It belongs to the permanent microflora of the digestive tract. Intestinal microflora: causes of impairment and recovery methods
During normal functioning of the stomach, the microflora in it is almost absent, due to the acidic reaction of gastric juice and the high activity of hydrolytic enzymes. Therefore, in the stomach can be found in a small amount of acid-fast species - lactobacilli, yeast, Sarcinaventriculi and others (10 6 -10 7 cells per 1 ml of content).
In the duodenum and upper parts of the small intestine, there are few microorganisms, despite the fact that the acidic environment of the stomach is replaced by an alkaline one. This is due to the unfavorable effect on microbes of the enzymes present here. Enterococci, lactic acid bacteria, fungi, diphtheroids are found here (10 6 cells per 1 ml of contents). In the lower parts of the small intestine, gradually enriching, the microflora approaches the microflora of the large intestine.
The microflora of the colon is the most diverse in terms of the number of species (more than 200 species) and the number of detected microbes (10 9 -10 11 cells per 1 ml of content). Microbes make up 1/3 of the dry weight of feces.
Obligate microflora is represented by anaerobic (bacteroids, bifidumbacteria, veilonella) bacteria (96-99%) and facultative anaerobes (E. coli, enterococci, lactobacilli - 1-4%).
Transient microflora is represented by the following genera and species: Proteus, Klebsiella, Clostridia, Pseudomonas aeruginosa, Campylobacter, yeast-like fungi of the genus Candida, etc. Microorganisms of the genus Campylobacter (C. fennelliae, C. cinaedi, C. hyointestinalis) are found in the large intestine of human immunodeficiency ...
The composition of the intestinal microflora changes during a person's life.
In newborns, in the first hours after birth, meconium is sterile - aseptic phase. The second phase is the phase of increasing contamination (the first three days of a child's life). During this period, Escherichia, staphylococcus, enterococcus, yeast-like fungi predominate in the intestine. The third phase is the phase of transformation of the intestinal flora (starting from the 4th day of life). Lactic acid microflora, lactobacilli, acidophilic bacteria are established.
After the end of breastfeeding, a permanent biocenosis begins to form gradually in the digestive tract.
In the microflora of the gastrointestinal tract, mucosal (M) and luminal (P) microflora are distinguished, the composition of which is different. M-flora is closely associated with the mucous membrane, is more stable and is represented by bifidumbacteria and lactobacilli. M-flora prevents the penetration of the mucous membrane by pathogenic and opportunistic microorganisms. P-flora, along with bifidum and lactobacilli, includes other permanent inhabitants of the intestine.
To study the microflora of the large intestine, feces are examined, which are taken with a sterile wooden or glass rod and placed in a test tube with a preservative. The material is delivered to the laboratory within 1 hour, since with longer storage the relationships between species are significantly disrupted.
Microscopic examination of smears and feces stained according to Gram is carried out, as well as sowing of feces on nutrient media: Endo, blood agar, milk-salt agar, Sabouraud agar. Sowing is carried out in such a way that it is possible to count the number of colonies with different characteristics and determine the number of microbial cells of different types of microorganisms in a given sample. If necessary, biochemical identification and serological typing of species are carried out.
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Stages of formation of normal microflora of the gastrointestinal tract (GIT):
1) accidental seeding of the mucous membrane. Lactobacilli, clostridia, bifidobacteria, micrococci, staphylococci, enterococci, Escherichia coli, etc. enter the digestive tract;
2) the formation of a network of tape bacteria on the surface of the villi. Mainly rod-shaped bacteria are fixed on it, the process of biofilm formation is constantly going on.
Traditionally, it was believed that the bile duct is sterile, and the presence of microorganisms in the bile is a marker of the pathological process. This assumption was confirmed by the unsuccessful isolation of bacterial strains from the normal bile duct. However, modern researchers substantiate the phenomenon of “normal biliary tract microbiota” as a separate functional layer of the biliary tract wall, which protects the biliary tract from colonization by exogenous microorganisms. Thus, clinical methods of maintaining homeostasis of the ecosystem of normal biliary microbiota can be used to prevent hepatobiliary diseases and treat inflammatory diseases of the biliary tract.
Esophagus - normally contains no microorganisms.
Microflora of the stomach.The microflora of the stomach is usually poor due to the acidic environment of gastric juice, which is detrimental to many microorganisms. In the stomach - the habitat - extremely unpleasant - lactobacilli, yeast, single staphylococci and Here can be found sardines, spore-bearing rods, yeast. In the small intestine, the number of microbes is also small due to the bactericidal properties of its secretion. The large intestine is inhabited by an abundant microflora, represented by microbes of the intestinal group, enterococci and clostridia. There are also found anaerobic non-spore-forming rods, bacteroids, aerobic bacilli, spirilla, fungi and staphylococci, streptococci, lactic acid bacteria.
In the stomach, normally due to the acidic environment, the number of microbes is negligible (lactobacilli, streptococci, sarcins).
The intestine and the proximal part of the small intestine in healthy people are sterile due to the presence of aggressive digestive enzymes. In the distal part of the small intestine, 1 ml of contents contains 107-108 microbes, in equal numbers aerobic and anaerobic. 1 ml of the contents of the distal colon contains 109-1012 microbes of about 400 species. The highest density of contamination is observed in the rectum. The feces microfauna is actually the fauna of the distal colon.
In healthy people in the duodenum, the number of bacteria is not more than 10 in 4 - 10 in the 5th colony-forming units (CFU) per ml.
Intestinal microflora
- the concentration of microorganisms, their species composition and ratio varies depending on the intestinal section.
The human gut microflora consists of several hundred species, most of which are bacteria, such as E. coli. Other representatives of microflora are microscopic fungi, in particular yeast, as well as protozoa.
Gut bacteria are able to digest complex carbohydrates and other non-assimilable substrates, while producing vitamins, short-chain fatty acids (SCFA).
In order to study the functionality of the genes of the representatives of the human intestinal microflora, two consortia for the study of the human microbiota were organized: China) established a catalog of 3.3 million prevailing bacterial genes in the human intestinal metagenome.
In a newborn, in the first hours of life, the intestinal tract does not contain microbes. Then it is colonized by microorganisms that come with the mother's milk. In a healthy child, mainly lactic acid bacteria are found, which, after the termination of breastfeeding, are replaced by E. coli and enterococci.
A third of the feces that form in the large intestine are microbes.
Types of intestinal microflora
Parietal - constant in composition, performs the function of colonization resistance
The lumen is less constant in composition; it performs enzymatic and immunizing functions.
Bifidobacteria are the most significant representatives of obligate (obligatory) bacteria in the intestine. These are anaerobes, do not form spores, are gram-positive rods, the ends are bifurcated, and may have globular swellings. Most of the bifidobacteria are located in the large intestine, being its main parietal and luminal microflora. The content of bifidobacteria in adults is 10 in the 9th - 10 in the 10th CFU. on g.
Lactobacillus is another representative of the obligate microflora of the gastrointestinal tract and is lactobacillus. These are gram-positive rods, with pronounced polymorphism, located in chains or singly, do not form spores. Lactoflora can be found in human and animal milk. Lactobacillus (Lactobacillus). Content in the colon - 10 in the 6th - 10 in the 8th c.u. on g.
The representative of the obligate intestinal microflora is Escherichia (Escherichia Collie). - Escherichia coli. The content of Escherichia coli - 10 in the 7th - 10 in the 8th degree c.u. on g.
Eobiosis - microflora - normal flora. The biological balance of the normal flora is easily disturbed by factors of exogenous and endogenous nature.
Species composition - lactobacilli, bifidobacteria, bacteroids, enetrococci, yeast-like fungi, etc. With food intake, the number of bacteria can increase significantly, but in a short time, it returns to the initial level.
In the upper small intestine - the number of microorganisms - 10 in 4 -10 in 5 colony-forming units per ml, in the ileum up to 10 in the 8th degree.
Mechanisms that inhibit microbial growth in the small intestine.
Antibacterial action of bile
normal secretion of hydrochloric acid (prevents the growth of bacteria in the upper gastrointestinal tract);
ileocecal valve (prevents bacteria from entering the small intestine);
normal propulsive motility of the small intestine (prevents stagnation of intestinal contents).
Bifidobacteria and lactobacilli have pronounced antagonistic activity against pathogenic bacteria that regulate the quantitative and qualitative composition of the intestinal microflora in normal conditions, retard the growth and reproduction of pathogenic and opportunistic microbes in it
Intestinal peristalsis
Isolation of immunoglobulins
Enzymatic activity
Mucus containing microbial growth inhibitors
Intestinal saprophytes, in comparison with pathogenic bacteria, contain a large number of enzymes, multiply more actively, therefore it is easier to utilize nutrients and oxygen. They produce a variety of bactericidal and bacteriostatic substances, including antibiotic-like ones.
Small intestine All microorganisms that normally colonize the large intestine are divided into three groups:
main (lactobacilli, bifidobacteria and bacteroids),
concomitant (strains of E. coli, enterococci)
final (staphylococcus, fungi, proteus).
In the large intestine of a healthy person, the number of microorganisms is 10 in 11 - 10 in the 12th c.u. per g. Anaerobic bacteria species prevail - 90-95% of the total composition. These are bifidobacteria, bacteroids, lactobacteria, veilonella, peptostreptococci, clostridia.
About 5-10% - facultative anaerobes - and aerobes - Escherichia coli, lactose negative enterobacteriaceae, enterococci, staphylococci, yeast-like fungi.
Significance for the body Research shows that the relationship between gut and flora is not just commensalism (that is, harmless coexistence), but rather a form of mutualism, that is, a mutually beneficial relationship. Although humans can survive without gut flora, microorganisms perform a number of beneficial functions for the host, such as anaerobic digestion of unused material to provide energy, training the immune system, and preventing the growth of harmful species. However, the fauna of the intestines is not always extremely useful, it is believed that some microorganisms in certain cases can cause disease.
Microorganisms
Bacteria that can be found in the human intestine
Bacteria Occurrence (%)
Bacteroides fragilis 100
Bacteroides melaninogenicus 100
Bacteroides oralis 100
Enterococcus faecalis 100
Escherichia coli 100
Enterobacter sp. 40–80
Klebsiella sp. 40–80
Bifidobacterium bifidum 30–70
Staphylococcus aureus 30-50
Lactobacillus 20-60
Clostridium perfringens 25–35
Proteus mirabilis 5–55
Clostridium tetani 1–35
Clostridium septicum 5-25
Pseudomonas aeruginosa 3-11
Salmonella enterica 3–7
Faecalibacterium prausnitzii - Often
Peptostreptococcus sp. ?often
Peptococcus sp. ?often
Dysbacteriosis
Dysbacteriosis (dysbiosis) - these are any quantitative or qualitative changes in the normal human microflora typical for a given biotope, arising as a result of exposure to various adverse factors on a macro- or microorganism.
Microbiological indicators of dysbiosis are:
1) decrease in the number of one or more permanent species;
2) the loss of certain signs by bacteria or the acquisition of new ones;
3) an increase in the number of transient species;
4) the emergence of new species unusual for this biotope;
5) weakening of the antagonistic activity of normal microflora.
The reasons for the development of dysbiosis can be:
1) antibiotic and chemotherapy;
2) severe infections;
3) severe somatic diseases;
4) hormone therapy;
5) radiation effects;
6) toxic factors;
7) vitamin deficiency.
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Intestinal dysbiosis is a clinical and laboratory syndrome associated with a change in the qualitative and / or quantitative composition of the intestinal microflora, followed by the formation of metabolic and immunological disorders, with the possible development of gastrointestinal disorders.
Classification by species or group of organisms
Excess staphylococcus - stuffylococcal dysbiosis
Dysbacteriosis, conditioned by opportunistic enterobacteriaceae, yeast-like fungi, the association of opportunistic microorganisms, etc.
Dysbacteriosis -
In the gastrointestinal – the human intestinal tract is found obligate (the main microflora), facultative (opportunistic and saprophytic microflora) and transient microflora (microorganisms accidentally entered the gastrointestinal tract).
In the esophagus and stomach, a transient microflora is usually determined, which enters them with food or from the oral cavity. Despite the ingress of a large number of microbes into the stomach, a small number of microorganisms (less than 10 3 CFU / ml) is normally detected in the stomach in healthy people. This is due to the acidic pH of the stomach contents and the bactericidal properties of gastric juice, which reliably protects a person from the penetration of pathogenic and opportunistic bacteria into the intestines. Mostly acid-fast bacteria are found in gastric juice – lactobacilli, yeast fungi. Some people have streptococci in it, S. ventriculus, B. subtilis, anaerobic gram-positive cocci.
In the thickness of the gastric mucosa, anaerobes of Veilonella, bacteroids, and peptococci are found.
When studying healthy children aged 8 – For 15 years, staphylococci, streptococci, enterococci, corynebacteria, peptococci, lactobacilli and propionibacteria were detected in the mucous membrane of the antrum of the stomach. Microbiological examination of stomach contents is relatively rare.
The number and composition of microbes in the small intestine varies depending on the section of the intestine. The total number of microbes in the small intestine is no more than 10 4 – 10 5 CFU / ml content. A low concentration of microbes is due to the action of bile, the presence of pancreatic enzymes, intestinal peristalsis, which ensures the rapid removal of microbes into the distal intestine; the production of immunoglobulins by the cells of the mucous membrane, the state of the intestinal epithelium and mucus secreted by the goblet cells of the intestine containing inhibitors of microbial growth. The microflora of the small intestine is presented mainly by gram-positive optional – anaerobic and anaerobic bacteria (enterococci, lactobacilli, bifidobacteria), yeast-like fungi, bacteroids and veilonella are less common, enterobacteria are extremely rare. After eating, the number of microbes in the small intestine can increase significantly, but then in a short time it quickly returns to its original level. In the lower parts of the small intestine (in the ileum), the number of microbes increases and can reach 10 7 CFU / ml of content.
In the large intestine, gram-positive flora changes to gram-negative. The number of obligate anaerobes begins to exceed the number of facultative anaerobes. Representatives of microbes characteristic of the large intestine appear.
The growth and development of microbes in the large intestine is facilitated by the absence of digestive enzymes, the presence of a large amount of nutrients, prolonged presence of food, structural features of the mucous membrane and, in particular, the mucous overlays of the large intestine. They determine the organ tropism of some species of anaerobic bacteria, which, as a result of their vital activity, form products used by the facultative anaerobic flora, which in turn create conditions for the life of obligate anaerobes.
In the human large intestine there are more than 400 species of various microbes, and the number of anaerobes is 100 – 1000 times the number of facultative anaerobes. Obligate anaerobes make up 90-95% of the total composition. They are represented by bifidobacteria, lactobacilli, bacteroids, veilonella, peptostreptococci, clostridia and fusobacteria (Fig. 1)
The share of other microorganisms is 0.1 – 0.01% is a residual microflora: enterobacteria (Proteus, Klebsiella, Serrata), enterococci, staphylococci, streptococci, bacilli, yeast fungi (Fig. 3). Conditionally pathogenic amoebas, Trichomonas, some types of intestinal viruses can live in the intestine.
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In the human large intestine, M-mucous microflora is secreted - microbes that live in the thickness of the mucous membrane. The number of microbes in the thickness of the mucous membrane is 10 8 CFU per gram of intestinal tissue. Some authors call mucous microflora – "Bacterial turf".
Microbes living in the lumen of the human intestine are called P – microflora (luminal or cavity). The number of microbes in human feces reaches 10 12 CFU / g. contents and accounts for 1/3 of human fecal masses. Facultative anaerobes account for 5-10% of the microflora of the large intestine. It includes: Escherichia coli and enterococci (Fig. 2)
Obligate permanent microflora of the human intestine is represented mainly by bifidobacteria, lactobacilli, Escherichia coli and enterococci. Optional flora is less common, it is represented by other anaerobic and optional – anaerobic bacteria.
Dysbacteriosis (dysbiosis, dysmicrobiocenosis) of the intestine – qualitative and quantitative changes in microflora. Dysbacteriosis is accompanied by a decrease in the obligate anaerobic flora (bifidobacteria and lactobacilli) and an increase in conditionally pathogenic microflora, which are normally absent or found in small numbers (staphylococci, pseudomonas, yeast-like fungi, proteas, etc.). The appearance of dysbiosis can lead to immunological disorders with the possible development of gastrointestinal disorders.
Exogenous and endogenous factors contribute to the development of dysbiosis in humans: infectious diseases of the digestive system, diseases of the gastrointestinal tract, liver, oncological pathology, allergic diseases. Changes in microflora are facilitated by the intake of antibiotics, hormones, immunosuppressants, cytostatics, psychotropic, laxative and contraceptive drugs, the effect on the body of industrial poisons and pesticides. The season of the year, human nutrition, stress, smoking, drug addiction, alcoholism have a great influence on the composition of the microflora.
The appearance of dysbiosis in newborns can be caused by bacterial vaginosis and mastitis in the mother, resuscitation, late attachment to the breast, prolonged stay in the maternity hospital, immaturity of intestinal motor function, breast milk intolerance, maladsorption syndrome.
In infancy, the development of dysbiosis is facilitated by: early artificial feeding, frequent acute respiratory viral infections, rickets, anemia, malnutrition, allergic and neuropsychiatric diseases.
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V.M. Bondarenko, D.M.N, professor,
Head of the Laboratory of Genetics of Virulence of Bacteria, NIIEM
them. N.F. Gamalei, Moscow
In recent years, the problem intestinal dysbiosis
still causes serious controversy, showing sometimes the most polar points of view. However, everyone agrees that it is impossible to outline this concept in a strict classification framework. Dysbacteriosis
Is a clinical and laboratory syndrome characterized by quantitative and qualitative disorders in the composition of the obligate
microflora in a particular biotope, developing as a result of a breakdown in adaptation, violation of protective and compensatory mechanisms and leading to immunological and metabolic shifts.
Violation of the intestinal microflora (dysbiosis)seemingly innocent at first glance leads to dire consequences, therefore, doctors of different specialties consider today dysbiosis as the initial link in the formation of multiple organ pathology. With dysbacteriosis, the permeability of the intestinal wall for toxins and allergens increases, intoxication develops, the barrier functions of the liver and skin decrease, which leads to the formation of allergic diseases, impaired parietal digestion and absorption of micronutrients that cause disruptions of protein, fat, cholesterol and bilirubin metabolism in the body, which leads to liver and pancreas diseases... In addition, the synthesis of vitamins, the absorption of calcium and iron salts decreases sharply, which leads to the development of hypovitaminosis, rickets and anemia, and a violation of the protective function of microflora is often accompanied by a breakdown of oral tolerance and a decrease in the body's immunoresistance, being risk factors for frequent ARVI with the formation of complications in the ENT organs and the bronchopulmonary system.
The greatest attention of doctors, scientists and the general public is currently attracted by the intestinal microbiocenosis, that is, the totality of the microbial population of the intestine. The fact is that it is the most numerous microbiocenosis. The gastrointestinal tract is inhabited by an exceptionally diverse anaerobic and aerobic microorganisms, which are distributed both vertically - from the oral cavity to the lower (distal) sections of the colon, - and horizontally - from the lumen to various layers of the mucous membrane (mucous, or parietal microflora). Wherein the largest number of microorganisms is found in the colon human.
In general terms, it should be noted that the mass of normal intestinal microflora of an adult is more than 2.5 kg, in the amount of 10 12 –10 14 CFU (colony-forming units) per 1 gram of feces. Previously, it was believed that the intestinal microflora has 17 families, 45 genera and about 500 species. However, this information should be revised taking into account the latest data obtained in the study of microflora using molecular genetic research methods. Apparently, the total number of previously known and newly identified species will be in the range of one and a half thousand or more.
It is generally accepted that the classification of microorganisms is a system of hierarchical subordinate units, for which the term "taxon" is adopted. At present, all living cellular organisms are usually subdivided into eukaryotes and prokaryotes. The taxon of the highest category is the kingdom of prokaryotes, which unites in the order of hierarchy a system of taxa of different, lower scale or rank: domain, phylum, class, order, family, genus, species. As you know, prokaryotes include two domains: archaea and bacteria.
Recently, P. Eckburg et al. (2005) showed that the parietal and luminal microflora includes 395 phylogenetically separate groups of microorganisms, of which 244 (62%) are completely new. At the same time, 80% (195 out of 244) of new, previously unknown taxonomic groups identified during molecular genetic research refer to microorganisms that do not grow on nutrient media when aspiration samples are grown, both under aerobic and anaerobic conditions. Most of the supposed new phylogenetically distinct groups of microorganisms are representatives of two phyla: Firmicutes and Bacteroitedes. Interesting data were obtained when studying the intestinal microbiota of obese volunteers in comparison with the intestinal microflora of lean ones. In obesity, a 90% decrease in the phyla Bacteroitedes and a 20% increase in the phyla Firmicutes in the intestinal parietal microbiota are shown (Ley R.E. et al., 2005;
Turubaugh P.J. et al., 2006). The scientific classification of the taxa Firmicutes and Bacteroitedes is at odds with the generally accepted one and requires clarification.
Characterizing human microfloraoften use the terms: obligate (resident, indigenous, autochthonous) and optional (transient, allochthonous, random) microflora. By the nature of the relationship with the macroorganism, pathogenic and non-pathogenic microflora, often referred to as commensal microbes, are differentiated. If representatives of an obligate or facultative microflora caused an inflammatory infectious process, they are considered as causative agents of an opportunistic infection. It should be noted that there is no term "opportunistic pathogenic microorganisms" in the foreign literature, but we found it appropriate to use this term, which is widely used in the domestic medical literature.
In the formed microbiocenosis, 90% are obligate representatives of the microbiota, less than 9.5% are optional and up to 0.5% are random microorganisms. About 20% of microbiota representatives live in the oral cavity (more than 200 species), 40% - in the gastro-duodenal and distal parts of the gastrointestinal tract, 18–20% are in the skin, 15–16% - in the oropharynx, and 2–4 % - on the urogenital tract of men. In women, the vaginal biotope accounts for about 10% of the normal flora.
The human microflora is a complex self-regulating system that can recover with proper correction. Based on these positions, liquid synbiotic biocomplexes were created "Normoflorins"containing viable metabolically active probiotic bacteria (latobacilli and bifidobacteria) that can compete with pathogenic microorganisms for space on mucous membranes, thereby suppressing its reproduction and activity.
The high content of microbial metabolites ensures the rapid restoration of metabolic, immunological, enzymatic and synthetic processes in the body.
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Human organism inhabited (colonized) by more than 500 species of microorganisms that make up the normal human microflora in a state of equilibrium (eubiosis)with each other and the human body. Microflora is a stable community of microorganisms, i.e. microbiocenosis.It colonizes the surface of the body and cavities that communicate with the environment. The habitat of the community of microorganisms is called biotope.Normally, microorganisms are absent in the lungs and uterus. Distinguish between the normal microflora of the skin, mucous membranes of the mouth, upper respiratory tract, digestive tract and genitourinary system. Resident and transient microflora are distinguished from normal microflora. Resident (permanent) obligate microflora is represented by microorganisms that are constantly present in the body. Transient (non-permanent) microflora is not capable of long-term existence in the body.
Microflora of the digestive tract is the most representative in terms of its qualitative and quantitative composition. In this case, microorganisms live freely in the cavity of the digestive tract, and also colonize mucous membranes.
In the mouth inhabited by actinomycetes, bacteroids, bifidobacteria, eubacteria, fusobacteria, lactobacilli, hemophilic sticks, leptotrichia, neisseria, spirochetes, streptococci, staphylococci, veilonella, etc. Fungi of the genus Candida and protozoa are also found. Associates of normal microflora and their waste products form dental plaque.
Microflora of the stomach represented by lactobacilli and yeast, single gram-negative bacteria. It is somewhat poorer than, for example, the intestines, since gastric juice has a low pH value, which is unfavorable for the life of many microorganisms. With gastritis, gastric ulcer, curved forms of bacteria - Helicobacter pylori are found, which are the etiological factors of the pathological process.
In the small intestine there are more microorganisms than in the stomach; here bifidobacteria, clostridia, eubacteria, lactobacilli, anaerobic cocci are found.
The largest number of microorganisms accumulates in colon... 1 g of feces contains up to 250 billion microbial cells. About 95% of all types of microorganisms are anaerobes. The main representatives of the colon microflora are: gram-positive anaerobic bacilli (bifidobacteria, lactobacilli, eubacteria); gram-positive spore-forming anaerobic rods (clostridia, perfringens, etc.); enterococci; gram-negative anaerobic rods (bacteroids); gram-negative facultative anaerobic bacilli (Escherichia coli and similar bacteria.
Colon microflora - a kind of extracorporeal organ. It is an antagonist of putrefactive microflora, as it produces lactic acid, acetic acid, antibiotics, etc. It is known for its role in water-salt metabolism, regulation of intestinal gas composition, metabolism of proteins, carbohydrates, fatty acids, cholesterol and nucleic acids, as well as the production of biologically active compounds - antibiotics, vitamins, toxins, etc. The morphokinetic role of microflora is its participation in the development of organs and systems of the body; it also participates in physiological inflammation of the mucous membrane and epithelial change, digestion and detoxification of exogenous substrates and metabolites, which is comparable to liver function. In addition, normal microflora plays an antimutagenic role, destroying carcinogenic substances.