Skin microflora. Normal human microflora. Skin structure and function

Human skin is the largest organ of the human body, one of the functions of which is to organize a physical barrier that prevents the penetration of foreign pathogens, while simultaneously providing an “ecological niche” for a variety of commensal microorganisms.

Throughout a person's life, keratinized skin cells, immune cells, and skin microbiota interact to maintain the physical and immune skin barrier, providing homeostasis for the body's health, as well as protective sanogenetic responses to multiple stresses, such as wounds or infections.

Due to constant contact with the external environment, the skin most often becomes a habitat for transient microorganisms. However, there is a stable and well-studied permanent microflora, the composition of which varies in different anatomical zones depending on the oxygen content in the environment surrounding the bacteria (aerobes - anaerobes) and proximity to the mucous membranes (mouth, nose, perianal region), secretion characteristics, and even a person's clothes.

Particularly abundantly populated by microorganisms are those areas of the skin that are protected from light and drying: armpits, interdigital spaces, inguinal folds, perineum.Scientists have found that the number of bacteria on the surface of the skin with an area of ​​1 cm² in a person’s armpits can reach eighty thousand; the number of bacteria in the same area in dry places in humans is only about two thousand.

At the same time, microorganisms of the skin are affected by bactericidal factors of sebaceous and.

The first microbes enter the mother's birth canal, and then from the air of the maternity hospital, from the hands of staff and from the skin of the mother's mammary gland. During this period, staphylococci and fungi of the genus Candida are found in the microflora of the child’s skin, which are later replaced by normal microflora.

The resident microflora of the skin and mucous membranes includes:

• S. epidermidis;
• Micrococcus spp.;
• Sarcina spp.;
• coryneform bacteria;
• Propionibacterium spp.

As part of the transitory:

• S. aureus;
• Streptococcus spp.;
• Peptococcus spp.;
• Bacillus subtilis;
• Escherichia coli;
• Enterobacter spp.;
• Acinetobacter spp.;
• Lactobacillus spp.;
• Candida albicans and many others.

In areas where there are accumulations of sebaceous glands (genitals, outer ear), acid-fast non-pathogenic mycobacteria are found. The most stable and at the same time very convenient for study is the microflora of the forehead area.

The vast majority of microorganisms, including pathogenic ones, do not penetrate intact skin and die under the influence of the bactericidal properties of the skin.

Factors that can have a significant impact on the removal of non-permanent microorganisms from the surface of the skin include: the acidity of the environment, the presence of fatty acids in secretions and the presence of lysozyme.

Neither excessive sweating, nor washing or bathing can remove the normal permanent microflora or significantly affect its composition, because the microflora is quickly restored due to the release of microorganisms from the sebaceous and sweat glands, even in cases where contact with other areas of the skin or with the external environment is completely stopped.

Therefore, an increase in the contamination of a particular area of ​​the skin as a result of a decrease in the bactericidal properties of the skin can serve as an indicator of a decrease in the immunological reactivity of the macroorganism.

The causative agents of purulent-inflammatory processes can be representatives of various genera, the vast majority of which are classified as so-called “opportunistic” microflora (aerobic, microaerophilic, facultative anaerobic and anaerobic).

Among them, the most common types of genera are: Staphylococcus, Streptococcus, Pseudomonas, Escherichia, Proteus, Citrobacter, Klebsiella, Enterobacter, Hafnia, Serratia, Aeromonas, Alcaligenes, Acinetobacter, Haemophilus, Peptococcus, Bacillus, Clostridium, Corynebacterium, Propionibacterium, Bacteroides, Nocardia, Listeria , Fusobacterium, Neisseria, Mycrococcus, Mycoplasma. Less commonly - Yersinia, Ervinia, Salmonella, Acinetobacter, Moraxella, Brucella, Candida, Actinomyces.

Microorganisms can cause and maintain a purulent process, both in monoculture and in association.

Isaeva Regina

Microflora of human skin and the effect of different types of soap on it

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Research work on the topic:

"Skin microflora and influence

different types of soap on it"

Prepared

Class 4A student

schools - gymnasium No. 139

Isaeva Regina

Scientific adviser:

Shaikhutdinova V.I.

Scientific consultant:

Ph.D. Isaeva G.Sh.

Kazan – 2009

1. Introduction

1.1. Skin structure and microflora

1.2. Constant skin microflora and its role

1.3. Transient microflora

1. Purpose and progress of the study
2. Results.
3. conclusions
4. Conclusion. Rules for hand treatment.

Introduction. The surrounding world is populated by a huge number of microorganisms. It is impossible to even imagine the endless diversity that the world of microbes conceals: they can be found almost anywhere on the planet - in the soil, air, hot springs and waters of the Dead Sea, and even in the Arctic ice. However, the human body is like a habitable planet inhabited by hundreds of species of microorganisms. Research in recent years gives every reason to say that human skin has a complex and multifaceted microbial flora.

Skin structure and microflora.Human skin consists of three layers - epidermis , dermis and hypodermis, or subcutaneous tissue. The protective function of the skin is mainly carried out by epidermis - the upper, constantly renewed layer. Surface layer of the epidermis - horny layer, consists of dead, constantly exfoliating cells. This layer is designed to protect the body from the penetration of pathogenic microbes.

The skin is inhabited by various microbes. According to modern research, microorganisms that live in the skin and other body tissues outnumber the cells of the human body tens of times. They form communities that are able to regulate our development, resistance to infections and absorption of nutrients. According to microbial diversity researcher Julia Segra from the National Institute for Genomic Research (USA):“Human beings are an amalgam of human and bacterial genomes”. Bacteria and fungi that can reproduce on human skin are conventionally divided into two groups: permanent flora, consisting mainly of cocci (spherical bacteria) and propionic bacteria (anaerobic rods that reproduce only in the absence of oxygen), which do not have a pathogenic effect on the host body , and transient flora, which can cause various diseases.

Permanent microflora and its role.Normal flora is constantly present on the surface of the skin and, as a result of competitive interactions between reproducing microorganisms, prevents the development of transient flora on it. Permanent microflora lives in the stratum corneum (superficial microflora) and in the ducts of the sebaceous and sweat glands, in the hair follicles (deep microflora). It is represented by staphylococci (spherical bacteria in the form of a bunch of grapes), streptococci (spherical bacteria in the form of chains), micrococci (single spherical bacteria), corynebacteria (rods), fungi of the genus Candida and other species. On the skin You can find hundreds of species of bacteria, the total number of which reaches trillions. The colonization of the skin by microorganisms begins from the moment a child is born and continues throughout life. The role of normal microflora is to suppress the growth of pathogenic bacteria, as well as participate in the processing of skin proteins, free fatty acids and sebum. One's own microflora can also become pathogenic, that is, under certain conditions, for example, with decreased immunity, with microtrauma, these microorganisms can cause purulent skin lesions. For example, propionic bacteria together with staphylococci can cause the formation of acne. There is much evidence in favor of the influence of microflora on the development of a number of non-infectious skin diseases, such as atopic dermatitis, rosacea, psoriasis and acne.

Transitory microflora.Transient microflora gets on the skin through contact with various objects, the ground, during handshakes, communication with animals, etc. It is represented by sarcins, bacilli, mycobacteria, molds, etc. But under the influence of the bactericidal properties of the skin and constant microflora, these microbes do not stay for long and are removed from the surface of the skin. Transient microorganisms can cause various diseases, for example, E. coli - an intestinal infection. When the skin is damaged, pathogenic microorganisms can penetrate deep into the skin and cause diseases such as dermatomycosis (scab, trichophytosis, microsporia), tetanus, gas gangrene, etc.

The composition of microflora and its quantity depends on various factors: temperature, humidity, age. Also important factors are gender, the state of a person’s immunity, and even the activity with which he uses various cosmetics and performs hygiene procedures. When washing the skin, the upper stratum corneum peels off. And along with it, microbes, including pathogenic ones, are also removed. The amount of normal microflora is quickly restored due to intake from the deep layers of the skin.

Purpose Our research was to study the effect of different types of soap on normal microflora.

Progress of the study.The study was conducted on volunteers from among medical university students. First, the skin of the hands was washed using a swab soaked in a sterile saline solution, then after washing the hands with soap, the skin was washed again. We sowed both flushes onto a nutrient medium and grew the crops in a thermostat at a human body temperature of 37° C. The next day we counted the number of grown colonies. (A colony is formed when one bacterial cell divides.)

results are presented in the table.

Table. Number of microorganisms before and after hand washing

* CFU - colony forming unit

When using baby soap and Nivea soap, the number of bacteria decreased slightly - approximately 1.5 times. When using soap with antibacterial additives, the number of microbes decreased by 20-60 times. In the control, when washing hands without soap only with tap water, the number of microbes did not change.

Conclusions.

Thus, we can conclude that for regular use we can recommend the use of baby soap, because... it does not significantly affect the normal microflora of the skin. When using antibacterial soap, the number of microbes is reduced tens of times, but with its constant use, the protective role of normal microflora is reduced, which can lead to increased reproduction of pathogenic species. Therefore, antibacterial soap should be used only when necessary, for example, when pustules or acne appear on the skin. And washing your hands only with tap water does not cleanse your skin of germs.

Conclusion. In recent years, ideas about skin microflora have begun to change. Typically, bacteria living on the skin were considered only as a potential source of infection. This shaped ideas about skin hygiene; one of the basic rules was the desire to disinfect it in every possible way. However, today ideas have changed. We should not achieve complete destruction of the microflora on the skin, as this opens the way for pathogenic pathogens. To prevent diseases transmitted through dirty hands, you must follow the following hand washing rules.

1. Hand hygiene is carried out:

• before eating or working with food;
• after visiting the toilet;
• for any contamination of hands.

To wash your hands in public places you must:

1. Liquid dosed neutral soap or individual disposable soap in pieces. Opened liquid or bar reusable non-individual soap quickly becomes infected with germs.
2. Napkins measuring 15x15 cm are disposable, clean for blotting hands. Using a towel (even an individual one) is not advisable, because it does not have time to dry and, moreover, is easily contaminated with germs.

1. Hand treatment rules:

All jewelry and watches are removed from hands, as they make it difficult to remove microorganisms. Hands are soaped and then rinsedwarm running water and everything repeats itself from the beginning. It is believed that the first time you soap and rinse with warm water, germs are washed off from the skin of your hands. Under the influence of warm water and self-massage, the pores of the skin open, so when repeated soaping and rinsing, germs are washed away from the opened pores.

Warm water makes the soap work more effectively, while hot water removes the protective oil layer from the surface of your hands. Therefore, you should avoid washing your hands with too hot water.

List of used literature.

1.Noble W.K. Microbiology of human skin. - M.: Medicine, 1986. - 496 p.

2. Ivanov A.A. Microecology of human skin and its relationship with the immune status of the body. // Materials of the scientific and practical conference “Microflora of human skin - clinical and diagnostic significance”. - M. - 1989. - P.3-11

3. Klemparskaya N.N. Changes in skin microflora under the influence of exogenous and endogenous factors. //Materials of the scientific and practical conference “Microflora of human skin - clinical and diagnostic significance”. - M. - 1989. - P.12-23.

4. Petrovskaya V.G., Marko O.P. Human microflora in normal and pathological conditions. - M., -1976. - P. 104- 111

5. Polyansky O.S. Home for bacteria, or what we know about skin microflora. - “Cosmetics and Medicine” - 2008. - No. 6.

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Due to constant contact with the external environment, the skin most often becomes a habitat for transient microorganisms. However, there is a stable and well-studied permanent microflora, the composition of which varies in different anatomical zones depending on the oxygen content in the environment surrounding the bacteria (aerobes – anaerobes) and proximity to mucous membranes (mouth, nose, perianal area), secretion characteristics, and even human clothing.

Particularly abundantly populated by microorganisms are those areas of the skin that are protected from light and drying: armpits, interdigital spaces, inguinal folds, perineum. At the same time, bactericidal factors of the sebaceous and sweat glands influence microorganisms of the skin.

The first microbes enter human skin during the passage of the mother’s birth canal, and then from the air of the maternity hospital, from the hands of staff and from the skin of the mother’s mammary gland. During this period, staphylococci and fungi of the genus Candida, which are later replaced by normal microflora.

The resident microflora of the skin and mucous membranes includes: S. epidermidis; Micrococcus spp.; Sarcina spp.; coryneform bacteria ; Propionibacterium spp.

As part of the transitory: S. аureus, Streptococcus spp., Peptococcus spp., Bacillus subtilis, Escherichia coli, Enterobacter spp., Acinetobacter spp., Lactobacillus spp., Candida albicans and many others.

In areas where there are accumulations of sebaceous glands (genitals, outer ear), acid-fast non-pathogenic mycobacteria are found. The most stable and at the same time very convenient for study is the microflora of the forehead area.

The vast majority of microorganisms, including pathogenic ones, do not penetrate intact skin and die under the influence of the bactericidal properties of the skin.

Factors that can have a significant impact on the removal of non-persistent microorganisms from the skin surface include: acidic reaction of the environment, the presence of fatty acids in the secretions of the sebaceous glands and the presence of lysozyme.

Neither excessive sweating, nor washing or bathing can remove the normal permanent microflora or significantly affect its composition, because the microflora is quickly restored due to the release of microorganisms from the sebaceous and sweat glands, even in cases where contact with other areas of the skin or with the external environment is completely stopped. Therefore, an increase in the contamination of a particular area of ​​the skin as a result of a decrease in the bactericidal properties of the skin can serve as an indicator of a decrease in the immunological reactivity of the macroorganism.

The causative agents of purulent-inflammatory processes can be representatives of various genera, the vast majority of which are classified as so-called “opportunistic” microflora (aerobic, microaerophilic, facultative anaerobic and anaerobic). Among them, the most common types of childbirth are: Staphylococcus, Streptococcus, Pseudomonas, Escherichia, Proteus, Citrobacter, Klebsiella, Enterobacter, Hafnia, Serratia, Aeromonas, Alcaligenes, Acinetobacter, Haemophilus, Peptococcus, Bacillus, Clostridium, Corynebacterium, Propionibacterium, Bacteroides, Nocardia, Listeria, Fusobacterium, Neisseria, ccus, Mycoplasma. Less often - Yersinia, Ervinia, Salmonella, Acinetobacter, Moraxella, Brucella, Candida, Actinomyces.

Microorganisms can cause and maintain a purulent process, both in monoculture and in association.

The human microflora is a collection of many microbiocenoses, includes hundreds of different species and is almost an order of magnitude larger in number than the number of cells of all organs and tissues of the human body.

All open cavities and human skin are populated by microbial populations that are most adapted to the specific conditions of each specific biotope. Microbiocenoses arose in places of contact of the human body with the environment - skin, gastrointestinal mucosa, vagina. They are in a state of dynamic equilibrium with changing environmental conditions.

The physiological status of the body and the state of its nonspecific defenses are associated with the vital activity of microflora. Representatives of normal microflora protect the skin and mucous membranes from penetration and rapid reproduction of pathogenic and opportunistic microorganisms, and perform a number of other functions.

Microbiocenoses of the human body are unique endogenous microbial genetic funds. They store a huge amount of genetic information, both plasmid and chromosomal. Obligate microflora adhered to the epithelium is capable of exchanging genetic information with the cells of the macroorganism. The human genome contains nucleotide sequences characteristic of more than 200 species of bacteria and 500 species of retroviruses. Through endocytosis, the microflora can receive cellular material from the host and transfer its antigens to the cells of the macroorganism. Thus, the microflora acquires receptors or host antigens and, accordingly, protection from the immune system. This may also explain the widespread distribution of cross-reacting antigens of certain microbial cells and tissues of the host body. This group of antigens is one of the factors inducing the development of autoimmune conditions.

The composition and functions of human microbial biocenoses depend on:

· age,

· nutritional characteristics,

· climate,

· environmental conditions, etc.

A healthy lifestyle and lack of stress support non-pathogenic biocenoses. Age-related changes can contribute to a decrease or increase in the pathogenicity of a number of pathogens.

The influence of environmental factors modifies not only the protective forces of the macroorganism, but also changes the properties of the microorganism.

Microbial biocenoses are quite sensitive biological systems that respond to many factors. For example, with inadequate or reduced nutrition, the dynamics of changes in microbiocenoses in various biotopes of the human body is of the same type - there is a decrease in the number of resident forms of bacteria with an increase in the number of opportunistic and pathogenic species.

Changes in the species composition of microbiocenoses of the body of a healthy person and its immunobiological factors reflect the stage of tension of adaptation mechanisms.

To assess the homeostasis of the body and monitor the nutritional status of people, we can recommend the study of microbiocenoses of the skin and pharynx, as they are the most accessible and quickly respond to external influences.

Individual microbial biocenoses actively interact with each other and with the host organism. The total number of microbial cells colonizing the human body is 1–3 orders of magnitude greater than all the cells that make up all human organs. The most densely populated ecosystem is colonic biotope(about 60% of human microflora is concentrated in it). 15–20% of microbial populations inhabit skin. 15–16% of microorganisms are in oropharynx, V vaginal biotope Women contain 9–10% microflora.

Given the multicomponent nature of the human microflora, the basis of normal microbiocenoses of all open cavities and skin is made up of only a few groups of indigenous bacteria, among which saccharolytic, asporogenic, non-pathogenic anaerobes always dominate. These include bifidobacteria, lactobacilli and propionic acid bacteria, which represent the basic component main (obligate, indigenous, resident) human microflora.

Thus, lactobacilli are found in all biotopes of the digestive tract, starting from the oral cavity and ending with the rectum, and are the dominant flora of the vaginal biotope.

Different biotopes are characterized by certain species specificity: epidermal staphylococci predominate in the deep microflora of the skin, non-pathogenic streptococci predominate in the microflora of the nasopharynx, and bifidobacteria and lactobacilli occupy a dominant position in the intestinal microbiocenosis.

Bacteria of the genus Staphylococcus are in most cases sown from all biotopes of the human body. Normally, they are represented by saprophytic staphylococci, mainly from the species S. epidermidis.. Pathogenic staphylococci (S. aureus) are found in small quantities and, with normal functioning of the microecological system, do not cause pathological processes in the body. The development of endogenous staphylococcal infections is possible only with a decrease in the colonization resistance of the body.

In a healthy human body, the microbiocenosis, consisting of a high population level of indigenous protective flora and a small number of opportunistic microorganisms, is an open self-regulating ecosystem. This ecosystem is capable of independently maintaining an optimal ratio between individual groups of microbiota. The constant presence of opportunistic microorganisms in the biocenosis makes a certain contribution to the positive effect of eubiosis on the host organism. Their permissible concentration is strictly controlled by the protective properties of the indigenous normal flora and the host’s immune system. Opportunistic microorganisms participate in the biosynthetic, metabolic and digestive functions of the microbiocenosis, and constant antigenic irritation of the intestinal wall stimulates the local immune mechanisms of the macroorganism.

If the optimal relationship between the components of the biocenosis is violated, some of its normal representatives can cause endogenous infections. Dysbiosis leads to sensitization of the body with many clinical manifestations of allergies, can cause intoxication, exhibit mutagenic properties and have many other negative effects on the body.

All local microecosystems closely interact with each other and with the host organism, forming a single symbiotic system due to the presence of complex and diverse regulatory mechanisms. In this case, a single microecological system (microbiota) is formed, which is an important multifunctional integral part of the human body.

Thanks to the “cooperation” between the organisms inhabiting the macroorganism, the human microecological system acts as a single whole, working in concert for the system in which it is localized. The mechanisms for maintaining the stability of qualitative and quantitative parameters of human microflora have not been fully studied.

The symbiotic relationship between the host organism and its autoflora suggests the presence of a complex and multifaceted mechanism. This mechanism is implemented at the metabolic, regulatory, intracellular and molecular genetic levels. These relationships are vital for both humans and the microbial populations inhabiting their bodies.

Therefore, isolating one pathogen as the leading etiological factor is not always possible. In the vast majority of cases, we should be talking about a pathogenic biocenosis or microbial biofilm.

The microbiocenosis of various human organs and cavities is a very sensitive indicator system. This system is capable of responding with qualitative and quantitative changes to any physiological and pathological changes in the state of the macroorganism and preventing the invasion of pathogenic microorganisms.

Assessment of the qualitative and quantitative composition of resident microflora and identification of indicator microorganisms make it possible to assess the stage of adaptation, as well as make a pre-nosological diagnosis of the status of the body, reflecting the functional state of the barrier-protective functions of the skin, the local humoral system of the gastrointestinal tract (saliva) and excretory subsystems (urine). With the development of adaptation, the number of indicator microorganisms and their associations changes (sowing representatives of 2-3 genera of 1 family at the same time). A system for assessing an organism based on microecological indicators can be used as an indicator of the adverse effects of chemical pollution of the environment.

In various biological environments there is " critical microbial number»

· Borderline states of the body: in saliva - up to 50 colonies, microbial associations - up to 10 colonies; on the skin - up to 30 and up to 5, respectively; in urine - up to 50 and up to 10, respectively),

· Failure of adaptation: saliva - over 50 and 10, respectively, etc.,

Pathological disorders in the body: in saliva above 100 and 60, respectively, on the skin - over 80 and 40, in urine - over 200 and 70.

In the last decades of the 20th century there was a radical change in the microenvironment in the human community. Under the influence of environmental pollution and antibacterial agents, the stable human bacterial microbiocenosis was destroyed. Biologically viable symbioses with bacteria have been lost. The endoecological balance is disrupted in favor of the viral microenvironment.

As a result, slow viral infections, including AIDS, can be considered as a symptom of deep genetic disorders of the internal environment of the human body caused by a change in microbiocenosis.

The biological state of the human body has changed. There has been a transition from bacterial carriage and symbiosis with the bacterial internal environment, functioning on the principles of mutualism - the highest form of mutually beneficial symbiont relationships, to a new state. This condition creates favorable conditions for long-term persistence of viruses in the human body.

Dysbacteriosis- changes in the composition and quantitative ratios of microflora that normally populate hollow organs communicating with the environment (upper respiratory tract, intestines) and human skin.

Formation of human microflora.

As is known, the gastrointestinal tract of a newborn is sterile. Within a few hours after birth, it begins to be colonized by strains of bifidobacteria. streptococci, E. coli, etc. After a day, anaerobic lactobacilli and enterococci can already be detected in the intestines, and from about the 10th day, bacteroids multiply intensively. After about a month, a stable and at the same time individual microbiocenosis is established.

The colonization of the human body by microflora begins during the passage of the fetus through the mother’s genital tract during childbirth. Therefore, the main source of the initial microorganisms on the basis of which the biocenoses of each individual are formed are representatives of the mother’s vaginal biocenosis.

The main microorganism that determines intestinal biocinosis is bacteria bifidum. To colonize bifidobacteria, β-lactase from human milk is required (cow's milk contains α-lactase).

The formation of the microflora of a newborn baby is determined:

1. The state of the microflora of the mother’s intestines and vagina;

2. The state of the microflora of the maternity room;

3. The state of the microflora of the skin and breast nipples;

4. Type of feeding (artificial feeding contributes to the development of dysbiosis);

5. Taking medications and, above all, antibiotics;

6. Injected preparations of pure cultures of microorganisms.

Formation of qualitative and quantitative composition of microflora:

· regulated by the mechanism of intermicrobial interactions within each microecosystem,

· controlled by physiological factors of the host’s body in the dynamics of its life.

The activity of microorganisms depends on the factors of the internal environment of the body:

· biochemical (level of cholesterol, peroxides, superoxide radicals, hormones, etc.)

· biophysical (pH, temperature, osmotic pressure, etc.) indicators.

There is a complex spatiotemporal picture of changes in microbiocenoses in the human body. Pathogenic microorganisms can appear, disappear and reappear in different parts of the body. This is due to both the microbes’ own activity and changes in local immunity, capillary blood flow, lymphodynamics, local releases of hormones, etc.

In orthodox medicine there are no methods and means of monitoring and predicting such a spatio-temporal picture. For example, in a patient, laboratory diagnostics of materials from the urogenital tract do not reveal the actor Ureaoplasma urealyticum. At the same time, they cause an active inflammatory process in the joints and, upon more detailed examination, are detected in the synovial fluid.

Microbiocenosis of the skin.

The skin is considered the largest organ of the human body. It represents a unique system closely related to the internal environment of the body and its external environment.

The skin is abundantly populated with microorganisms. Microbial contamination, depending on the area of ​​the skin, varies from several units to hundreds of thousands of cells per square centimeter. The indigenous flora is concentrated in the deeper layers, in the area of ​​the mouths of the pilosebaceous follicles. The surface microflora of the skin is usually random.

Skin microbiocenosis has been little studied. There is evidence that the most common representatives of skin microflora are staphylococci (S. epidermidis and S. saprofiticus) and fungi of the genus Candida.

Normal skin microflora plays an important role in maintaining body homeostasis. The microflora of the skin is closely connected with the state of the macroorganism, with its immune status. Adverse effects on the body, causing immune suppression, are accompanied by characteristic changes in the microecology of the skin with the development of dysbacteriosis.

Characteristics of skin microbiocenosis is a very sensitive indicator of the immunoreactive state of the human body. Under the influence of unfavorable factors, a structural restructuring of the skin microbiocenosis occurs, accompanied by a change in absolute dominants and an increase in species diversity. These changes are directly dependent on the duration of the adverse effect.

When exposed to harmful environmental factors, the number of normal symbionts decreases and opportunistic microorganisms grow. With a decrease in the resistance of the human body, opportunistic microorganisms are able to exhibit their pathogenicity.

The surface of human skin, especially its exposed parts, is contaminated with various microorganisms; here, from 25,000,000 to 1,000,000,000 microbial individuals are determined.

The native microflora of human skin is represented by sarcins, staphylococci, diphtheroids, some types of streptococci, bacilli, fungi, etc.

In addition to the microflora characteristic of the skin, transient microorganisms may be present here, which quickly disappear under the influence of the bactericidal properties of the skin. Cleanly washed skin has a great ability to self-cleanse. The bactericidal nature of the skin reflects the general resistance of the body.

Intact skin is impenetrable to most microorganisms, including pathogenic ones. If their integrity is violated and the body's resistance decreases, skin diseases can occur.

Sanitary and bacteriological examination of the skin

Sanitary and bacteriological examination of the skin is carried out using two methods:

Sowing fingerprints on MPA in Petri dishes, followed by macroscopic and microscopic examination of the grown colonies.

Culture of skin swabs to determine the total microbial count and E. coli.

Using a swab soaked in 10 ml of sterile saline, carefully wipe the palms, subungual, and interdigital spaces of both hands. The tampon is rinsed in a test tube with saline solution and the initial wash is examined for the total microbial count and the presence of E. coli.

Determination of total microbial count

1 ml of the wash is placed in a sterile Petri dish, 12-15 ml of melted and cooled to 45 0 MPa is poured, the contents of the dish are mixed and after the agar has solidified, the crops are incubated at 37 0 C for 24-48 hours. The grown colonies on the surface and in the depth of the agar can be counted done using a magnifying glass.

Definition of Escherichia coli

The remaining amount of the wash is placed in a test tube with glucose-peptone medium. The crops are incubated at 43 0 C for 24 hours. If gas formation occurs, they are sown on Endo medium. The growth of red colonies on this medium will indicate the presence of E. coli in the washout, indicating fecal contamination of the hands.

Microflora of the oral cavity

The oral cavity has favorable conditions for the development of microorganisms: the presence of nutrients, optimal temperature, humidity, and the alkaline reaction of saliva.

In maintaining the qualitative and quantitative constancy of the normal microflora of the oral cavity, the main role is played by saliva, which has antibacterial activity due to the enzymes it contains (lysozyme, lactoferrin, peroxidase, nuclease) and secretory immunoglobulins.

By the end of the first week, streptococci, Neisseria, lactobacilli, yeast-like fungi, and actinomycetes are found in the oral cavity of newborns. The quantitative and species composition of oral microbes depends on the diet and age of the child. During teething, obligate gram-negative anaerobes appear.

More than 100 species of microorganisms are found in the oral cavity, most of which are aerobes and facultative anaerobes.

The bulk of oral microorganisms are localized in dental plaque: 1 mg of dry mass of dental plaque contains about 250 million microbial cells. A large number of microorganisms are found at the neck of the tooth, in the space between the teeth and in other parts of the oral cavity that are inaccessible to washing with saliva, as well as on the mucous membranes of the pharyngeal tonsils. Individual fluctuations in the qualitative and quantitative composition of the oral microflora depend on age, diet, hygiene skills, resistance of the mucous membrane, and the presence of pathological processes in the teeth and gums.

The resident group of oral bacteria consists of streptococci (Streptococcussalivarius), non-pathogenic staphylococci, saprophytic neisseria, corynobacteria, lactobacilli, bacteroides, fusiform bacteria, yeast-like fungi, actinomycetes, mycoplasmas (M.orule), protozoa (Entamoebabuccalis).

Among the facultative microorganisms there are enterobacteria (genus Esherichia, Klebsiella, Enterobacter, Proteus), Pseudomonas aeruginosa, spore-forming bacteria (genus Bacillus, Clostridium), microorganisms of the genus Campylobacter (C.consicus, C.sputorum).

For qualitative and quantitative study of the microflora of the oral cavity, bacterioscopic and bacteriological research methods are used.

Bacterioscopic method. The material being studied is dental plaque. The smear is stained with Gram or Burri and the morphological and tinctorial properties of microorganisms are studied.

Bacteriological method. The material for the study is mucus from the throat, which is collected using a sterile cotton swab. Inoculate with the same swab in streaks onto a Petri dish with blood agar. After daily incubation at 37 0 C, smears are prepared from the grown colonies, stained with Gram, and the morphological and tinctorial properties of the isolated culture of microorganisms are studied.