The word “bacteria” first of all brings to mind terrible microbes that are responsible for almost everything - from the banal flu to cancer as a consequence of the disease. So what is the true significance of bacteria in nature and human life? Let's start with the fact that it was bacteria, according to the opinion of scientists that has not yet been refuted, were the first organisms that appeared on our planet. And if these "discoverers" did not release oxygen, then poor humanity would have no chance of survival. Even more, if the bacteria had not attended to the creation of protein as such, then the presence of protein life (including us) could be safely forgotten!

Bacterial cells were the first inhabitants of the Earth and it was they who created all of nature.

If you believe official version history, bacteria appeared on Earth several billion years ago, and then for about a billion years no one prevented them from enjoying life in splendid isolation. In comparison with the history of mankind, numbering some hundreds of thousands of years, this is a huge period. During this time, microorganisms have learned to adapt to environment, changing their structure, and changing the environment, adapting it to their needs.

The vitality of bacteria is incomparable, perhaps, with any living organism on Earth. They live:

• in the ocean depths under monstrous pressure;
• in conditions of arctic cold, and retain the ability to exist after defrosting;
• in hot springs at temperatures of a hundred degrees (and even more!);
• in the human stomach, resisting the action of hydrochloric acid;
• in the vents of underwater volcanoes, where three (minimum) aggressive factors converge simultaneously - temperature, pressure, poisonous gases;
• in the upper rarefied layers of the atmosphere, where it is already closer to cosmic cold than to warm earth;
• deep underground, they survive by eating sulfur compounds and washing down their dinner with oil, etc.

In a word, there is no such corner on our planet and in our body where bacteria would not be found. There is a theory that life appeared on Earth along with bacteria that arrived to us inside some fateful meteorite. This means that microorganisms have managed to survive in absolute vacuum and space cold! And they not only survived, but retained the ability to reproduce, inhabited the entire planet, prepared the ground for the appearance of fungi and algae, which led to an increase in the diversity of life in nature and, as a result, to the emergence of mankind! And this is only the beginning of the answer to the question of what is the importance of bacteria in nature and in human life. In short, without them, there would be no us.

So who are they, bacteria?

In the second half of the 19th century, a new direction in science was formed - microbiology. This science appeared as a branch of medicine and studied the role of bacteria as pathogens. The founders of microbiology were Pascal, Mechnikov, Koch, Erlich and other doctors who were able to consider the connection between tiny creatures and human diseases. The current microbiology is not only concerned with medical problems, it plays a large role in industry (biotechnology) and in a relatively new branch of science - genetic engineering.

Microorganisms (or microbes) are considered to be all living organisms that cannot be seen with the naked eye (without a microscope). In nature, there are three domains (regions):

• viruses;
• protozoa and fungi;
• true bacteria.

Bacteria differ from other domains in their structure - they do not have a nucleus bounded by a membrane. Instead, they have a DNA molecule closed in a loop, which takes on the role of transferring genetic information from the mother cell to the daughter cell.

Bacteria are unicellular organisms with the simplest structure:

• the outer layer is the cell wall;
• thin inner layer - cytoplasmic membrane;
• internal gel-like substance - cytoplasm;
• the prototype of the nucleus (DNA molecule) is the nucleoid;
• "reserve" storage of information (RNA molecules) - ribosomes.

These are just the basic structures of a bacterial cell. Additional ones that appear depending on the functions of the cell or the conditions of its existence include capsules, pili, spores, plasmids, volutin grains and other adaptations developed over billions of years of evolution for the survival of bacteria as a species.

What will we eat...

The further the study of bacteria progressed, the more interesting the picture became. It turned out that the soil that feeds us all was also formed thanks to microorganisms. Not the last role, however, was played by water and air. But it was bacteria that started it.

Further more. Organic substances used by plants are also created by microorganisms (bacteria - producers). Moreover, they use inorganic compounds for this, and take energy from the reactions of photo- and chemosynthesis, that is, from sunlight and chemical transformations. But it is not enough to create organics, something else needs to be done with the dead remains. Otherwise, the planet would have turned into a waste food graveyard a long time ago (to put it mildly). Nature has appointed the same ubiquitous bacteria to the role of scavengers.

Part of the bacteria (decomposers or saprophytes) uses waste organic residues and dead cells as food, decomposing them into simple and inorganic substances, which are then used again.

Thus the circle closes and nothing is wasted. The totality of transformations of chemical elements that make up all living beings is called the circulation of substances. This is a fundamental rule of nature, and it would not be possible without the help of such a tiny and, at first glance, defenseless cell.

... and how to breathe

The first reserves of oxygen on our planet also appeared thanks to bacteria. It sounds strange enough, but oxygen is just a byproduct of the food of photosynthetic microorganisms (phototrophs), so to speak, waste products.

Animals and humans also play a role in maintaining the balance of the atmosphere. The process of photosynthesis requires carbon dioxide, and this is exactly what is released during respiration and during combustion (think of our factories, factories and cars). The circle closes again and there are obvious advantages of the existence of a balanced system.

Another essential element is nitrogen. It is a mandatory part of proteins and nucleic acids, that is, it forms the basis of protein life. Animals and humans get this element from protein-rich foods. It can be of vegetable or animal origin. Animals take protein from plants, but how is it formed in the plants themselves?

There is a small problem here. There is a lot of nitrogen in the atmosphere of our planet (78% of the total volume), but plants cannot absorb it from the air on their own. The soil also contains nitrogen, but very little, and often in compounds that are not suitable for plants to eat. Our little friends come to the rescue, as usual. There is a special breed of bacteria (nitrogen-fixing) that convert nitrogen compounds into nitrates available to plants.

The role of nitrogen-fixing bacteria in nature is to help plants

So, the soil is ready, the atmosphere is created, there is a basis for protein life. After the preparatory work carried out by bacteria, fungi, algae and protozoa appear, increasing the diversity of life and bringing us closer to the Earth.

The basis of life

In the structure of a bacterial cell there are ribosomes (ribonucleoprotein particles). They are responsible for protein synthesis. There can be up to 90 thousand such small pieces in a cell! This shows how important ribosomes are to nature. What is their importance?

The role of ribosomes is the synthesis of protein from amino acids. The sequence of the process is written in the genetic information of RNA (not DNA!). And the catch is this - DNA cannot reproduce itself, it needs a catalyst (trigger), which is a protein. And protein, in turn, cannot be formed without DNA. There is a chicken-and-egg paradox.

It turned out that RNA (ribonucleic acid), which forms the basis of ribosomes, can easily cope with all this. It transmits information, works as a catalyst and transports amino acids, giving out the very valuable protein, the basis of our life.

Ribosome of a bacterial cell

These findings formed the basis of the theory of life "before DNA". Who knows, maybe after some time scientists will have to reconsider the theory of the origin of life on Earth?

Human + bacteria = symbiotic system

Man cannot survive without his bacteria, just as bacteria cannot survive without man. This symbiotic system was formed over a huge amount of time, and an improved and thoroughly tested version has survived to this day.

The total weight of bacteria in the human body is about four kilograms. Approximately two of them are in the gastrointestinal tract. Bacteria cover our body with a kind of invisible cloak, making up the normal human microflora. Everyone has her own, her the main role- protect a person from extraneous "stray" bacteria (if the immune system is in order), killing them or depriving them of food.

By the way, bacteria that live in the gastrointestinal tract play a huge role in the formation and maintenance of the immune system. If you treat them with due respect and do not poison them with harmful food and toxins, then the result will not be slow to affect.

The role of beneficial bacteria in human immunity

Digestion in the human body is impossible without bacteria living in the intestines (not to be confused with the stomach). These microorganisms produce vitamins and enzymes, without which our body will not be able to absorb even the freshest and most healthy food. Oddly enough, but one of these bacteria is E. coli, the one that is responsible for many dangerous diseases. It's all about proportions. As long as the amount of E. coli is normal, a person feels great, but it is worth creating suitable conditions for her, as she will seize power and loudly declare herself.

Not only E. coli, but also many other bacteria, called opportunistic pathogens, exist in the human body without causing harm until a certain time. The trigger mechanism can be a decrease in immunity (injury, illness), an unhealthy lifestyle, bad habits, and stress.

Not everything is so rosy

Now a little about the cons. Bacteria are not always pink and fluffy. It is to them that we owe many diseases, and until we have learned to detect them and at least somehow fight them, then the most terrible epidemics, such as smallpox, plague or cholera.

In the stomach of more than half of humanity, the recently discovered bacterium Helicobacter pylori lives. Scientists who proved the guilt of this "criminal" in intestinal diseases (ulcers, gastritis) were even awarded the Nobel Prize, this study was so important.

And just the other day, information appeared that in the stomach (or rather, its remains) of the famous Tyrolean ice man Ötzi (a mummy found in the Alps in 1991), who lived 5300 years ago, traces of Helicobacter DNA were found. Today, several strains of this bacterium are distinguished, each tied to its own region: African, Asian and a hybrid of these two - European. It turned out that the strain of bacteria in Ötzi's body is of Asian origin, although it should have been European. The discovery calls into question the history of the settlement of Europe and the time frame for the settlement of peoples.

How are viruses different from bacteria

It turns out that bacteria not only took care of the creation of life on our planet, they continue to actively patronize humanity, forcing them to take care of their health and maintain a balance in nature. In an effort to survive themselves, they help the survival of mankind. And even when people decide to go into space, bacteria will follow them.

Distributed everywhere: in the air, in water, in soil, in living organisms. Bacteria have been found even at the bottom of the ocean at a depth of several kilometers, in thermal springs, the water temperature of which reaches 90 degrees, in oil-bearing formations, that is, they are able to exist in conditions where other living organisms do not occur at all.

Thanks to the vital activity of soil bacteria, together with other organisms - plants, fungi - soil fertility is ensured. In 1 gram of black soil contains about 10 billion bacteria. They decompose organic matter left over from dead animals and plants that enter the soil. Due to this, inorganic substances are formed, which can later be used by other organisms, including plants, and carbon dioxide is released, which plants need for photosynthesis. A large amount of humus is formed by bacteria when fertilizing the soil with manure, when cultivating perennial and annual herbaceous plants, in which numerous roots die off. In the presence of oxygen in the soil, bacteria in a short period of time are subjected to the transformation of humus into minerals for plant nutrition, including cultivated ones.

In order to provide better conditions for the vital activity of beneficial soil bacteria in agriculture, soil is cultivated and fertilized. Due to the loosening of the topsoil, moisture is retained and the soil is enriched with air, which is necessary both for the life of cultivated plants and for soil bacteria. Also, the application of manure feeds not only cultivated plants, but also bacteria.

Cyanobacteria and some soil bacteria are able to assimilate nitrogen from the air and convert it into a form available for use by plants. Nodule bacteria are one such group of bacteria. They settle on the roots of legumes and some other plants (sea buckthorn, mulberry). Nodule bacteria are able to assimilate nitrogen from the air and produce organic nitrogen-containing substances, enriching the soil with them.

Assimilated organic substances, bacteria ensure the purification of water bodies. But they can also provoke the reverse process - "water bloom". Cyanobacteria, green and purple sulfur bacteria, together with plants, form the reserves of organic substances in nature, forming them from inorganic compounds. And cyanobacteria also release free oxygen into the atmosphere, which all living creatures breathe. The formation of deposits of natural gas and oil also occurred with the participation of certain types of bacteria.

Life on Earth is impossible without the vital activity of bacteria, since they participate in the cycle of substances in nature, carrying out chemical transformations that are not available to either animals or plants.

The message on the importance of bacteria in human life, summarized in this article, will tell you all about these organisms.

What is the importance of bacteria in nature?

Bacteria of the nodule species can absorb nitrogen from the air and enrich the soil with nitrogen substances. In general, bacteria destroy the complex substances of plant and animal corpses, absorb harmful excretions of organisms and waste. They play the role of orderlies, turning the leaves of shrubs and trees, above-ground shoots of perennials and herbaceous annuals into humus. Bacteria are a powerful biotic factor in nature, as they form not only humus, but also humus.

Speaking about the soil-forming work of bacteria, they created the first soil on the planet. And today its quality is completely dependent on these organisms.

What is the importance of bacteria in human life?

The positive significance of bacteria in human life is that they are used in the food industry. For example: a person makes extensive use of lactic acid bacteria, which feed on sugar in milk and form lactic acid. She, in turn, turns milk into curdled milk, and if it is cream, then into sour cream.

Bacteria are also indispensable in agriculture. With their help, forage is ensiled and vegetables are fermented. Bacterial lactic acid also prevents food and vegetables from decomposing.

Man uses the activity of certain bacteria in the production of drugs, new foods, organic substances. They can produce strong antibiotics that suppress disease-causing organisms.

Negative value of bacteria in human life

Here's another thing about the importance of bacteria in human life - negative. Many of their species cause harm to the national economy, settling on products and spoiling them. There are bacteria that can spoil fishing nets, books and the rarest manuscripts in book depositories.

And for the person himself, they can also be harmful. Botulinum bacteria cause the most dangerous food poisoning, leading to death - botulism. Bacilli accumulate in mushroom and meat products, releasing the poison botulinum.

There are also such types of pathogenic bacteria- salmonella (causes typhoid fever), shigella (causes dysentery), tuberculosis bacillus, clostridium (causes tetanus and gangrene), staphylococci and streptococci.

We hope that the report “The Importance of Bacteria in Human Life” helped you prepare for the lesson. And you can supplement the message "The importance of bacteria in life" through the comment form.

Bacteria are dangerous and useful, their role in human life

Bacterial infections are considered one of the most dangerous - humanity has been fighting pathogenic microorganisms for more than one century. However, not all bacteria are unambiguous enemies for humans. Many species are vital - they ensure proper digestion and even help the immune system defend itself against other microorganisms. MedAboutMe will tell you how to distinguish between bad and good bacteria, what to do if they are found in the analysis, and how to properly treat the diseases they cause.

Bacteria and man

It is believed that bacteria appeared on Earth more than 3.5 billion years ago. It was they who became active participants in creating suitable conditions for life on the planet, and throughout their existence they have been actively involved in important processes. For example, it is thanks to bacteria that the decay of the organic remains of animals and plants occurs. They also created fertile soil on Earth.

And since bacteria live literally everywhere, the human body is no exception. On the skin, mucous membranes, in the gastrointestinal tract, nasopharynx, urogenital tract, there are many microorganisms that interact with humans in different ways.

In the womb, the placenta protects the fetus from the penetration of bacteria, the population of the body occurs in the first days of life:

• The first bacteria the child receives, passing through the birth canal of the mother.
• Microorganisms enter the gastrointestinal tract during feeding breast milk. Here, among more than 700 species, lactobacilli and bifidobacteria predominate (the benefits are described in the table of bacteria at the end of the article).
• The oral cavity is inhabited by staphylococci, streptococci and other microbes, which the child also receives with food and in contact with objects.
• On the skin, the microflora is formed from bacteria that predominate in the people around the child.

The role of bacteria for a person is invaluable, if already in the first months the microflora does not form normally, the child will lag behind in development and often get sick. After all, without symbiosis with bacteria, the body cannot function.

Beneficial and harmful bacteria

Everyone is well aware of the concept of dysbacteriosis - a condition in which the natural microflora in the human body is disturbed. Dysbacteriosis is a serious factor in lowering the immune defense, the development of various inflammations, disruption of the digestive tract and other things. The absence of beneficial bacteria contributes to the reproduction of pathogenic organisms, and fungal infections often develop against the background of dysbacteriosis.

At the same time, many pathogenic microbes live in the environment, which can cause severe illness. The most dangerous are those types of bacteria that in the process of life are capable of producing toxins (exotoxins). It is these substances that are today considered one of the most powerful poisons. Such microorganisms cause dangerous infections:

• Botulism.
• Gas gangrene.
• diphtheria.
• Tetanus.

In addition, the disease can be provoked by bacteria that live in the human body under normal conditions, and when the immune system is weakened, they begin to become more active. The most popular pathogens of this kind are staphylococci and streptococci.

Bacteria life

Bacteria are full-fledged living organisms with a size of 0.5-5 microns, which are able to actively multiply in a suitable environment. Some of them need oxygen, others do not. There are motile and non-motile types of bacteria.

Bacteria cell

Most bacteria living on Earth are single-celled organisms. Mandatory components of any microbe:

• Nucleoid (nucleus-like region containing DNA).
• Ribosomes (carry out the synthesis of proteins).
• Cytoplasmic membrane (separates the cell from the external environment, maintains homeostasis).

Also, some bacterial cells have a thick cell wall, which additionally protects them from damage. Such organisms are more resistant to drugs and antigens that the human immune system produces.

There are bacteria with flagella (mototrichia, lophotrichia, peritrichia), due to which microorganisms are able to move. However, scientists have also recorded another type of movement characteristic of microbes - the sliding of bacteria. Moreover, recent studies show that it is inherent in those species that were previously considered immobile. For example, scientists from the University of Nottingham and Sheffield have shown that methicillin-resistant Staphylococcus aureus (one of the main representatives of the class of superbugs) is able to move without the help of flagella and villi. And this, in turn, significantly affects the understanding of the mechanisms of the spread of a dangerous infection.

Bacterial cells can be of the following forms:

• Round (cocci, from other Greek κόκκος - "grain").
• Rod-shaped (bacilli, clostridia).
• Sinuous (spirochetes, spirilla, vibrios).

Many microorganisms are able to stick together in colonies, so more often scientists and doctors isolate bacteria not by the structure of the element, but by the type of compounds:

• Diplococci are cocci connected in pairs.
• Streptococci are cocci that form chains.
• Staphylococci are cocci that form clusters.
• Streptobacteria are rod-shaped microorganisms connected in a chain.

Reproduction of bacteria

The vast majority of bacteria reproduce by division. The rate of spread of the colony depends on the external conditions and the type of microorganism itself. So, on average, one bacterium is able to divide every 20 minutes - it forms 72 generations of offspring per day. For 1-3 days, the number of descendants of one microorganism can reach several million. In this case, the reproduction of bacteria may not be so fast. For example, the process of division of Mycobacterium tuberculosis takes 14 hours.

If the bacteria enter a favorable environment and have no competitors, the population grows very quickly. Otherwise, its number is regulated by other microorganisms. That is why the human microflora is an essential factor in its protection against various infections.

bacterial spores

One of the features of rod-shaped bacteria is their ability to sporulate. These microorganisms are called bacilli, and they include such pathogenic bacteria:

• The genus Clostridium (cause gas gangrene, botulism, often cause complications during childbirth and after abortion).
• The genus Bacillus (cause anthrax, a number of food poisonings).

Bacterial spores are, in fact, a conserved cell of a microorganism that can survive for a long time without damage, and is practically not subject to various influences. In particular, spores are heat-resistant, not damaged by chemicals. Often the only possible effect is ultraviolet rays, under which the dried bacteria can die.

Bacterial spores are formed when the microorganism enters the unfavourable conditions. It takes approximately 18-20 hours to form inside the cell. At this time, the bacterium loses water, decreases in size, becomes lighter, and a dense shell forms under the outer membrane. In this form, the microorganism can freeze for hundreds of years.

When the spore of a bacterium is exposed to suitable conditions, it begins to germinate into a viable bacterium. The process takes about 4-6 hours.

Types of bacteria

According to the influence of bacteria on humans, they can be divided into three types:

• Pathogenic.
• Conditionally pathogenic.
• Non-pathogenic.

Beneficial bacteria

Non-pathogenic bacteria - those that never lead to disease, even if their numbers are large enough. Among the most famous species, lactic acid bacteria can be distinguished, which are actively used by humans in the food industry - for making cheeses, sour-milk products, dough and much more.

Another important species is bifidobacteria, which are the basis of the intestinal flora. In infants on breastfeeding they make up to 90% of all species living in the gastrointestinal tract. These bacteria for humans perform the following functions:

• Provide physiological protection of the intestine from the penetration of pathogenic organisms.
• They produce organic acids that prevent the reproduction of pathogenic microbes.
• They help to synthesize vitamins (K, group B), as well as proteins.
• Enhance the absorption of vitamin D.

The role of bacteria of this species is difficult to overestimate, because without them normal digestion is impossible, and hence the absorption of nutrients.

Opportunistic bacteria

As part of a healthy microflora, there are bacteria that are classified as opportunistic pathogens. These microorganisms can exist for years on the skin, in the nasopharynx or intestines of a person and not cause infections. However, under any favorable conditions (weakened immunity, microflora disturbances), their colony grows and becomes a real threat.

A classic example of an opportunistic bacterium is Staphylococcus aureus, a microbe that can cause over 100 different diseases, from boils on the skin to deadly blood poisoning (sepsis). At the same time, this bacterium is found in most people in various analyzes, but it still does not cause illness.

Among other representatives of the species of opportunistic microbes:

• Streptococci.
• Escherichia coli.
• Helicobacter pylori (capable of causing ulcers and gastritis, but lives in 90% of people as part of a healthy microflora).

Getting rid of these types of bacteria does not make sense, since they are widespread in the environment. The only adequate way to prevent infections is to strengthen the immune system and protect the body from dysbacteriosis.

Pathogenic bacteria behave differently - their presence in the body always means the development of an infection. Even a small colony can cause harm. Most of these microorganisms secrete two types of toxins:

• Endotoxins are poisons that are formed when cells are destroyed.
• Exotoxins are poisons that bacteria produce during their life. The most dangerous substances for humans that can lead to fatal intoxication.

The treatment of such infections is aimed not only at the destruction of pathogenic bacteria, but also at the removal of the poisoning caused by them. Moreover, in the case of infection with microbes such as tetanus bacillus, it is the introduction of toxoid that is the basis of therapy.

Other known pathogenic bacteria include:

• Salmonella.
• Pseudomonas aeruginosa.
• Gonococcus.
• Pale treponema.
• Shigella.
• Tuberculosis bacillus (Koch's stick).

Classes of bacteria

Today there are many classifications of bacteria. Scientists divide them according to the type of structure, ability to move and other features. However, the Gram classification and the type of breathing remain the most important.

Anaerobic and aerobic bacteria

Among the diversity of bacteria, two large classes are distinguished:

• Anaerobic - those that can do without oxygen.
• Aerobic - those that need oxygen to live.

A feature of anaerobic bacteria is their ability to live in environments where other microorganisms do not survive. The most dangerous in this regard are deep contaminated wounds, in which microbes develop rapidly. The characteristic signs of the growth of the population and life of bacteria in the human body are as follows:

• Progressive tissue necrosis.
• Subcutaneous suppurations.
• Abscesses.
• Internal lesions.

Anaerobes include pathogenic bacteria that cause tetanus, gas gangrene, and toxic lesions of the gastrointestinal tract. Also, the anaerobic class of bacteria includes many opportunistic microbes that live on the skin and in the intestinal tract. They become dangerous if they get into an open wound.

Disease-causing aerobic bacteria include:

• Tuberculosis bacillus.
• Vibrio cholerae.
• Tularemia stick.

The life of bacteria can proceed even with a small amount of oxygen. Such microbes are called facultative aerobic, salmonella and cocci (streptococcus, staphylococcus) are a striking example of the group.

In 1884, Danish physician Hans Gram discovered that different bacteria stained differently when exposed to methylene violet. Some retain color after washing, others lose it. Based on this, the following classes of bacteria were isolated:

• Gram-negative (Gram-) - discoloring.
• Gram-positive (Gram +) - staining.

Staining with aniline dyes is a simple technique that makes it possible to quickly reveal the characteristics of the bacterial membrane wall. For those microbes that do not stain by Gram, it is more powerful and durable, which means that it is more difficult to deal with them. Gram-negative bacteria are primarily more resistant to antibodies produced by the human immune system. This class includes microbes that cause such diseases:

• Syphilis.
• Leptospirosis.
• Chlamydia.
• meningococcal infection.
• Hemophilus infection
• Brucellosis.
• Legionellosis.

The Gram+ class of bacteria includes the following microorganisms:

• Staphylococcus.
• Streptococcus.
• Clostridia (causative agents of botulism and tetanus).
• Listeria.
• Diphtheria stick.

Diagnosis of bacterial infections

Correct and timely diagnosis plays an important role in the treatment of bacterial infections. It is possible to accurately determine the disease only after the analysis, but it can already be suspected by the characteristic symptoms.

Bacteria and viruses: features of bacteria and differences in infections

Most often, a person is faced with acute respiratory diseases. As a rule, cough, rhinitis, fever and sore throat are caused by bacteria and viruses. And although at certain stages of the disease they can manifest themselves in the same way, their therapy will still be radically different.

Bacteria and viruses behave differently in the human body:

• Bacteria are full-fledged living organisms, large enough (up to 5 microns), capable of reproduction in a suitable environment (on mucous membranes, skin, in wounds). Pathogenic microbes secrete poisons that lead to intoxication. The same bacteria can cause infections of different localization. For example, Staphylococcus aureus affects the skin, mucous membranes, and can lead to blood poisoning.
• Viruses are non-cellular infectious agents that can reproduce only inside a living cell, and in the external environment do not manifest themselves as living organisms. At the same time, viruses are always highly specialized and can only infect a specific type of cell. For example, hepatitis viruses can only infect the liver. Viruses are much smaller than bacteria, their size does not exceed 300 nm.

Today, effective drugs have been developed against bacteria -. But these drugs do not act on viruses, moreover, according to the World Health Organization, antibacterial therapy for ARVI worsens the patient's condition.

Symptoms of bacterial infections

Most often, seasonal respiratory infections develop under the influence of bacteria and viruses according to the following scheme:

• The first 4-5 days manifest a viral infection.
• On the 4-5th day, if the rules for the treatment of acute respiratory viral infections were not followed, a bacterial lesion joins.

Symptoms of a bacterial infection in this case will be:

• Deterioration of the patient's condition after improvement.
• High temperature (38°C and above).
• Severe pain in the chest (a sign of the development of pneumonia).
• Discoloration of mucus - greenish, white or yellowish discharge from the nose and in expectorated sputum.
• Rash on the skin.

If it is possible to treat without the involvement of a doctor, since a viral infection resolves itself without complications in 4-7 days, then diseases caused by pathogenic bacteria must be consulted by a therapist or pediatrician.

Other bacterial infections are characterized by the following symptoms:

• General deterioration.
• A pronounced inflammatory process - pain in the affected area, hyperemia, fever.
• Suppuration.

Methods of transmission of bacterial infections

Harmful bacteria enter the human body different ways. The most common ways of infection:

• Airborne.

Bacteria are found in the exhaled air, sputum of the patient, spread by coughing, sneezing and even talking. This route of transmission is typical for respiratory infections, in particular, whooping cough, diphtheria, scarlet fever.

• Contact household.

Microbes get to a person through dishes, door handles, furniture surfaces, towels, phones, toys and more. Also, live bacteria and bacterial spores can stay in the dust for a long time. This is how tuberculosis, diphtheria, dysentery, diseases caused by aureus and other types of staphylococcus aureus are transmitted.

• Alimentary (fecal-oral).

Bacteria enter the body through contaminated food or water. The transmission route is characteristic of gastrointestinal infections, in particular, typhoid fever, cholera, dysentery.

• Sexual.

Infection occurs during sexual intercourse, this is how STIs are transmitted, including syphilis and gonorrhea.

• Vertical.

The bacterium enters the fetus during pregnancy or childbirth. So the child can become infected with tuberculosis, syphilis, leptospirosis.

Deep wounds are dangerous for the development of infections - it is here that anaerobic bacteria, including tetanus bacillus, actively multiply. People with weakened immune systems are also more likely to contract a bacterial infection.

If you suspect the presence of pathogenic bacteria, the doctor may offer the following diagnostic options:

• Smear on flora.

If a respiratory infection is suspected, it is taken from the mucous membranes of the nose and throat. The analysis is also popular for detecting sexually transmitted infections. In this case, the material is taken from the vagina, visceral canal, urethra.

• Bacteriological culture.

It differs from a smear in that the taken biomaterial is not examined immediately, but is placed in an environment favorable for the reproduction of bacteria. After a few days or weeks, depending on the alleged pathogen, the result is evaluated - if there were harmful bacteria in the biomaterial, they grow into a colony. Bakposev is also good because during the analysis, not only the pathogen is determined, but also its quantity, as well as the sensitivity of the microbe to antibiotics.

• Blood test.

A bacterial infection can be detected by the presence of antibodies, antigens in the blood and by the leukocyte formula.

Today, biomaterial is often examined by PCR (polymerase chain reaction), in which infection can be detected even with a small number of microbes.

Positive test and bacterial infections

Since many bacteria are opportunistic and at the same time live in the body, on the mucous membranes and skin of the majority of the population, the results of the analysis must be able to correctly interpret. It must be remembered that the mere presence of bacteria in a person is not a sign of a bacterial infection and is not a reason to start treatment. For example, the norm for Staphylococcus aureus is 103–104. With these indicators, no therapy is required. Moreover, since the microflora of each person is individual, even if the values ​​\u200b\u200bare higher, but there will be no symptoms of the disease, the indicators can also be considered normal.

An analysis for different types of bacteria is prescribed if there are signs of infection:

• Feeling unwell.
• Purulent discharge.
• Inflammatory process.
• Greenish, white or yellow mucus from the nose and in the expectorated sputum.

A positive analysis for bacteria in the absence of symptoms is taken for control if microbes are detected in people from risk groups: pregnant women, children, people in the postoperative period, patients with reduced immunity and concomitant diseases. In this case, it is recommended to take several tests to see the growth dynamics of the colony. If the values ​​do not change, then the immune system is able to control the reproduction of bacteria.

Bacteria in the nasopharynx

Bacteria in the nasopharynx can cause respiratory tract infections. In particular, they are the cause of tonsillitis, bacterial tonsillitis and pharyngitis, as well as sinusitis. Running infections can cause a lot of inconvenience, chronic inflammation, persistent rhinitis, headaches and more. Such diseases are especially dangerous because harmful bacteria can descend through the respiratory tract and affect the lungs - causing pneumonia.

bacteria in urine

Ideally, it is urine that should be free from various microorganisms. The presence of bacteria in the urine may indicate an incorrectly passed analysis (in which microbes got into the material from the surface of the skin and mucous membranes), in which case the doctor asks to be examined again. If the result is confirmed, and the indicator exceeds 104 CFU / ml, bacteriuria (bacteria in the urine) indicates such diseases:

• Kidney damage, in particular, pyelonephritis.
• Cystitis.
• Urethritis.
• Inflammatory process in the urinary canal, for example, as a result of blocking it with a calculus. Observed in urolithiasis.
• Prostatitis or prostate adenoma.

In some cases, bacteria in the urine are found in diseases that are not associated with a local infection. A positive analysis can be with diabetes mellitus, as well as a generalized lesion - sepsis.

Normally, the gastrointestinal tract is inhabited by colonies of various bacteria. In particular, there are:

• Bifidobacteria.
• Lactic acid bacteria (lactobacilli).
• Enterococci.
• Clostridia.
• Streptococci.
• Staphylococci.
• Escherichia coli.

The role of the bacteria that make up the normal microflora is to protect the intestines from infections and ensure normal digestion. Therefore, often the biomaterial from the intestine is examined precisely because of the suspicion of dysbacteriosis, and not for the presence of pathogenic microorganisms.

However, some pathogenic bacteria can cause severe diseases, namely when they enter the gastrointestinal tract. Among these diseases:

• Salmonellosis.
• Cholera.
• Botulism.
• Dysentery.

bacteria on the skin

On the skin, as well as on the mucous membranes of the nasopharynx, in the intestines and genital organs, the balance of microflora is normally established. Bacteria live here - more than 100 species, among which epidermal and Staphylococcus aureus, streptococci are often found. With reduced immunity, and especially in children, they can provoke skin lesions, cause suppuration, boils and carbuncles, streptoderma, panaritium and other diseases.

AT adolescence active reproduction of bacteria leads to acne and acne.

The main danger of microbes on the skin is the possibility of their entry into the bloodstream, wounds and other damage to the epidermis. In this case, harmless microorganisms on the skin can cause serious illness, even cause sepsis.

Diseases caused by bacteria

Bacteria are the cause of infections throughout the body. They affect the respiratory tract, cause inflammatory processes on the skin, cause diseases of the intestines and the genitourinary system.

Diseases of the respiratory tract and lungs

Angina

Angina is an acute lesion of the tonsils. The disease is typical for childhood.

Pathogen:

• Streptococci, rarely staphylococci and other forms of bacteria.

Typical symptoms:

• inflammation of the tonsils with a whitish coating on them, pain when swallowing, hoarseness, high fever, no rhinitis.

Disease risk:

• if a sore throat is not treated well enough, rheumatoid heart disease can become a complication - harmful bacteria spread through the blood and lead to heart valve defects. As a result, heart failure may develop.

Whooping cough is a dangerous infectious disease that mainly affects children. Highly contagious, the bacterium is transmitted by airborne droplets, therefore, without a sufficient level of immunization of the population, epidemics are easily caused.

Pathogen:

• Bordetella pertussis.

Typical symptoms:

• the disease at first proceeds like a common cold, later a characteristic paroxysmal barking cough appears, which may not go away for 2 months, after an attack the child may vomit.

Disease risk:

• Whooping cough is most dangerous for children of the first year of life, as it can cause respiratory arrest and death. Typical complications are pneumonia, bronchitis, false croup. From severe coughing attacks, it is extremely rare for a cerebral hemorrhage or pneumothorax to occur.

Pneumonia

Inflammation of the lungs can be caused by bacteria and viruses, as well as some fungi. Bacterial pneumonia, the most common complication of viral respiratory infections, can develop after the flu. Also, the multiplication of bacteria in the lungs is typical for bedridden patients, the elderly, patients with chronic lung diseases and respiratory disorders, with dehydration.

Pathogen:

• Staphylococci, pneumococci, Pseudomonas aeruginosa and others.

Typical symptoms:

• severe fever (up to 39 ° C and above), cough with copious moist greenish or yellowish sputum, chest pain, shortness of breath, feeling short of breath.

Disease risk:

• depends on the pathogen. With insufficient treatment, respiratory arrest and death are possible.

Tuberculosis

Tuberculosis is one of the most dangerous lung diseases that is difficult to treat. In Russia, tuberculosis has been a socially significant disease since 2004, since the number of infected people is much higher than in developed countries. Back in 2013, up to 54 cases of infection per 100,000 people were recorded.

Pathogen:

• mycobacterium, Koch's bacillus.

Typical symptoms:

• the disease may not manifest itself for a long time, then a cough occurs, a general malaise, a person loses weight, a subfebrile temperature (37-38 ° C) is observed for a month or more, a painful blush. Later, hemoptysis and severe pain appear.

Disease risk:

• features of the bacteria that cause tuberculosis is the development of resistance to antibiotics. Therefore, the infection is difficult to treat and can lead to death or disability. Common complications are heart disease.

Diphtheria is an infectious disease that in 90% of cases affects the upper respiratory tract. Diphtheria is especially dangerous for young children.

Pathogen:

• Corynebacterium diphtheriae (Leffler's bacillus).

Typical symptoms:

• pain when swallowing, hyperemia of the tonsils and specific white films on them, swollen lymph nodes, shortness of breath, high fever, general intoxication of the body.

Disease risk:

• Without timely treatment, diphtheria is fatal. The bacterial cell is capable of producing exotoxin, so the sick person can die from poisoning, in which the heart and nervous system are affected.

Intestinal infections

salmonellosis

Salmonellosis is one of the most common intestinal infections that can occur in different forms. Sometimes bacteria cause severe lesions, but there are times when the disease is mild or no symptoms at all.

Pathogen:

• Salmonella.

Typical symptoms:

• high temperature (up to 38-39 ° C), chills, abdominal pain, vomiting, diarrhea, severe intoxication of the body, in which a person sharply weakens.

Disease risk:

• Depending on the form of the course, in severe infections, bacterial toxins can lead to kidney failure or peritonitis. Children are at risk of dehydration.

Dysentery

Dysentery is an intestinal infection that affects people of all ages. Most often recorded in the summer hot period.

Pathogen:

• 4 types of Shigella bacteria.

Typical symptoms:

• loose stool dark green with impurities of blood and pus, nausea, headaches, loss of appetite.

Disease risk:

• dehydration, which leads to the attachment of various inflammations, as well as intoxication of the body. With proper treatment, good immunity and sufficient fluid intake, the life of Shigella bacteria stops in 7-10 days. Otherwise, a serious complication is possible - intestinal perforation.

Gonorrhea

Gonorrhea is transmitted exclusively through sexual contact, but in rare cases, the infection can be passed from mother to child during childbirth (the baby develops conjunctivitis). The bacteria that causes gonorrhea can grow in the anus or throat, but it most often affects the genitals.

Pathogen:

• Gonococcus.

Typical symptoms:

• possible asymptomatic course of the disease: in men in 20%, in women - more than 50%. In the acute form, there are pains during urination, white-yellow discharge from the penis and vagina, burning and itching.

Disease risk:

• If left untreated, the infection can cause infertility and can also damage the skin, joints, cardiovascular system, liver, and brain.

Syphilis

Syphilis is characterized by slow progression, symptoms appear gradually and do not develop quickly. The characteristic course of the disease is an alternation of exacerbations and remissions. Household infection, many doctors question, in the vast majority of cases, bacteria are transmitted to humans sexually.

Pathogen:

• Pale treponema.

Typical symptoms:

• at the first stage, an ulcer appears on the genitals, which heals on its own in 1-1.5 months, an increase in lymph nodes is observed. After, after 1-3 months, a pale rash appears all over the body, the patient feels weak, the temperature may rise, the symptoms resemble the flu.

Disease risk:

• pathogenic bacteria eventually lead to the development of tertiary syphilis (30% of all infected), which affects the aorta, brain and back, brain, bones and muscles. Perhaps the development of damage to the nervous system - neurosyphilis.

Chlamydia

Chlamydia is a sexually transmitted infection that is often asymptomatic. In addition, pathogenic bacteria are difficult to detect; PCR analysis is prescribed for diagnosis.

Pathogen:

• Chlamydia.

Typical symptoms:

• in the acute form, discharge from the genital organs (usually transparent), pain during urination, blood discharge are observed.

Disease risk:

• in men - inflammation of the epididymis, in women - inflammation of the uterus and appendages, infertility, Reiter's syndrome (inflammation of the urethra).

Meningococcal infection

Meningococcal infection is a group of diseases caused by one pathogen, but occurring in different forms. A person may be an asymptomatic carrier of the bacterium, and in other cases, the microbe causes a generalized infection leading to death.

Pathogen:

• Meningococcus.

Typical symptoms:

• vary with the severity of the disease. The infection can manifest itself as a mild cold, in severe cases, meningococcemia develops, characterized by an acute onset of the disease, the appearance of a red rash (does not disappear with pressure), the temperature rises, confusion is observed.

Disease risk:

• in severe form, tissue necrosis develops, gangrene of the fingers and extremities, and brain damage are possible. With the development of infectious-toxic shock, death quickly occurs.

Tetanus

Tetanus is a dangerous infection that develops in wounds on the skin. The causative agent forms spores of bacteria, in the form of which it is found in the external environment. When it enters the wound, it quickly germinates. Therefore, any serious injury requires the prevention of infection - the introduction of tetanus toxoid.

Pathogen:

• Tetanus stick.

Typical symptoms:

• tetanus affects the central nervous system, at first it is manifested by tonic tension of the jaw muscles (it is difficult for a person to speak, open his mouth), later it spreads to the whole body, the patient arches due to muscle hypertonicity, and at the end respiratory failure develops.

Disease risk:

• the main danger is the toxin that the bacterium secretes, it is he who leads to severe symptoms. As a result of poisoning, tonic tension of all muscles occurs, including the diaphragm and intercostal muscles, as a result of which a person cannot breathe and dies from hypoxia.

Treatment of bacterial diseases

Any bacterial infection needs planned treatment, because bacteria can cause serious damage to the body. Only the doctor chooses the appropriate treatment regimen, which depends not only on the type of disease, but also on the severity of the course.

Antibiotics

Antibiotics are considered the mainstay of treatment for all infections caused by harmful bacteria. Since the discovery of penicillin in the 1920s, many diseases have been moved from fatal to curable. The number of complications after operations has decreased, and, from which every fourth person died, remained dangerous disease only for people at risk.

Modern antibiotics can be divided into two groups:

• Bactericidal - kill pathogenic bacteria.
• Bacteriostatic - slow down the growth, stop the reproduction of bacteria.

The former have a more pronounced effect, however, it is the drugs from the second group that are prescribed more often, since, as a rule, they cause fewer complications.

It is also customary to divide drugs according to the spectrum of action:

• Broad-spectrum antibiotics (penicillins, tetracyclines, macrolides) are used to destroy different types bacteria. They are effective in the case when treatment needs to be started urgently, even before the tests. Penicillins are most commonly prescribed for respiratory bacterial infections.
• Antibiotics that are active against a limited number of bacterial species (often prescribed for tuberculosis and other specific infections).

Any antibiotics must be taken in a course, because if treatment is interrupted, the remaining living bacteria quickly restore the colony.

Problems in the use of antibiotics

Despite the widespread use of antibiotics, doctors today are looking for alternative drugs to treat bacterial infections. This is due to several significant disadvantages of these drugs:

• Development of resistance in bacteria.

Many microorganisms have developed defense mechanisms against drugs, and the use of classical antibiotics is no longer effective. For example, first-generation penicillins, which actively fought against staphylococci and streptococci, are not used today. Staphylococcus aureus has learned to synthesize the enzyme penicillinase, which destroys the antibiotic. Of particular danger are new strains of bacteria that have developed resistance to the latest generation of drugs - the so-called superbugs. The most famous of these is methicillin-resistant Staphylococcus aureus. Also, Pseudomonas aeruginosa and enterococci quickly develop resistance.

• The use of broad-spectrum antibiotics leads to dysbacteriosis.

After such treatment, the balance of microflora is significantly disturbed, complications often develop, the body is weakened not only by the disease, but also by the action of drugs. The use of medicines is limited among certain population groups: pregnant women, children, patients with liver and kidney damage, and other categories.

bacteriophages

An alternative to antibiotics could be bacteriophages, viruses that kill a specific class of bacteria. Among the advantages of such drugs:

• Low likelihood of developing resistance, since bacteriophages are organisms that have lived on Earth for several billion years and continue to infect bacterial cells.
• They do not violate the microflora, since they are specialized medicines - effective only in relation to a specific type of microorganisms.
• Can be used by people at risk.

Preparations containing bacteriophages are already available in pharmacies today. But still, such therapy is losing to antibiotics. Many diseases require immediate treatment, which means that broad-spectrum drugs are needed, while bacteriophages are highly specialized - they can be prescribed only after the pathogen has been identified. In addition, currently known viruses are not able to destroy such a large list of pathogenic bacteria as antibiotics.

Other treatments

WHO does not recommend the use of antibiotics for all types of bacterial infections. In the event that the microbe does not have a high pathogenicity, and the disease proceeds without complications, symptomatic treatment is sufficient - the use of antipyretics, painkillers, vitamin complexes, drinking plenty of water, etc. Often the immune system itself can suppress the reproduction of a colony of pathogenic microorganisms. However, in this case, the patient must be under the supervision of a doctor who will decide on the appropriateness of a particular method of therapy.

Effective vaccines have been developed for many deadly bacterial infections. Vaccinations are recommended for the following diseases:

• Tuberculosis.
• Haemophilus infection.
• Pneumococcal infection.
• Diphtheria (toxoid is used - a vaccine that helps produce antibodies to the toxin of the bacterium).
• Tetanus (toxoid is used).

Bacteria, nutrition and digestion

The live bacteria in foods alone can restore the gut microflora, help the digestive tract, and get rid of toxins. Others, on the contrary, getting into the digestive tract with food, cause dangerous infections and serious poisoning.

• Pathogenic bacteria often multiply in products with violations of storage rules. And breeding anaerobic bacteria are especially dangerous here, which easily increase their numbers even in goods in sealed packaging and canned food.
• Another way of food contamination is through unwashed hands or equipment (knives, cutting boards, etc.). Therefore, food poisoning is easy to get after street food, which was prepared without observing sanitary standards.
• Insufficient heat treatment or its absence also increases the likelihood of the reproduction of various pathogenic forms of bacteria.

Medicines with live bacteria

Preparations with beneficial live bacteria are often recommended by nutritionists for various disorders of the gastrointestinal tract. They help with bloating, flatulence, heaviness, poor digestion of food, frequent poisoning.

In the event that dysbacteriosis is severe, the doctor may recommend a course of drugs to restore microflora.

• Probiotics are products that contain live beneficial bacteria.

The drug is available in capsules with a shell that protects the colonies of microorganisms and helps to deliver them to the intestines in a living form.

• Prebiotics are carbohydrate preparations that contain nutrients for beneficial bacteria.

Such drugs are prescribed if the intestines are inhabited by bifidus and lactobacilli, but their colonies are not large enough.

Lactic acid bacteria are an extensive group of microorganisms that are able to process glucose with the release of lactic acid. In fact, this means that it is precisely these microbes that are involved in the process of fermenting milk - with their help, all fermented milk products are created. Food does not spoil longer precisely thanks to lactic acid bacteria - the acidic environment that they create prevents the growth of pathogens. They exhibit the same protective functions in the human intestine.

The main products in which lactic acid bacteria are present:

• Yogurt without additives.
• Starter cultures, kefir and other fermented milk drinks.
• acidophilus milk.
• Hard cheeses.
• Sauerkraut.

Tables of the main bacteria

Pathogenic bacteria

Bacteria in the table are presented by the main types of microbes that can cause disease. However, many of them also include non-pathogenic or opportunistic bacteria.

Name	bacteria	Type of breath		Diseases caused by bacteria
Staphylococci		Facultative anaerobes		Staphylococcus aureus provokes most purulent diseases. Including: skin lesions, pneumonia, sepsis. Staphylococcus epidermidis causes purulent complications in the postoperative period, and saprophytic - cystitis and urethritis (bacteria are found in the urine).
streptococci		Facultative anaerobes		Scarlet fever, rheumatism (acute rheumatic fever), tonsillitis, pharyngitis, pneumonia, endocarditis, meningitis, abscess.
Clostridia		anaerobic bacteria		Bacteria can be part of a healthy microflora. At the same time, some species are able to secrete the strongest known poison - exotoxin botulinum toxin. Clostridia are the causative agents of tetanus, gas gangrene, and botulism.
		Aerobes, facultative anaerobes		Certain types of bacteria cause anthrax and intestinal infections. The genus also includes Escherichia coli - a representative of healthy microflora.
Enterococci		Facultative anaerobes		Urinary tract infections, endocarditis, meningitis, sepsis.

Beneficial bacteria

The table of bacteria represents the types of microbes that are vital to humans.

Name	bacteria shape	Type of breath	Benefits for the body
bifidobacteria		Anaerobes	Human bacteria, which are part of the intestinal and vaginal microflora, help normalize digestion (drugs with bifidobacteria are prescribed for diarrhea), assimilate vitamins. The peculiarity of bacteria is that they prevent the reproduction of staphylococci, shigella, candida fungus.
	Cocci, sticks	Aerobes requiring reduced oxygen concentration (microaerophilic bacteria)	A group of bacteria that is united by one characteristic - the ability to cause lactic acid fermentation. Used in the food industry, are part of probiotics.

Bacteria, according to scientists, are the most ancient inhabitants of the Earth. They appeared on the planet in time immemorial and for a long time were the only ones on it. Their structure is primitive. These are single-celled organisms, many of which still retain the main features of their ancestors who inhabited the Earth in ancient times. even difficult to assess objectively.

A bunch of

Since the invention of the first powerful microscope (17th century), which makes it possible to examine these small inhabitants of the sea and land, many of them have been discovered. In science, they were separated into a separate group, which is called “bacteria”. Before talking about the importance of bacteria in nature and human life, a few words about them.

A little about bacteria

They may have a different shape. Cocci are spherical, bacilli are rod-shaped, vibrios are like commas, spirilla are spiral, streptococci are a chain, staphylococci are clusters, diplococci are round pairs. All of them are able to move with the help of flagella or in other ways. Bacteria are found everywhere: even in drops of the purest water, in soil, in the air, on stones and skin surfaces. They are also found inside some other organisms, such as humans. Millions of bacteria can live in just one gram of black soil. They are unpretentious and extremely viable: they withstand heating up to 90 degrees, do not die when frozen, rise into the atmosphere up to 30 km, descend deep into the soil for kilometers, live in the depths of the ocean - the real masters of our planet!

The importance of bacteria in nature and human life

The importance of bacteria in nature and human life. Advantages and disadvantages

However, these microscopic organisms are not only our helpers. From them there is also harm to nature and man. Bacteria carry some dangerous diseases: for example, cholera, tuberculosis and many others. They are capable of causing epidemics that can destroy humanity. Even various lethal bacteriological weapons, now banned in the world, have been created. Therefore, a person needs to keep them under constant control.

These materials can be used for the lesson "The Importance of Bacteria in Nature and Human Life" (Grade 6).

The role of bacteria in human life and in nature

Everyone knows that bacteria are the oldest inhabitants of the planet Earth. They appeared, according to scientific data, from three to four billion years ago. And for a long time they were the only and full owners of the Earth. We can say that it all started with bacteria. Roughly speaking, the genealogy of all living organisms is from them. So the role of bacteria in human life and nature (its formation) is very significant.

Ode to bacteria

Their structure is very primitive - for the most part they are unicellular organisms, which, obviously, have changed little over such a very long time. They are unpretentious and can survive in extreme conditions for other organisms (heating up to 90 degrees, freezing, a rarefied atmosphere, the deepest ocean). They live everywhere - in water, soil, underground, in the air, inside other living organisms. And in one gram of soil, for example, hundreds of millions of bacteria can be found. Truly almost ideal creatures that exist next to us. The role of bacteria in human life and nature is great.

Creators of oxygen

Did you know that, most likely, without the existence of these small organisms, we would simply suffocate. Because they (mainly cyanobacteria, capable of releasing oxygen as a result of photosynthesis), due to their abundance, produce a huge amount of oxygen entering the atmosphere. This becomes especially relevant in connection with the deforestation of strategically important forests for the entire Earth. And some other bacteria release carbon dioxide, which is essential for plant respiration. But the role of bacteria in human life and nature is not limited to this. There are several other “activities” for which bacteria can be safely given an honorary diploma!

Orderlies

In nature, one of the functions of bacteria is sanitary. They eat dead cells and organisms, utilizing the unnecessary. It turns out that bacteria for all living things on the planet work as a kind of janitors. In science, this phenomenon is called saprotrophy.

Circulation of substances

And another important role is participation in the circulation of substances on a planetary scale. In nature, all substances pass from organism to organism. Sometimes they are in the atmosphere, sometimes in the soil, maintaining a large-scale cycle. Without bacteria, these ingredients could be concentrated somewhere in one place, and the great cycles would be interrupted. This happens, for example, with a substance such as nitrogen.

Lactic acid products

Milk has long been known to people product. But its long-term storage has become possible only recently with the invention of conservation methods and refrigeration. And since the dawn of cattle breeding, man has unknowingly used bacteria to ferment milk and produce fermented milk products with a longer shelf life than milk itself. So, for example, dry kefir could be stored for months and used as a hearty meal during long transitions through desert areas. In this regard, the role of bacteria in human life is invaluable. After all, if these organisms are “offered” milk, they will be able to produce a lot of tasty and irreplaceable food products from it. Among them: yogurt, curdled milk, fermented baked milk, sour cream, cottage cheese, cheese. Kefir, of course, is made mainly by fungi, but it can’t do without the participation of bacteria.

Great chefs

But the "food-forming" role of bacteria in human life is not limited to fermented milk products. There are many more familiar to us products that are produced with the help of these organisms. This is sauerkraut, salted (barrel) cucumbers, pickles loved by many and other products.

The best neighbors in the world

Bacteria is the most numerous kingdom of animal organisms in nature. They live everywhere - around us, on us, even inside us! And they are very useful "neighbors" for a person. So, for example, bifidobacteria strengthen our immunity, increase the body's resistance to many diseases, help digestion and do a lot of other necessary things. Thus, the role of bacteria in human life as good "neighbors" is just as invaluable.

Production of the necessary substances

Scientists were able to work with bacteria in such a way that as a result they began to secrete substances that are necessary for humans. Often these substances are drugs. So the therapeutic role of bacteria in human life is also great. Some modern medicines are made by them or based on their action.

The role of bacteria in industry

Bacteria are great biochemists! This property is widely used in modern industry. So, for example, in recent decades, biogas production in some countries has reached serious proportions.

Negative and positive role of bacteria

But these microscopic unicellular organisms can be not only helpers of a person and coexist with him in complete harmony and peace. The biggest danger that they are fraught with is infectious diseases caused by bacteria. Settling inside us, poisoning the tissues of our body, they are certainly harmful, sometimes fatal to humans. Among the most famous dangerous diseases caused by bacteria are plague, cholera. Less dangerous are angina and pneumonia, for example. Thus, some bacteria can pose a significant danger to humans if they are pathogenic. Therefore, scientists and doctors of all times and peoples are trying to "keep under control" these harmful microorganisms.

Food spoilage by bacteria

If the meat is rotten, and the soup is sour, for sure, this is the “handiwork” of bacteria! They start up there and actually "eat" these products before us. After that, for a person, these dishes no longer represent nutritional value. It remains only to throw away!

Results

When answering the question of what role bacteria play in human life, both positive and negative points can be distinguished. However, it is obvious that the positive properties of bacteria are much greater than the negative ones. It's all about the reasonable control of man over this numerous kingdom.

What is the importance of bacteria in nature and human life?

What is the importance of bacteria in nature and human life? Give a complete answer... Like a presentation or a story.

Kolya majors

Bacteria play an important role on Earth. They take an active part in the cycle of substances in nature. All organic compounds and a significant part of inorganic ones undergo significant changes with the help of bacteria. This role in nature is of global importance. Appearing on Earth before all organisms (more than 3.5 billion years ago), they created the living shell of the Earth and continue to actively process living and dead organic matter, involving their metabolic products in the circulation of substances. The cycle of substances in nature is the basis for the existence of life on Earth.

The decay of all plant and animal remains and the formation of humus and humus are also produced mainly by bacteria. Bacteria are a powerful biotic factor in nature.

The soil-forming work of bacteria is of great importance. The first soil on our planet was created by bacteria. However, in our time, the condition and quality of the soil depend on the functioning of soil bacteria. Particularly important for soil fertility are the so-called nitrogen-fixing nodule bacteria-symbionts of leguminous plants. They saturate the soil with valuable nitrogen compounds.

Bacteria purify dirty wastewater by breaking down organic matter and converting it into harmless inorganic matter. This property of bacteria is widely used in the operation of wastewater treatment plants.

In many cases, bacteria can be harmful to humans. So, saprotrophic bacteria spoil food products. To protect products from spoilage, they are subjected to special treatment (boiling, sterilization, freezing, drying, chemical cleaning, etc.). If this is not done, food poisoning may occur.

Among bacteria, there are many disease-causing (pathogenic) species that cause diseases in humans, animals or plants. Typhoid fever is caused by the Salmonella bacterium, and dysentery by the Shigella bacterium. Pathogenic bacteria are carried through the air with droplets of the saliva of a sick person when sneezing, coughing, and even during normal conversation (diphtheria, whooping cough). Some disease-causing bacteria are very resistant to desiccation and persist for a long time in the dust (tuberculosis bacillus). Bacteria of the genus Clostridium live in dust and soil - the causative agents of gas gangrene and tetanus. Some bacterial diseases are transmitted through physical contact with a sick person (venereal disease, leprosy). Often, pathogenic bacteria are transmitted to humans through so-called vectors. For example, flies, crawling through sewage, collect thousands of pathogenic bacteria on their paws, and then leave them on the products consumed by humans.

The importance of bacteria in human life and in nature

Goodbye, answers...

Bacteria play an important role in the cycle of substances in nature. Decay bacteria break down organic matter into minerals that plants can use. Bacteria living in the soil ensure its fertility.
Cyanobacteria and soil bacteria assimilate atmospheric nitrogen and enrich the soil with it (nodule bacteria, Azotobacter). The formation of oil and natural gas occurred with the participation of bacteria. Bacteria are used in the food industry - in the souring of milk, the manufacture of yoghurts, cheeses. Antibiotics, vitamins, etc. are obtained from certain groups of microorganisms. Without bacteria, it is impossible to make fibers from flax, silage from green fodder. Bacteria are used in wastewater treatment.
But bacteria can cause great harm to humans and other organisms, causing diseases (tonsillitis, diphtheria, typhus, tuberculosis, and many others). Bacteria can spoil food, releasing toxic substances in the process, and cause disease, such as botulism in humans.
Source 1
Source 2

The importance of bacteria in nature and human life

THE SIGNIFICANCE OF BACTERIA IN NATURE AND HUMAN LIFE
In nature, bacteria are extremely widespread. They inhabit the soil, acting as destroyers organic matter- the remains of dead animals and plants. Transforming organic molecules into inorganic, bacteria thereby cleanse the surface of the planet from decaying residues and return chemical elements and the biological cycle.
The role of bacteria in human life is enormous. Thus, the production of many food and technical products is impossible without the participation of various fermentative bacteria. As a result of the vital activity of bacteria, curdled milk, kefir, cheese, koumiss, as well as enzymes, alcohols, and citric acid are obtained. The processes of fermentation of food products are also associated with bacterial activity.
There are bacteria - symbionts (from the Latin "sim" - together, "bios" - life), which live in the organisms of plants and animals and bring them certain benefits. For example, rhizobia that settle in the roots of some plants are able to assimilate gaseous nitrogen from the soil air and thus supply these plants with the nitrogen necessary for life. When dying, plants enrich the soil with nitrogen compounds, which would be impossible without the participation of such bacteria.
Predatory bacteria are known to eat representatives of other types of prokaryotes.
The negative role of bacteria is also great. Different kinds bacteria cause spoilage of food products, releasing in them products of their metabolism, poisonous to humans. The most dangerous are pathogenic (from the Greek "pathos" - disease and "genesis" - origin) bacteria - the source of various human and animal diseases, such as pneumonia, tuberculosis, appendicitis, salmonellosis, plague, cholera, etc. Bacteria and plants are affected .

Liudmila Sharukhia

1.Positive

1. Soil bacteria are involved in the formation of coal, oil, peat ...
2. Decay bacteria decompose organic matter into minerals that plants can use.
3. Bacteria living in the soil ensure its fertility.
4. Cyanobacteria and soil bacteria assimilate air nitrogen and enrich the soil with it (nodule bacteria, Azotobacter).

1. Bacteria are used in the food industry - in the souring of milk, the manufacture of yoghurts, cheeses.
2. Antibiotics, vitamins, etc. are obtained from certain groups of microorganisms.
3. Without bacteria, it is impossible to make fibers from flax, silage from green fodder
(used in the leather and textile industry).
4. Bacteria are used in wastewater treatment.
2.Negative
A. Importance of bacteria in nature:
1. Pathogenic bacteria cause disease in animals and plants.
B. The importance of bacteria in human life:
1. Bacteria can cause great harm to humans and other organisms, causing diseases (tonsillitis, diphtheria, typhus, tuberculosis, and many others).
2. Bacteria can spoil food, releasing toxic substances in the process, and cause disease, such as botulism in humans.
3. Some bacteria destroy paper, cause metal corrosion.