rapid restoration of normal flora. The drug is usually prescribed 40-60 drops 3 times a day in a small amount of liquid (with the exception of milk). Doses and duration of taking the drug are determined individually.

The clinical efficacy of combined preparations of probiotics and prebiotics (synbiotics) is still poorly understood due to insufficient experience.

Safety Considerations for Using Probiotics

Long-term experience with the clinical use of probiotics has contributed to the dissemination and strengthening of the opinion of their safety. However, clinical observations published in the medical press (especially in recent years) indicate the need for a deeper analysis of the safety issues of probiotics use.

It is currently believed that oral ingestion of live bacteria can theoretically be responsible for four types of side effects: a) the development of infectious processes caused by strains that make up probiotics; b) the development of metabolic disorders; c) excessive immunostimulation of the intestinal lymphatic apparatus; d) the formation of new clones of bacterial strains through the transfer of genes responsible for the expression of pathogenicity factors.

The greatest alertness is caused by the possibility of the development of infectious processes. Since the probiotic strains of bacteria were selected from among the representatives of the indigenous microflora, the risk of developing infectious processes is assessed as very low, but possible. This thesis is supported by a number of clinical observations and review articles, which describe cases of asymptomatic bacteremia, severe sepsis, endocarditis, pneumonia and abscesses caused by lacto-, bifido- or other bacteria. The entry of bacteria into the bloodstream is possible due to their translocation through the intestinal mucosa. Most common risk factors associated with bacteremia Lactobacillus are pathological processes of the gastrointestinal tract, causing a decrease in protective barrier functions that increase the permeability of the intestinal mucous membranes (gastrointestinal tumors, trauma, surgery) and immunosuppressive states.

Many authors note that bacteremia Lactobacillus it is very difficult to diagnose, since this type of bacteria is difficult to cultivate and identify, and in cases where they grow, it is often regarded as contamination. Most often, infectious processes were caused by Lactobacillus rhamnosus, Lactobacillus fermentum and Lactobacillus casei.

Enterococcus faecium and E. faecalis can also cause the development of infectious processes. In addition, there are already indications of the emergence of vancomycin-resistant strains of enterococci.

A certain concern is also caused by the widespread use of preparations containing yeast - Saccharomyces boulardii, which is associated with diagnosed fungemia. Most researchers note that the development of fungemia is due to exposure Saccharomyces boulardii on vascular catheters.

So, dysbiotic disorders of the gastrointestinal tract are an urgent problem of practical healthcare, requiring deep theoretical, experimental and clinical research. Despite the fact that the use of probiotics is an important part of the correction of microbiocenosis, it should not be an end in itself.

For literature questions, please contact the editorial office.

V. A. Malov, Doctor of Medical Sciences, Professor
N. M. Gyulazyan, Candidate of Medical Sciences
MMA them. I.M.Sechenova, Moscow