Presentation on the topic of beneficial and harmful microorganisms. Beneficial and harmful bacteria. What bacteria are the most dangerous to humans. The role of bacteria in nitrogen production

There are many bacteria around us and inside our body. Every day we breathe them in with the air, eat with food, and are a habitat for many. Among them there are useful and not very useful bacteria for any person.

The importance of bacteria in human life

From our knowledge of the benefits and harms of microbes depends on extracting benefits from them and how to protect ourselves from those that harm our body.

Inside our body, harmful and beneficial microbes constantly compete with each other. As a result, we get immunity from many infectious diseases.

At the beginning of life, our body is sterile, and from the very first breath, bacteria begin to colonize the body. With mother's milk in the first hours of life, the baby receives the first beneficial bacteria that populate his intestines and create a special microflora inside him.

The presence of about 40 thousand bacteria in the oral cavity creates its own microflora there, protecting us from gum disease and even from tonsillitis. Some of it is on our skin without harming us. More than 60% of microorganisms live in the stomach and intestines. And when the balance of harmful and beneficial microbes outweighs the harmful ones, many diseases develop, such as ulcers, dysbacteriosis, gastritis and many others.

The importance of beneficial bacteria for our body:

• participate in the process of digestion;
• prevent many infectious diseases;
• used in many drugs;
• participate in the cycle of substances and the supply of our planet with oxygen.

Harmful bacteria lead to:

• infectious diseases;
• food spoilage;
• infection of plants and animals.

To know which are useful and which are not useful bacteria for any person, you need to have an idea about the most significant representatives of both groups.

Beneficial Microorganisms

lactic acid bacteria

A separate group is occupied by lactic acid bacteria: L. Acidophilus, L. Delbrueckii, L. Plantarum, L. Bulgaricus and others.

They are permanent residents of milk and their involvement leads to a range of biochemical processes. Reproducing, they accumulate lactic acid in the fresh product, under the influence of which the milk begins to turn sour. This is how curdled milk is obtained. In production, before getting fermented milk products, milk is pasteurized, then special starter cultures, consisting of bacteria, are added to it. Such dairy products are of high quality and do not contain harmful microbes.

Lactic acid bacteria are used in bread baking, pickling, confectionery production, in the manufacture of soft drinks.

bifidobacteria

These microorganisms live in our intestines and prevent the development of a pathogenic environment for our body in it. To date, 24 strains of bifidobacteria have been identified. Most of all in our intestines B. bifidum, B. infantis, B. Longum, which appear in it in infancy during breastfeeding. In addition to protection, with their help, carbohydrates are fermented in our body, fiber is dissolved and proteins are hydrolyzed. They participate in the synthesis of amino acids, the absorption of calcium and vitamin D. They also regulate the level of acidity.

With their deficiency, dysbacteriosis is observed. With prolonged dysbiosis, the development of such diseases is possible: diarrhea, constipation, gastritis, ulcers, allergies.

coli

The habitat of E. coli is colon. It helps in the breakdown of undigested substances and produces biotin and vitamin K. But, getting into urinary system, causes such diseases: cystitis, urethritis, pyelonephritis.

Streptomycetes

The habitat of Streptomycetaceae is soil, water, organic matter. In nature, they participate in the cycle of substances and in the processing of organic matter. They are widely used in the manufacture of various antibiotics.

Malicious microorganisms

Harmful bacteria harm the body and cause many diseases. At the same time they for a long time can be inside it and wait for immunity to weaken.

Staphylococcus aureus

Carriers of this microorganism are from 25% to 40% of people. It lives on our skin and mucous membranes and is highly resistant to many antibiotics. It is dangerous to humans because it can cause several types of infectious diseases. For a long time, it can be in the human body and wait for the immune system to weaken.

The causative agent of typhoid

The typhoid pathogen Salmonella typhi lives primarily in water, but can multiply on food and milk. It tolerates unfavorable conditions for its development and, getting into our body, causes its intoxication. A person begins to have severe chills, fever, rashes appear on the skin, and the liver enlarges. With untimely treatment, a person dies.

The causative agent of tetanus

Clostridium tetani is considered one of the most dangerous bacteria for humans. Under unfavorable conditions, it forms spores that can stay in the soil for a long time. It enters the body through wounds. Despite the fact that anti-tetanus serum was created back in 1890, up to 60 thousand people die from tetanus every year.

The causative agent of tuberculosis

Mycobacterium tuberculosis is the causative agent of tuberculosis. This species is resistant to many antimicrobials and if it is not detected in time, it leads to the disease of tuberculosis.

plague agent

The carriers of Yersinia pestis are fleas, which, by biting a person, infect him. The rapid spread of the disease leads to an epidemic, from which entire cities died out in the Middle Ages. Thanks to modern medicine, primary signs plague it can be quickly localized. Despite this, up to 3 thousand people die from the plague every year.

Helicobacter pylori

This type of bacteria lives in the human stomach and is resistant to high concentrations acids. For a long time, stomach ulcers were considered a disease of malnutrition and stress. Only in the last century scientists have established true reason gastritis and peptic ulcer. This microorganism is in the stomach of every second inhabitant of the planet. When creating favorable conditions for its life, it begins to multiply rapidly, destroying the gastric mucosa. It is resistant to many antibiotics, and only complex treatment allows you to cope with the disease.

By coexisting with bacteria, it is in our power to get as much benefit as possible from beneficial bacteria. Knowing about the spread of harmful bacteria and applying them in our lives, we are able to protect ourselves from them and from the misuse of antibiotics, which are not always beneficial for our health.

The word "bacteria" in most people is associated with something unpleasant and a threat to health. At best, sour-milk products are remembered. At worst - dysbacteriosis, plague, dysentery and other troubles. Bacteria are everywhere, good and bad. What can microorganisms hide?

What is bacteria

Bacteria in Greek means "stick". This name does not mean that harmful bacteria are meant.

This name was given to them because of the shape. Most of these single cells look like rods. They also come in squares, stellate cells. For a billion years, bacteria do not change their external appearance, they can only change internally. They can be mobile and immobile. Bacteria Outside, it is covered with a thin shell. This allows her to keep her shape. Inside the cell there is no nucleus, chlorophyll. There are ribosomes, vacuoles, outgrowths of the cytoplasm, protoplasm. The largest bacterium was found in 1999. It was called the "Gray Pearl of Namibia". Bacteria and bacillus mean the same thing, only they have a different origin.

Man and bacteria

The appearance of bacteria in the body

A newly born baby has a sterile intestine.

After his first breath, many microorganisms enter the body, with which he was not previously familiar. When the baby is first attached to the breast, the mother transfers beneficial bacteria with milk that will help normalize the intestinal microflora. No wonder doctors insist that the mother immediately after the birth of her child breastfeed him. They also recommend extending such feeding as long as possible.

Beneficial bacteria

Types of harmful bacteria

Harmful bacteria can cause a number of serious diseases in humans. For example, diphtheria, tonsillitis, plague and many others. They are easily transmitted from an infected person through air, food, touch. It is the harmful bacteria, whose names will be given below, that spoil food. They give off an unpleasant odor, rot and decompose, and cause disease.

Names of harmful bacteria

Titles	Habitat	Harm
Mycobacteria	food, water	tuberculosis, leprosy, ulcer
tetanus bacillus
Plague wand
Helicobacter pylori
anthrax bacillus	the soil	anthrax
botulism stick	food, contaminated dishes	poisoning

The most dangerous bacteria

One of the most resistant bacteria is methicillin. It is better known under the name "Staphylococcus aureus" (Staphylococcus aureus). can cause not one, but several infectious diseases. Some types of these bacteria are resistant to powerful antibiotics and antiseptics. Strains of this bacterium can live in the upper respiratory tract, open wounds and urinary tracts of every third inhabitant of the Earth. For a person with strong immunity it poses no danger.

Harmful bacteria to humans are also pathogens called Salmonella typhi. They are the causative agents of acute intestinal infections and typhoid fever. These types of bacteria that are harmful to humans are dangerous because they produce toxic substances that are extremely life-threatening. During the course of the disease, intoxication of the body occurs, a very strong fever, rashes on the body, the liver and spleen increase. The bacterium is highly resistant to various external influences. It lives well in water, on vegetables, fruits and reproduces well in milk products.

And another bacterium that can lead to the death of a person is It causes tuberculosis, which is resistant to drugs. If you do not seek help in a timely manner, a person may die.

Measures to prevent the spread of infections

The second stage is the destruction of the ways through which harmful bacteria can be transmitted. To do this, carry out appropriate propaganda among the population.

For many years, we considered microbes to be dangerous enemies that need to be disposed of, but in fact, everything is not as simple and unambiguous as we used to think.

Microbiologist from Chicago Jack Gilbert decided to find out if the microbes that inhabit our homes are so dangerous. To do this, he explored several houses, including his own.
The specialist came to the same conclusion as many modern scientists. No matter how strange and regrettable it may sound, the main source of bacteria in the house is the person himself. So the fight for the cleanliness of all items in the house is the same as fighting windmills.
Jack found that each person has their own unique set of microbes, and it is enough for them to stay indoors for several hours to leave an easily identifiable bacterial trail - like fingerprints. This discovery will undoubtedly help law enforcement agencies.
However, with regard to the everyday side of the issue, then really dangerous microorganisms in the dwellings of the twenty-first century, Gilbert did not find.
According to the scientist, for so many centuries humanity has become accustomed to living in a dangerous world, when many people died from terrible diseases. When people learned about the nature of bacteria, they began to fight them. Of course, today we live in a much safer and healthier environment. But in their fight against microbes, people often go too far, forgetting that along with harmful ones, there are also useful ones.
“The causes of asthma, allergies, and many other diseases, as studies show, most likely lie in a violation of the microbial balance of the body. This imbalance has been found to be connected even with obesity, autism and schizophrenia!”, says the American scientist.
Another important point is that immediately after cleaning, the clean surface is the first to be inhabited by pathogenic microbes. That is, the more you clean and disinfect, the dirtier and more dangerous the room becomes. Of course, over time, the balance is established when good microbes take their place.
Gilbert is sure that one should not interfere so zealously in natural processes. After research, he himself got three dogs at home to help him and, most importantly, children maintain microbial diversity.

How will you react if you find out that in your body the total weight of bacteria is from 1 to 2.5 kilograms?
Most likely, this will cause surprise and shock. Most people believe that bacteria are dangerous and can cause serious harm to the life of the body. Yes, this is true, but there are, in addition to dangerous, also beneficial bacteria, moreover, vital for human health.

They exist within us, taking a huge part in various processes metabolism. Actively participate in the proper functioning of life processes, both in the internal and external environment of our body. These bacteria include bifidobacteria Rhizobium and E. coli, and many others.

Beneficial bacteria
We live in a world densely populated by bacteria. For example, in a soil layer 30 cm thick and 1 ha in area contains from 1.5 to 30 tons of bacteria. There are almost as many bacteria in each gram of fresh milk as there are people on Earth. They also live inside our body. There are hundreds of different types of bacteria in the human mouth. For every cell in the human body, there are about ten cells of bacteria living in the same body.

Of course, if all these bacteria were harmful to humans, it is unlikely that humans would be able to survive in such an environment. But it turns out that these bacteria are not only not harmful to humans, but, on the contrary, are very beneficial to them.

In a newborn child, the intestinal mucosa is sterile. With the first sip of milk digestive system microscopic “residents” rush to a person, becoming his companions for life. They help a person digest food, produce some vitamins.

Many animals need bacteria to live. For example, plants are known to serve as food for ungulates and rodents. The bulk of any plant is fiber (cellulose). But it turns out that bacteria that live in special sections of the stomach and intestines help animals digest fiber.

We know that putrefactive bacteria spoil food. But this harm that they bring to man is nothing compared to the benefits that they bring to nature as a whole. These bacteria can be called "natural orderlies". By decomposing proteins and amino acids, they support the cycle of substances in nature.

Bacteria help find uses for animal waste. From the millions of tons of liquid manure accumulated on farms, bacteria in special facilities can produce combustible "swamp gas" (methane). Toxic substances contained in the waste are neutralized, in addition, a considerable amount of fuel is produced. Similarly, bacteria purify wastewater.

All living organisms need nitrogen to make proteins. We are surrounded by real oceans of atmospheric nitrogen. But neither plants, nor animals, nor fungi can absorb nitrogen directly from the air. But this can be done by special (nitrogen-fixing) bacteria. Some plants (for example, legumes, sea buckthorn) form special “apartments” (nodules) on their roots for such bacteria. Therefore, alfalfa, peas, lupins and other legumes are often planted on poor or depleted soils so that their bacteria "feed" the soil with nitrogen.

Yogurt, cheese, sour cream, butter, kefir, sauerkraut, pickled vegetables - all these products would not exist if there were no lactic acid bacteria. Man has been using them since ancient times. By the way, curdled milk is digested three times faster than milk - in an hour the body completely digests 90% of this product. Without lactic acid bacteria, there would be no silage for livestock feed.

It is known that if you store wine for a long time, it gradually turns into vinegar. People have probably known about this since they learned how to make wine. But only in the XIX century. Louis Pasteur (see article "Louis Pasteur") established that this transformation is caused by acetic acid bacteria that have entered the wine. They use them to make vinegar.

Various bacteria help a person to make silk, produce coffee, tobacco.
One of the most promising ways to use bacteria was discovered only towards the end of the 20th century. It turns out that it is possible to introduce into the body of a bacterium the gene of any the right person protein (although completely unnecessary bacteria) - for example, the insulin gene. Then the bacterium will begin to produce it. Applied science that makes possible such operations is called genetic engineering. After a long and difficult search, scientists managed to establish a bacterial "production" of this substance (insulin), which is vital for diabetics. In the future, it will probably be possible to turn bacteria into microscopic "factories" for the production of certain proteins on demand.

Margin of safety

Who lives in the gut?

"Wise" Neighbors

Permanent microflora

What are they doing?

Fickle microflora

Location in the gastrointestinal tract

The role of bacteria in nature

Participation in food chains

cyanobacteria

V human body lives more than 2 kilograms of these microscopic creatures! Moreover, most of them do not bring any harm, but live in peace and harmony with the owner of the body. But what are they for? What are the benefits and harms of bacteria to humans?

The role of bacteria living inside us

All microorganisms inhabiting a person from the inside can be divided into two categories:

1. Bacteria that bring tangible benefits to their host. They help a person to absorb and digest food, as well as synthesize useful vitamins. The most well-known bacterium with such properties is Escherichia coli. And the intestinal microflora is inhabited by various bacteroids, lacto- and bifidobacteria. Their benefit is to strengthen the immune system. They also reduce the risk of dangerous microbes entering. Overuse antibiotics or other chemical substances can lead to the death of beneficial bacteria. As a result, dysbacteriosis develops (diarrhea, constipation, nausea) and the human immune system suffers.
   • gonorrhea;
   • whooping cough;
   • diphtheria;
   • cholera;
   • plague and many other diseases.

Once in the body of animals, microbes again bring great harm. They become the source of infection with diseases such as anthrax and brucellosis (and many others). Eating the meat of an infected animal can cause serious harm to human health.

The importance of bacteria in various areas of life

There are many bacterial preparations that help control pests in agriculture and forestry. Some of these microscopic creatures are used for ensiling green fodder. They are used for wastewater treatment special kind bacteria that decompose organic residues and help control the level of pollution in water bodies. And even in modern medicine, microorganisms are actively used for the manufacture of various vitamins, antibiotics and other medicines.

Not all bacteria are beneficial and serve the benefit of people. There are also those that harm food, cause decay of organic matter and produce poison in the process. Eating poor-quality food leads to poisoning of the body. In some cases, the result is even sad - a fatal outcome. To protect yourself and your loved ones from the harm caused by bad bacteria, as well as maintain the natural balance of beneficial creatures in the body, you must:

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Beneficial and harmful bacteria. What bacteria are the most dangerous to humans

The word "bacteria" in most people is associated with something unpleasant and a threat to health. At best, sour-milk products are remembered. At worst - dysbacteriosis, plague, dysentery and other troubles. Bacteria are everywhere, good and bad. What can microorganisms hide?

What is bacteria

Bacteria in Greek means "stick". This name does not mean that harmful bacteria are meant. This name was given to them because of the shape. Most of these single cells look like rods. They also come in the form of triangles, squares, stellate cells. For a billion years, bacteria do not change their external appearance, they can only change internally. They can be mobile and immobile. A bacterium consists of one cell. Outside, it is covered with a thin shell. This allows her to keep her shape. Inside the cell there is no nucleus, chlorophyll. There are ribosomes, vacuoles, outgrowths of the cytoplasm, protoplasm. The largest bacterium was found in 1999. It was called the "Gray Pearl of Namibia". Bacteria and bacillus mean the same thing, only they have a different origin.

Man and bacteria

In our body, there is a constant struggle between harmful and beneficial bacteria. Through this process, a person receives protection from various infections. Various microorganisms surround us at every step. They live on clothes, they fly in the air, they are omnipresent.

The presence of bacteria in the mouth, and this is about forty thousand microorganisms, protects the gums from bleeding, from periodontal disease and even from tonsillitis. If a woman's microflora is disturbed, she may begin gynecological diseases. Compliance with the basic rules of personal hygiene will help to avoid such failures.

Human immunity depends entirely on the state of the microflora. Almost 60% of all bacteria are found in the gastrointestinal tract alone. The rest are located in the respiratory system and in the genital. About two kilograms of bacteria live in a person.

The appearance of bacteria in the body

A newly born baby has a sterile intestine. After his first breath, many microorganisms enter the body, with which he was not previously familiar. When the baby is first attached to the breast, the mother transfers beneficial bacteria with milk that will help normalize the intestinal microflora. No wonder doctors insist that the mother immediately after the birth of her child breastfeed him. They also recommend extending such feeding as long as possible.

Beneficial bacteria

Useful bacteria are: lactic acid, bifidobacteria, E. coli, streptomycents, mycorrhiza, cyanobacteria.

All of them play an important role in human life. Some of them prevent the occurrence of infections, others are used in the production of medicines, and others maintain a balance in the ecosystem of our planet.

Types of harmful bacteria

Harmful bacteria can cause a number of serious diseases in humans. For example, diphtheria, anthrax, tonsillitis, plague and many others. They are easily transmitted from an infected person through air, food, touch. It is the harmful bacteria, whose names will be given below, that spoil food. They give off an unpleasant odor, rot and decompose, and cause diseases.

Bacteria can be gram-positive, gram-negative, rod-shaped.

Names of harmful bacteria

Table. Harmful bacteria for humans. Titles

Titles	Habitat	Harm
Mycobacteria	food, water	tuberculosis, leprosy, ulcer
tetanus bacillus	soil, skin, digestive tract	tetanus, muscle spasms, respiratory failure
Plague wand (considered by experts as a biological weapon)	only in humans, rodents and mammals	bubonic plague, pneumonia, skin infections
Helicobacter pylori	human stomach lining	gastritis, peptic ulcer, produces cytotoxins, ammonia
anthrax bacillus	the soil	anthrax
botulism stick	food, contaminated dishes	poisoning

Harmful bacteria are able to stay in the body for a long time and absorb useful substances from it. However, they can cause an infectious disease.

The most dangerous bacteria

One of the most resistant bacteria is methicillin. It is better known under the name "Staphylococcus aureus" (Staphylococcus aureus). This microorganism is capable of causing not one, but several infectious diseases. Some types of these bacteria are resistant to powerful antibiotics and antiseptics. Strains of this bacterium can live in the upper respiratory tract, open wounds and urinary tracts of every third inhabitant of the Earth. For a person with a strong immune system, this is not dangerous.

Harmful bacteria to humans are also pathogens called Salmonella typhi. They are the causative agents of acute intestinal infections and typhoid fever. These types of bacteria that are harmful to humans are dangerous because they produce toxic substances that are extremely life-threatening. During the course of the disease, intoxication of the body occurs, a very strong fever, rashes on the body, the liver and spleen increase. The bacterium is very resistant to various external influences. It lives well in water, on vegetables, fruits and reproduces well in milk products.

Clostridium tetan is also one of the most dangerous bacteria. It produces a poison called tetanus exotoxin. People who become infected with this pathogen experience terrible pain, convulsions and die very hard. The disease is called tetanus. Despite the fact that the vaccine was created back in 1890, every year on Earth 60 thousand people die from it.

And another bacterium that can lead to human death is Mycobacterium tuberculosis. It causes tuberculosis, which is resistant to drugs. If you do not seek help in a timely manner, a person may die.

Measures to prevent the spread of infections

Harmful bacteria, the names of microorganisms are studied from the student bench by physicians of all directions. Every year, healthcare is looking for new methods to prevent the spread of infections that are dangerous to human life. With the observance of preventive measures, you will not have to waste your energy on finding new ways to deal with such diseases.

To do this, it is necessary to identify the source of the infection in time, determine the circle of patients and possible victims. It is imperative to isolate those who are infected and disinfect the source of infection.

The second stage is the destruction of the ways through which harmful bacteria can be transmitted. To do this, carry out appropriate propaganda among the population.

Food facilities, reservoirs, warehouses with food storage are taken under control.

Each person can resist harmful bacteria in every possible way strengthening their immunity. Healthy lifestyle, observance of elementary hygiene rules, self-protection during sexual contact, use of sterile disposable medical instruments and equipment, complete restriction from communication with quarantined people. When entering the epidemiological region or the focus of infection, it is necessary to strictly comply with all the requirements of the sanitary and epidemiological services. A number of infections are equated in their impact to bacteriological weapons.

Bacteria are beneficial and harmful. Bacteria in human life

Bacteria are the most numerous inhabitants of the planet Earth. They inhabited it in ancient times and continue to exist to this day. Some species have even changed little since then. Good and bad bacteria literally surround us everywhere (and even penetrate into other organisms). With a rather primitive unicellular structure, they are one of the most, probably, effective forms living nature and stand out in a special kingdom.

Margin of safety

These microorganisms, as they say, do not sink in water and do not burn in fire. Literally: withstand temperatures up to plus 90 degrees, freezing, lack of oxygen, pressure - high and low. We can say that nature has invested a huge margin of safety in them.

Bacteria beneficial and harmful to the human body

As a rule, the bacteria that inhabit our bodies in abundance are not given due attention. After all, they are so small that they seem to have no significant significance. Those who think so are largely mistaken. Bacteria useful and harmful have long and reliably “colonized” other organisms and successfully coexist with them. Yes, they cannot be seen without the help of optics, but they can benefit or harm our body.

Who lives in the gut?

Doctors say that if you put together just the bacteria that live in the intestines and weigh it, you get something like three kilograms! With such a huge army it is impossible to ignore. Many of the microorganisms continuously entered the human intestine, but only a few species find favorable conditions for living and living there. And in the process of evolution, they even formed a permanent microflora, which is designed to perform important physiological functions.

"Wise" Neighbors

Bacteria have long played an important role in human life, although until very recently, people did not know about it. They help their host in digestion and perform a number of other functions. What are these invisible neighbors?

Permanent microflora

99% of the population lives permanently in the intestines. They are ardent supporters and helpers of man.

• Essential beneficial bacteria. Names: bifidobacteria and bacteroids. They are the vast majority.
• Associated beneficial bacteria. Names: Escherichia coli, Enterococcus, Lactobacillus. Their number should be 1-9% of the total.

It is also necessary to know that under appropriate negative conditions, all these representatives of the intestinal flora (with the exception of bifidobacteria) can cause diseases.

What are they doing?

The main function of these bacteria is to help us in the process of digestion. It is noticed that a person with improper nutrition can develop dysbacteriosis. As a result, stagnation and poor health, constipation and other inconveniences. With the normalization of a balanced diet, the disease, as a rule, recedes.

Another function of these bacteria is watchdog. They keep track of which bacteria are beneficial. To ensure that "strangers" do not penetrate their community. If, for example, the causative agent of dysentery, Shigella Sonne, tries to enter the intestines, they kill it. However, it is worth noting that this happens only in the body relatively healthy person, With good immunity. Otherwise, the risk of getting sick increases significantly.

Fickle microflora

Approximately 1% in the body of a healthy individual are the so-called opportunistic microbes. They belong to the unstable microflora. Under normal conditions, they perform certain functions that do not harm a person, work for the good. But in a certain situation, they can manifest themselves as pests. These are mainly staphylococci and various kinds of fungi.

Location in the gastrointestinal tract

In fact, the entire digestive tract has a heterogeneous and unstable microflora - beneficial and harmful bacteria. The esophagus contains the same inhabitants as in the oral cavity. In the stomach there are only a few that are resistant to acid: lactobacilli, Helicobacter pylori, streptococci, fungi. In the small intestine, the microflora is also not numerous. Most bacteria are found in the large intestine. So, defecation, a person is able to allocate over 15 trillion microorganisms per day!

The role of bacteria in nature

She is also definitely great. There are several global functions, without which all life on the planet would have ceased to exist long ago. The most important is sanitation. Bacteria eat dead organisms found in nature. They, in essence, work as a kind of janitors, not allowing deposits of dead cells to accumulate. Scientifically they are called saprotrophs.

Another important role of bacteria is participation in the global circulation of substances on land and at sea. On planet Earth, all substances in the biosphere pass from one organism to another. Without some bacteria, this transition would simply be impossible. The role of bacteria is invaluable, for example, in the cycle and reproduction of such important element like nitrogen. There are certain bacteria in the soil that convert the nitrogen in the air into nitrogenous fertilizers for plants (microorganisms live right in their roots). This symbiosis between plants and bacteria is being studied by science.

Participation in food chains

As already mentioned, bacteria are the most numerous inhabitants of the biosphere. And accordingly, they can and should participate in the food chains inherent in the nature of animals and plants. Of course, for a person, for example, bacteria are not the main part of the diet (unless they can be used as food additive). However, there are organisms that feed on bacteria. These organisms, in turn, feed on other animals.

cyanobacteria

These blue-green algae (an outdated name for these bacteria, fundamentally wrong from a scientific point of view) are able to produce huge amounts of oxygen as a result of photosynthesis. Once upon a time, it was they who began to saturate our atmosphere with oxygen. Cyanobacteria continue to do this successfully to this day, forming a certain part of the oxygen in the modern atmosphere!

Bacteria in nature are harmful and beneficial to humans

Most people consider various bacterial organisms solely as harmful particles that can provoke the development of various pathological conditions. Nevertheless, according to scientists, the world of these organisms is very diverse. There are frankly dangerous bacteria that are dangerous to our body, but there are also useful ones - those that provide normal functioning our organs and systems. Let's try to understand a little about these concepts and consider certain types of such organisms. Let's talk about bacteria in nature, harmful and beneficial to humans.

Beneficial bacteria

Scientists say that bacteria became the very first inhabitants of our large planet, and it is thanks to them that there is life on Earth now. Over the course of many millions of years, these organisms gradually adapted to the constantly changing conditions of existence, they changed their appearance and habitat. Bacteria were able to adapt to the surrounding space and were able to develop new and unique life support methods, including multiple biochemical reactions - catalysis, photosynthesis, and even seemingly simple respiration. Now bacteria coexist with human organisms, and such cooperation is distinguished by some harmony, because such organisms can bring real benefits.

After a small person is born, bacteria immediately begin to penetrate into his body. They penetrate through Airways together with air, enter the body along with breast milk, etc. The whole body is saturated with various bacteria.

Their number cannot be accurately calculated, but some scientists boldly say that the number of such organisms is comparable to the number of all cells. The digestive tract alone is home to four hundred varieties of different living bacteria. It is believed that a certain variety of them can grow only in a specific place. So lactic acid bacteria are able to grow and multiply in the intestines, others feel optimal in the oral cavity, and some others live only on the skin.

For many years of coexistence, man and such particles were able to recreate the optimal conditions for cooperation for both groups, which can be characterized as a useful symbiosis. At the same time, bacteria and our body combine their capabilities, while each side remains in the black.

Bacteria are able to collect particles of various cells on their surface, which is why the immune system does not perceive them as hostile and does not attack. However, after organs and systems are exposed to harmful viruses, beneficial bacteria rise to the defense and simply block the path of pathogens. When existing in the digestive tract, such substances also bring tangible benefits. They are engaged in the processing of leftover food, while releasing a significant amount of heat. It, in turn, is transmitted to nearby organs, and is carried throughout the body.

Deficiency of beneficial bacteria in the body or a change in their number causes the development of various pathological conditions. This situation can develop against the background of taking antibiotics, which effectively destroy both harmful and beneficial bacteria. To correct the number of beneficial bacteria, special preparations - probiotics can be consumed.

harmful bacteria

However, it is worth remembering that not all bacteria are human friends. Among them, there are enough dangerous varieties that can only bring harm. Such organisms, after penetrating into our body, cause the development of a variety of bacterial ailments. These are various colds, some varieties of pneumonia, and in addition syphilis, tetanus and other diseases, even deadly ones. There are also diseases of this type that are transmitted by airborne droplets. This is dangerous tuberculosis, whooping cough, etc.

A significant number of diseases provoked by harmful bacteria develop due to the consumption of insufficiently high-quality food, unwashed and unprocessed vegetables and fruits, raw water, and insufficiently fried meat. You can protect yourself from such diseases by observing the norms and rules of hygiene. Examples of such dangerous diseases are dysentery, typhoid fever, etc.

Manifestations of diseases that have developed as a result of an attack of bacteria are the result of the pathological influence of poisons that these organisms produce, or that are formed against the background of their destruction. The human body is able to get rid of them thanks to the natural defense, which is based on the process of phagocytosis of bacteria by white blood cells, as well as on the immune system, which synthesizes antibodies. The latter carry out a bunch of foreign proteins and carbohydrates, and then simply eliminate them from the bloodstream.

Also, harmful bacteria can be destroyed with the help of natural and synthetic medicines, the most famous of which is penicillin. All drugs of this type are antibiotics, they differ depending on active ingredient and from the scheme of action. Some of them are able to destroy the cell membranes of bacteria, while others suspend the processes of their vital activity.

So, in nature there are a lot of bacteria that can bring benefits and harm to humans. Fortunately, the current level of development of medicine makes it possible to cope with the majority of pathological organisms of this kind.

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Benefits and harms of bacteria

The fact is that bacteria are not only harmful, but also undoubtedly beneficial. It is not for nothing that in the intestines of any organism there is a separate environment, which would do well to be isolated into an independent organ, which is called the microflora of the organism. The microflora contains a spectrum of bacteria necessary for normal life.
The role of bacteria in human life is great. Being all in the same intestine, the bacteria break down indigestible food residues in the stomach into organic and inorganic compounds. In the process, amino acids and some vitamins are extracted, which are immediately absorbed into the blood.
Bacteria are also found in dairy products - yogurt, kefir, fermented baked milk. Together with these products, microorganisms enter the gastric tract, where they help the stomach itself cope with its main task - the thorough digestion of food. It is for this reason that we always feel light after taking dairy products and do not feel discomfort in the stomach caused by pain, colic or nausea.
The role of bacteria in human life is great. Being inside the female genital organs, microorganisms create a special acid-base environment, the violation of which leads to a number of unpleasant diseases and inflammation. To maintain such an optimal environment, you need to follow the rules of personal hygiene.
The oral cavity is also full of microbes that allow you to get rid of inflammation and bleeding of the gums, sore throats and periodontal disease.
As you understand, microorganisms are inside our entire body, and it’s not worth getting rid of them so violently. The role of bacteria in human life is ambiguous, but the fact that we need these simple organisms is a hundred percent correct answer.
Drink less antibiotics, which destroy the normal cooperation between microbes and humans, which leads to serious illness.

Tanya

Benefit: Bacteria that provide measurable benefits to their host. They help a person to absorb and digest food, as well as synthesize useful vitamins. The most well-known bacterium with such properties is Escherichia coli. And the intestinal microflora is inhabited by various bacteroids, lacto- and bifidobacteria. Their benefit is to strengthen the immune system. They also reduce the risk of dangerous microbes entering. Excessive use of antibiotics or other chemicals can kill beneficial bacteria. As a result, dysbacteriosis develops (diarrhea, constipation, nausea) and the human immune system suffers.

Sergei

Bacteria harmful to human health. Most often, pathogenic microbes enter the human body through airborne droplets. But this is far from the only way to get infected. Dirty or stale food, bad water, poorly washed hands, various blood-sucking insects (fleas, lice, mosquitoes), a wound on the skin - all this can cause infection with bad microorganisms. Such organisms cause significant harm to health. Namely, they cause serious diseases:

What are the benefits and harms of bacteria

Elena

The harm from bacteria is very noticeable - many bacteria are sources of inflammation and infection. The deadly diseases typhoid and cholera, the serious diseases pneumonia and diphtheria are caused by bacteria, and it is not surprising that people are constantly looking for ways to combat them.
However, many bacteria are beneficial. Bacteria are useful, causing, for example, the fermentation of sweet juices or the ripening of cream. If bacteria did not decompose dead tissue, then the entire surface of the Earth would be covered with it. But most importantly, bacteria are involved in the formation of nitrates, which are necessary for plant life and, consequently, for our life.

Vladimir Kukuruzov

There are microorganisms that indirectly affect human life. They live in soils and water bodies and are engaged in the breakdown of organic waste, ensure the decay of dead plants, saturate the soil with essential minerals and oxygen. Thanks to them, the planet Earth does not lack oxygen.
Even in ancient times, people realized what an invaluable benefit bacteria bring to a person in Everyday life. Many foods cannot be made without the use of beneficial bacteria. Fermented milk products (kefir, yogurt), acetic acid, confectionery, cocoa, coffee are the result of the active life of microorganisms. Even the production of tanned leather or, for example, flax fiber is not complete without their participation.
fermented milk productsThere are many bacterial preparations that help control pests in agriculture and forestry. Some of these microscopic creatures are used for ensiling green fodder. And to purify wastewater, a special type of bacteria is used that decomposes organic residues and helps control the level of pollution of water bodies. And even in modern medicine, microorganisms are actively used for the manufacture of various vitamins, antibiotics and other drugs.
preparation with lactic acid bacteria Not all bacteria are beneficial and serve the benefit of people. There are also those that harm food, cause decay of organic matter and produce poison in the process. Eating poor-quality food leads to poisoning of the body. In some cases, the result is even sad - a fatal outcome. To protect yourself and your loved ones from the harm caused by bad bacteria, as well as maintain the natural balance of beneficial creatures in the body, you must:
Regularly eat fermented milk products enriched with bifido- and lactobacilli.
Eat only fresh and quality products.
Wash your hands before eating and thoroughly wash all fruits and vegetables.
Heat the meat.
Take antibiotics strictly as directed by your doctor. And try not to abuse various medicines. Otherwise, instead of benefit, you can cause significant harm to your health.
Compliance with these simple rules is the key to a healthy life.

How do bacteria enter the human body and what harm do they cause?

Valyusha

from the environment, for example, from dirty hands, towels, through the nose, mouth, skin, who has normal immunity - bacteria, in principle, are not terrible, and who has problems with it - various sores can occur due to bacteria - colds, acne, diarrhea etc.)

Dmitry Kalinkin

There is a hypothesis that all microorganisms are biorobots that perform the functions of repairing tissues, organs, cells, DNA
but not only repair, but also, in general, a change in the internal state of living beings, people, animals and plants, as well as unicellular ones. Viruses, like the smallest biorobots, are engaged in changes at the genetic level.
At the most rough level, helmpints are used.
That is, all microorganisms are a tool for managing the internal state complex organisms from the control function of NATURE. There is even a playful hypothesis that viruses are the driving force behind the evolution of living beings, which forced all living things to develop in order to ensure the life of viruses. (After all, they cannot live on their own.

Grigory Miroshin

Eternity…………

The danger of bacterial diseases was greatly reduced at the end of the 19th century with the invention of the vaccination method, and in the middle of the 20th century with the discovery of antibiotics.

useful; For thousands of years, humans have used lactic acid bacteria to produce cheese, yogurt, kefir, vinegar, and fermentation.

At present, methods have been developed for the use of phyto pathogenic bacteria as safe herbicides, entomopathogenic - instead of insecticides. The most widely used is Bacillus thuringiensis, which produces toxins (Cry-toxins) that act on insects. In addition to bacterial insecticides, bacterial fertilizers have found application in agriculture.

Bacteria that cause human disease are being used as biological weapons.

Thanks to rapid growth and reproduction, as well as the simplicity of the structure, bacteria are actively used in scientific research in molecular biology, genetics, genetic engineering and biochemistry. Escherichia coli has become the best studied bacterium. Information about the processes of bacterial metabolism made it possible to produce bacterial synthesis of vitamins, hormones, enzymes, antibiotics, etc.

A promising direction is the enrichment of ores with the help of sulfur-oxidizing bacteria, the purification of soils and reservoirs contaminated with oil products or xenobiotics by bacteria.

Normally, from 300 to 1000 species of bacteria with a total weight of up to 1 kg live in the human intestine, and the number of their cells is an order of magnitude greater than the number of cells in the human body. They play an important role in the digestion of carbohydrates, synthesize vitamins, and displace pathogenic bacteria. It can be figuratively said that the human microflora is an additional "organ", which is responsible for protecting the body from infections and digestion.

it's not very short. but I think you can cut it however you like.

Karim Murotaliyev

Bacteria and man have coexisted with each other for millenniums. They bring enormous benefits to a person. Beneficial bacteria make up 99% of the total population that inhabit the human body and only 1% of them have a bad reputation. Due to the harm that bacteria cause to humans, any mention of them causes negative emotions. Bacteria are found in the air we breathe, in soil, in food and water, in plants, in our body, etc.

Rice. 1. Bacteria and man.

The first bacteria on planet Earth appeared billions of years ago, long before the appearance of plants, animals and humans. For millions of years, they, changing their habitat in an unfavorable climate, changed themselves, gradually improving their means of life support, and eventually populated the entire planet: oceans, soil, rocks, volcanoes and arctic ice. The survival of bacteria was ensured by the presence of "jumping" genes, which they learned to pass on to each other along with the acquired achievements.

Rice. 2. Microbes are the real invisible masters of the Earth.

Rice. 3. About 70% of the living beings of the Earth are bacteria.

Bacteria and man: benefits for the human body

Bacteria have been living on planet Earth for more than 3.5 billion years. During this time they have learned a lot and adapted to a lot. Now they are helping people. Bacteria and man became inseparable. As scientists have calculated, the human body contains from 500 to 1000 different types of bacteria or trillions of these amazing tenants, which is up to 4 kg of total weight. Up to 3 kilograms of microbial bodies is found only in the intestines. The rest of them are in urinary tract, on the skin and other cavities of the human body.

The human body is inhabited by both beneficial and harmful bacteria. The existing balance between the human body and bacteria has been polished for centuries. With a decrease in immunity, "bad" bacteria cause great harm to the human body. In some diseases, the process of replenishing the body with “good” bacteria is difficult.

Rice. 4. Bacteria inhabiting the oral cavity: Streptococcus mutants (green). Bacteroides gingivalis, causes periodontitis (purple). Candida albicus (yellow).

Rice. 5. Inner surface large intestine. Pink islets are clusters of bacteria.

Rice. 6. Bacteria in duodenum(marked in red).

Rice. 7. Bacteria (blue and green) on human skin (computer image).

Microbes fill the body of a newborn from the first minutes of his life and finally form the composition of the intestinal microflora by 10-13 years. In the intestine live streptococci, lactobacilli, bifidobacteria, enterobacteria, fungi, intestinal viruses, non-pathogenic protozoa. Lactobacilli and bifidobacteria make up 60% of the intestinal flora. The composition of this group of bacteria is always constant, numerous and performs the main functions.

Rice. 12. Intestinal bacteria (red) in the duodenum.

A person owes the normal functioning of the body to bifidobacteria, lactobacilli, enterococci, Escherichia coli and bacteriods, which account for 99% normal microflora intestines. 1% are representatives of opportunistic flora: clostridia, Pseudomonas aeruginosa, staphylococcus, proteus, etc.

bifidobacteria

• thanks to bifidobacteria, acetate and lactic acid are produced. By acidifying the habitat, they inhibit the growth of pathogenic bacteria that cause decay and fermentation;
• thanks to bifidobacteria, the risk of developing food allergies in babies is reduced;
• they provide an antioxidant and antitumor effect;
• bifidobacteria are involved in the synthesis of vitamin C;
• bifido- and lactobacilli are involved in the absorption of vitamin D, calcium and iron.

Rice. 13. Bifidobacteria. 3D image.

coli

• Special attention is paid to the representative of this genus Escherichia coli M17. It is able to produce the substance cocilin, which inhibits the growth of a number of pathogenic microbes.
• With the participation of Escherichia coli, vitamins K, group B (B1, B2, B5, B6, B7, B9 and B12), folic and nicotinic acids are synthesized.

Rice. 14. E. coli. 3D image.

Rice. 15. Escherichia coli under a microscope.

Enterobacteria

Enterobacteria are actively involved in the restoration of intestinal microflora after taking antibiotics.

lactobacilli

Lactobacilli inhibit the growth of putrefactive and conditionally pathogenic microorganisms due to the formation of a number of antimicrobial substances.

Rice. 16. Lactobacilli (3D image).

The positive role of bacteria in the human body

• With the participation of bifido-, lacto- and enterobacteria, vitamins K, C, group B (B1, B2, B5, B6, B7, B9 and B12), folic and nicotinic acids are synthesized.
• Thanks to the intestinal microflora, undigested food components from the upper intestines are broken down - starch, cellulose, protein and fat fractions.
• The intestinal microflora maintains water-salt metabolism and ionic homeostasis.
• Due to the secretion of special substances, the intestinal microflora inhibits the growth of pathogenic bacteria that cause putrefaction and fermentation.
• Bifido-, lacto- and enterobacteria take part in the detoxification of substances that enter from the outside and are formed inside the body itself.
• The intestinal microflora plays an important role in restoring local immunity. Thanks to it, the number of lymphocytes, the activity of phagocytes and the production of immunoglobulin A increase.
• Thanks to the intestinal microflora, the development of the lymphoid apparatus is stimulated.
• Increases the resistance of the intestinal epithelium to carcinogens.
• Microflora protect the intestinal mucosa and provide energy to the intestinal epithelium.
• Regulates intestinal peristalsis.
• The intestinal flora acquires the skills to capture and remove viruses from the host organism, with which it has been in symbiosis for many years.
• Maintains the body's thermal balance. The microflora feeds on substances that are not digested by the enzymatic system of substances coming from the upper sections. gastrointestinal tract. As a result of complex biochemical reactions, a huge amount of thermal energy is produced. Heat is carried throughout the body with blood flow and enters all internal organs. That is why a person always freezes when starving.
• Regulates the reabsorption of components of bile acids (cholesterol), hormones, etc.

Rice. 17. Lactobacillus and Bifidobacterium bifidum cells.

Rice. 18. E. coli.

In diseases that reduce the body's immunity, intestinal diseases, long-term use antibacterial drugs and in the absence of lactose in the human body, when the sugar contained in milk is not digested and begins to ferment in the intestines, changing the acid balance of the intestines, a microbial imbalance occurs - dysbacteriosis (dysbiosis). Dysbacteriosis is characterized by the death of "good" bacteria and the increased growth of pathogenic microorganisms and fungi. In the intestines, the processes of putrefaction and fermentation begin to prevail. This is manifested by diarrhea and bloating, pain, loss of appetite, and then weight, children begin to lag behind in development, anemia and hypovitaminosis develop.

Bacteria and man will always coexist together. The health of every person is in his hands. If a person takes care of himself, then he will remain healthy, which means happy for many years.

Rice. 19. Bacteria and man. Together forever.

Many types of bacteria are useful and successfully used by humans.

Firstly, beneficial bacteria are widely used in the food industry.

In the production of cheese, kefir, cream, milk coagulation is necessary, which occurs under the action of lactic acid. Lactic acid is produced by lactic acid bacteria, which are part of the starter cultures and feed on the sugar contained in milk. Lactic acid itself promotes the absorption of iron, calcium, phosphorus. These beneficial elements help us fight infectious diseases.

In the production of cheese, it is pressed into pieces (heads). The cheese heads are sent to the ripening chambers, where the activity of various lactic and propionic acid bacteria included in its composition begins. As a result of their activity, the cheese "ripens" - it acquires a characteristic taste, smell, pattern and color.

For the production of kefir, a starter containing lactic acid bacilli and lactic acid streptococci is used.

Yogurt is a tasty and healthy fermented milk product. Milk for the production of yogurt must be of very high quality. It should have a minimum amount of harmful bacteria that can interfere with the development of beneficial yogurt bacteria. Yoghurt bacteria convert milk into yogurt and give it a distinctive flavor.

Rice. 14. Lactobacilli - lactic acid bacteria.

Lactic acid and yogurt bacteria entering the human body with food help to fight not only harmful bacteria in the intestines, but also viruses that cause colds and other infections. In the course of their life, these beneficial bacteria create such an acidic environment (due to the excreted metabolic products) that only a microbe very adapted to difficult conditions, such as E. coli, can survive next to them.

The activity of beneficial bacteria is used in the fermentation of cabbage and other vegetables.

Secondly, bacteria are used to leach ores in the extraction of copper, zinc, nickel, uranium and other metals from natural ores. Leaching is the extraction of minerals from ore that is not rich in them with the help of bacteria, when other methods of obtaining (for example, smelting the ore) are inefficient and expensive. Leaching is carried out by aerobic bacteria.

Thirdly, beneficial aerobic bacteria are used to clean wastewater from cities and industrial enterprises from organic remains.

The main purpose of such biological treatment is the neutralization of complex and insoluble organic substances of wastewater that cannot be extracted from it by mechanical treatment, and their decomposition into simple water-soluble elements.

Fourth, bacteria are used in the production of silk and leather processing, etc. Raw materials for the manufacture of artificial silk are produced by special transgenic bacteria. Technical lactic acid bacteria are used in the leather industry for swelling and deashing (treatment of raw materials from solid compounds), in the textile industry, as an auxiliary agent for dyeing and printing.

Fifth, bacteria are used to control agricultural pests. Agricultural plants are treated with special preparations that contain certain types bacteria. Insects - pests, absorbing parts of plants treated with biological products, swallow bacterial spores with food. This leads to the death of pests.

sixth, bacteria are used to produce various medicines (for example, interferon) that kill viruses and support human immunity (protection).

And the last, harmful bacteria also have beneficial properties.

Decay bacteria (coprophytic bacteria) destroy the corpses of dead animals, leaves of trees and shrubs that have fallen to the ground, and the trunks of dead trees themselves. These bacteria are a kind of orderlies of our planet. They feed on organic matter and turn it into humus - a fertile layer of the earth.

Soil bacteria live in the soil and also provide many benefits in nature. mineral salts, which are produced by soil bacteria, are then absorbed from the soil by plant roots. One cubic centimeter of the surface layer of forest soil contains hundreds of millions of soil bacteria.

Rice. 15. Clostridia - soil bacteria.

Bacteria also live in the soil, which absorb nitrogen from the air, accumulating it in their body. This nitrogen is then converted into proteins. After the death of bacterial cells, these proteins turn into nitrogenous compounds (nitrates), which are fertilizer and are well absorbed by plants.

Conclusion.

Bacteria are a large, well-studied group of microorganisms. Bacteria are found everywhere and a person meets with them in his life all the time. Bacteria can be beneficial to humans, and can become a source of dangerous diseases.

The study of the properties of bacteria, the fight against their harmful manifestations and the use of the beneficial properties of the vital activity of bacteria is one of the main tasks for humans.

6th grade student B _________________________________ / Yaroslav Shchipanov /

Literature.

1. Berkinblit M.B., Glagolev S.M., Maleeva Yu.V., Biology: Textbook for grade 6. – M.: Binom. Knowledge Lab, 2008.

2. Ivchenko, T. V. Electronic textbook"Biology: 6th grade. Living organism". // Biology at school. - 2007.

3. Pasechnik V.V. Biology. 6 cells Bacteria, fungi, plants: Proc. for general education textbook establishments, - 4th ed., stereotype. – M.: Bustard, 2000.

4. Smelova, V.G. Digital microscope at the lessons of biology // Publishing House "First of September" Biology. - 2012. - No. 1.

Bacteria appeared about 3.5-3.9 billion years ago, they were the first living organisms on our planet. Over time, life developed and became more complex - new, each time more complex forms of organisms appeared. Bacteria all this time did not stand aside, on the contrary, they were the most important component of the evolutionary process. It was they who were the first to develop new forms of life support, such as respiration, fermentation, photosynthesis, catalysis ... and also found effective ways to coexist with almost every living being. Man is no exception.

But bacteria is a whole domain of organisms, with over 10,000 species. Each species is unique and followed its own evolutionary path, as a result, developed its own unique shapes coexistence with other organisms. Some bacteria went into close mutually beneficial cooperation with humans, animals and other creatures - they can be called useful. Other species have learned to exist at the expense of others, using the energy and resources of donor organisms - they are commonly considered harmful or pathogenic. Still others have gone even further and have become practically self-sufficient, they receive everything they need for life from the environment.

Inside a man, as well as inside other mammals, lives unimaginably a large number of bacteria. There are 10 times more of them in our bodies than all the cells of the body combined. Among them, the vast majority are useful, but the paradox is that their vital activity, their presence inside us is a normal state of affairs, they depend on us, we, in turn, on them, and at the same time we do not feel any signs of this cooperation. Another thing is harmful, for example, pathogenic bacteria, once inside us, their presence immediately becomes noticeable, and the consequences of their activity can become very serious.

Beneficial bacteria

The vast majority of them are creatures living in symbiotic or mutualistic relationships with donor organisms (in which they live). Usually, such bacteria take on some of the functions that the host organism is not capable of. An example is the bacteria that live in the human digestive tract and process part of the food that the stomach itself is not able to cope with.

Some types of beneficial bacteria:

Escherichia coli (lat. Escherichia coli)

It is an integral part of the intestinal flora of humans and most animals. Its benefits can hardly be overestimated: it breaks down indigestible monosaccharides, promoting digestion; synthesizes vitamins of group K; prevents the development of pathogenic and pathogenic microorganisms in the intestine.

Closeup: colony of bacteria Escherichia coli

Lactic acid bacteria (Lactococcus lactis, Lactobacillus acidophilus, etc.)

Representatives of this order are present in milk, dairy and fermented products, and at the same time are part of the microflora of the intestines and oral cavity. Able to ferment carbohydrates and in particular lactose and produce lactic acid, which is the main source of carbohydrates for humans. By maintaining a constantly acidic environment, the growth of unfavorable bacteria is inhibited.

bifidobacteria

Bifidobacteria have the most significant effect on infants and mammals, accounting for up to 90% of their intestinal microflora. Through the production of lactic and acetic acids, they completely prevent the development of putrefactive and pathogenic microbes in the child's body. In addition, bifidobacteria: contribute to the digestion of carbohydrates; protect the intestinal barrier from the penetration of microbes and toxins into the internal environment of the body; synthesize various amino acids and proteins, vitamins of groups K and B, beneficial acids; promote intestinal absorption of calcium, iron and vitamin D.

Harmful (pathogenic) bacteria

Some types of pathogenic bacteria:

Salmonella Typhi

This bacterium is the causative agent of a very acute intestinal infection, typhoid fever. Salmonella typhi produces toxins that are dangerous only for humans. When infected, a general intoxication of the body occurs, which leads to severe fever, a rash all over the body, in severe cases- to the defeat of the lymphatic system and as a result to death. Every year, 20 million cases of typhoid fever are recorded in the world, 1% of cases lead to death.

Salmonella typhi bacteria colony

Tetanus bacillus (Clostridium tetani)

This bacterium is one of the most persistent and at the same time the most dangerous in the world. Clostridium tetani produces an extremely toxic poison, a tetanus exotoxin, resulting in almost complete defeat nervous system. People who become ill with tetanus experience the most terrible torment: all the muscles of the body spontaneously strain to the limit, powerful convulsions occur. Mortality is extremely high - on average, about 50% of those infected die. Fortunately, back in 1890, the tetanus vaccine was invented, it is given to newborns in all developed countries of the world. In underdeveloped countries, tetanus kills 60,000 people every year.

Mycobacteria (Mycobacterium tuberculosis, Mycobacterium leprae, etc.)

Mycobacteria are a family of bacteria, some of which are pathogenic. Various members of this family cause such dangerous diseases like tuberculosis, mycobacteriosis, leprosy (leprosy) - they are all transmitted by airborne droplets. Mycobacteria cause more than 5 million deaths each year.

The totality of bacteria that inhabit the human body has a common name - the microbiota. In a normal, healthy human microflora, there are several million bacteria. Each of them plays an important role for the normal functioning of the human body.

In the absence of any type of beneficial bacteria, a person begins to get sick, the work of the gastrointestinal tract and respiratory tract is disrupted. Beneficial bacteria for humans are concentrated on the skin, in the intestines, on the mucous membranes of the body. The number of microorganisms is regulated by the immune system.

Normally, the human body contains both beneficial and pathogenic microflora. Bacteria can be beneficial or pathogenic.

There are many more beneficial bacteria. They make up 99% of the total number of microorganisms.

In this position, the necessary balance is maintained.

Among the different types of bacteria that live on the human body, we can distinguish:

• bifidobacteria;
• lactobacilli;
• enterococci;
• coli.

bifidobacteria

This type of microorganisms is the most common, involved in the production of lactic acid and acetate. It creates an acidic environment, thereby neutralizing most pathogenic microbes. Pathogenic flora ceases to develop and cause the processes of decay and fermentation.

Bifidobacteria play an important role in the life of a child, as they are responsible for the presence of an allergic reaction to any food. In addition, they have an antioxidant effect, prevent the development of tumors.

The synthesis of vitamin C is not complete without the participation of bifidobacteria. In addition, there is information that bifidobacteria help to absorb vitamins D and B, which are necessary for a person for normal life. In the presence of a deficiency of bifidobacteria, even taking synthetic vitamins this group will not bring any result.

lactobacilli

This group of microorganisms is also important for human health. Due to their interaction with other inhabitants of the intestine, the growth and development of pathogenic microorganisms is blocked, pathogens are suppressed. intestinal infections.

Lactobacilli are involved in the formation of lactic acid, lysocin, bacteriocins. This is a great help to the immune system. If there is a deficiency of these bacteria in the intestine, then dysbacteriosis develops very quickly.

Lactobacilli colonize not only the intestines, but also the mucous membranes. So these microorganisms are important for women's health. They maintain the acidity of the vaginal environment, do not allow the development of bacterial vaginosis.

coli

Not all types of E. coli are pathogenic. Most of them do the opposite. protective function. The usefulness of the genus Escherichia coli lies in the synthesis of cocilin, which actively resists the bulk of pathogenic microflora.

These bacteria are useful for the synthesis of different groups of vitamins, folic and nicotinic acid. Their role in health should not be underestimated. For example, folic acid is essential for the production of red blood cells and maintenance normal level hemoglobin.

Enterococci

This type of microorganism colonizes the human intestine immediately after birth.

They help digest sucrose. Living mainly in the small intestine, they, like other beneficial non-pathogenic bacteria, provide protection against excessive reproduction of harmful elements. At the same time, enterococci are conditionally safe bacteria.

If they begin to exceed the permissible norms, various bacterial diseases. The list of diseases is very large. Ranging from intestinal infections, ending with meningococcal.

The positive effect of bacteria on the body

The beneficial properties of non-pathogenic bacteria are very diverse. As long as there is a balance between the inhabitants of the intestines and mucous membranes, the human body functions normally.

Most bacteria are involved in the synthesis and breakdown of vitamins. Without their presence, B vitamins are not absorbed by the intestines, which leads to disorders of the nervous system, skin diseases, and a decrease in hemoglobin.

The bulk of undigested food components that have reached the large intestine are broken down precisely due to bacteria. In addition, microorganisms ensure the constancy of water-salt metabolism. More than half of the entire microflora is involved in the regulation of absorption fatty acids, hormones.

The intestinal microflora forms local immunity. It is here that the destruction of the bulk of pathogenic organisms takes place, the harmful microbe is blocked.

Accordingly, people do not feel bloating and flatulence. An increase in lymphocytes provokes active phagocytes to fight the enemy, stimulate the production of immunoglobulin A.

Useful not pathogenic microorganisms have a positive effect on the walls of the small and large intestines. They maintain a constant level of acidity there, stimulate the lymphoid apparatus, the epithelium becomes resistant to various carcinogens.

Intestinal peristalsis also largely depends on what microorganisms are in it. Suppression of the processes of decay and fermentation is one of the main tasks of bifidobacteria. Many microorganisms for many years develop in symbiosis with pathogenic bacteria, thereby controlling them.

Biochemical reactions that constantly occur with bacteria release a lot of heat energy, maintaining the overall heat balance of the body. Microorganisms feed on undigested residues.

Dysbacteriosis

Dysbacteriosis is a change in the quantitative and qualitative composition of bacteria in the human body . Wherein beneficial organisms die, and malicious actively multiply.

Dysbacteriosis affects not only the intestines, but also mucous membranes (there may be dysbacteriosis of the oral cavity, vagina). In the analyzes, the names will prevail: streptococcus, staphylococcus, micrococcus.

V normal condition beneficial bacteria regulate the development of pathogenic microflora. Skin, respiratory organs are usually under reliable protection. When the balance is disturbed, a person feels the following symptoms: intestinal flatulence, bloating, abdominal pain, upset.

Later, weight loss, anemia, vitamin deficiency may begin. From the reproductive system, abundant discharge is observed, often accompanied by bad smell. Irritations, roughness, cracks appear on the skin. Dysbacteriosis side effect after taking antibiotics.

Upon detection similar symptoms you must definitely consult a doctor who will prescribe a set of measures to restore normal microflora. This often requires taking probiotics.

In addition to harmful, there are beneficial bacteria that provide the body with great help.

For the layman, the term "bacteria" is most often associated with something harmful and life-threatening.

Most often, among the beneficial bacteria, lactic-acid microorganisms are recalled.

If we talk about harmful bacteria, then people most often remember such diseases as:

• dysbacteriosis;
• plague;
• dysentery and some others.

Beneficial bacteria for humans help to carry out some biochemical processes in the body that ensure normal life.

Bacterial microorganisms live almost everywhere. They are found in air, water, soil, in any type of tissue, both living and dead.

A harmful microorganism can cause serious harm to the body, and the resulting pathologies can seriously undermine the state of health.

The list of the most famous pathogenic microbes includes:

1. Salmonella.
2. Staphylococcus.
3. Streptococcus.
4. Vibrio cholerae.
5. Plague wand and some others.

If harmful microorganisms are known to most people, then not everyone knows about beneficial bacterial microorganisms, and those people who have heard about the presence of beneficial bacteria are unlikely to be able to name them and how they are useful to humans.

Depending on the impact on humans, the microflora can be divided into three groups of microorganisms:

• pathogenic;
• conditionally pathogenic;
• non-pathogenic.

Non-pathogenic microorganisms are the most useful for humans, pathogenic ones are the most harmful, and conditionally pathogenic microorganisms can be beneficial under certain conditions, and become harmful when external conditions change.

In the body, beneficial and harmful bacteria are in balance, but when some factors change, the predominance of pathogenic flora can be observed, which leads to the development of various ailments.

Beneficial bacteria for humans

The most useful for the human body are sour-milk and bifidobacteria.

These types of bacteria are not capable of leading to the development of diseases in the body.

Beneficial bacteria for the intestines are a group of lactic acid bacteria and bifidobacteria.

Beneficial microbes - lactic acid bacteria are used in the production of a variety of products from milk. In addition, they can be used in the preparation of dough and some other types of products.

Bifidobacteria form the basis of the intestinal flora in the human body. For young children who are on breastfeeding this variety of microorganisms makes up to 90% of all types of bacteria living in the intestines.

These bacteria are entrusted with the performance of a large number of functions, the main among which are the following:

1. Ensuring the physiological protection of the digestive tract from penetration and damage by pathogenic microflora.
2. Provides the production of organic acids. Preventing the reproduction of pathogenic organisms.
3. They participate in the synthesis of B vitamins and vitamin K, in addition, they participate in the process of protein synthesis necessary for the human body.
4. Accelerates the absorption of vitamin D.

Bacteria useful to humans perform a huge number of functions and their role is difficult to overestimate. Without their participation, it is impossible to carry out normal digestion and absorption of nutrients.

The colonization of the intestines with beneficial bacteria occurs in the first days of a baby's life.

Bacteria penetrate the baby's stomach and begin to participate in all digestive processes that occur in the body of the newborn.

In addition to sour-milk and bifidobacteria, Escherichia coli, streptomycetes, mycorrhiza and cyanobacteria are useful for humans.

These groups of organisms play a huge role in human life. Some of them prevent the development of infectious diseases, others are used in drug production technologies, and still others provide a balance in ecological system planets.

The third type of microbes are Azotobacteria, their effect on environment hard to overestimate.

Characteristics of sour milk stick

The lactic acid microbes are rod-shaped and Gram-positive.

The habitat of various microbes of this group is milk, dairy products such as yogurt, kefir, they also multiply in fermented foods and are part of the microflora of the intestines, mouth and female vagina. If the microflora is disturbed, thrush and some dangerous diseases can develop. The most common species of these microorganisms are L. acidophilus, L. reuteri, L. Plantarum and some others.

This group of microorganisms is known for its ability to use lactose for life and produce lactic acid as a by-product.

This ability of bacteria is used in the production of products that require fermentation. With the help of this process, it is possible to produce such a product from milk as yogurt. In addition, fermented milk organisms can be used in the salting process. This is due to the fact that lactic acid can act as a preservative.

In humans, lactic acid bacteria are involved in the process of digestion, ensuring the breakdown of lactose.

The acidic environment that occurs during the life of these bacteria prevents the development of pathogenic microflora in the intestine.

For this reason, lactic acid bacteria are an important component of probiotic preparations and dietary supplements.

Reviews of people using such drugs and dietary supplements to restore the microflora of the gastrointestinal tract suggest that these medicines have a high degree efficiency.

Brief description of bifidobacteria and Escherichia coli

This variety of microorganisms belongs to the group of gram-positive. They are branched and rod-shaped.

The habitat of this type of microbes is the human gastrointestinal tract.

This type of microflora is capable of producing acetic acid in addition to lactic acid.

This compound inhibits the growth of pathogenic microflora. The production of these compounds contributes to the control of pH levels in the stomach and intestines.

Such a representative as the B. Longum bacterium ensures the destruction of indigestible plant polymers.

Microorganisms B. longum and B. Infantis in the course of their activity produce compounds that prevent the development of diarrhea, candidiasis and fungal infections in infants and children.

Due to the presence of these beneficial properties, this type of microbe is often included in the composition of tablets sold in pharmacies of probiotic medicines.

Bifidobacteria are used in the production of various lactic acid products, such as yogurt, ryazhenka, and some others. Being in the gastrointestinal tract, they act as purifiers of the intestinal environment from harmful microflora.

The composition of the microflora of the gastrointestinal tract also includes Escherichia coli. She takes an active part in the processes of digestion of food. In addition, they are involved in some processes that ensure the vital activity of the cells of the body.

Some varieties of the stick are capable of causing poisoning in case of excessive development. Diarrhea and kidney failure.

Brief description of streptomycetes, nodule bacteria and cyanobacteria

Streptomycetes in nature live in soil, water and the remains of decaying organic matter.

These microbes are Gram-positive and filamentous under the microscope.

Most streptomycetes play a crucial role in maintaining the ecological balance in nature. Due to the fact that these microbes have the ability to process decaying organic matter, it is considered as a biorestorative agent.

Some types of streptomycetes are used to make effective antibiotics and antifungal drugs.

Mycorrhiza live in the soil, they exist in the roots of plants, entering into symbiosis with the plant. The most common symbiont of mycorrhiza are plants of the legume family.

Their benefit lies in the ability to bind atmospheric nitrogen, converting it in compounds into a form that is easily absorbed by plants.

Plants are not able to assimilate atmospheric nitrogen, so they are entirely dependent on the activity of this type of microorganism.

Cyanobacteria live most often in water and on the surface of bare rocks.

This group of living organisms are known as blue-green algae. This type of living organisms play an important role in wildlife. They are responsible for the fixation of atmospheric nitrogen in the aquatic environment.

The presence of such abilities in these bacteria as calcification and decalcification make them essential component systems for maintaining ecological balance in nature.

Microorganisms harmful to humans

Pathogenic representatives of microflora are microbes capable of provoking the development of various ailments in the human body.

Some types of microbes can provoke the development of deadly diseases.

Very often, such diseases can be transmitted from an infected person to a healthy person. In addition, a large number of pathogenic microflora can spoil food.

Representatives of pathogenic microflora can be gram-positive, gram-negative and rod-shaped microbes.

The table below shows the most famous representatives microflora.

Name	Habitat	Harm to humans
Mycobacteria	Live in water and soil	Able to provoke the development of tuberculosis, leprosy and ulcers
tetanus bacillus	Lives on the surface of the skin in the soil layer and in the digestive tract	Provoke the development of tetanus, muscle spasms and the occurrence of respiratory failure
Plague wand	Able to live only in humans, rodents and mammals	Can cause the appearance bubonic plague, pneumonia and skin infections
Helicobacter pylori	Able to develop on the gastric mucosa	Provokes the development of gastritis, peptic ulcer, produce cytotoxins and ammonia
anthrax bacillus	Lives in the soil layer	Causes anthrax
botulism stick	Develops in foodstuffs and on the surface of contaminated utensils	Contributes to the development of severe poisoning

Pathogenic microflora can develop in the body for a long time and feed on useful substances, weakening its condition, which leads to the development of various infectious diseases.

The most dangerous bacteria for humans

One of the most dangerous and resistant bacteria is a bacterium called Staphylococcus aureus. In the ranking of dangerous bacteria, it can rightfully take a prize.

This microbe is capable of provoking the development of several infectious diseases in the body.

Some varieties of this microflora are resistant to the strongest antibiotics and antiseptics.

Varieties of Staphylococcus aureus are able to live:

• in the upper parts of the human respiratory system;
• on the surface of open wounds;
• In the channels of the urinary organs.

For a human body with a strong immune system, this microbe is not dangerous, but if the body is weakened, it can manifest itself in all its glory.

The bacteria called Salmonella typhi are very dangerous. They are able to provoke the appearance of such a terrible and deadly infection in the body as typhoid fever, in addition, they can develop acute infections intestines.

The specified pathological flora is dangerous for the human body in that they produce toxic compounds that are very dangerous to health.

Poisoning by these compounds of the body can provoke the appearance of serious and fatal diseases.

Most people consider different bacterial organisms solely as harmful particles that can provoke the development of various pathological conditions. Nevertheless, according to scientists, the world of these organisms is very diverse. There are frankly dangerous bacteria that pose a danger to our body, but there are also useful ones - those that ensure the normal functioning of our organs and systems. Let's try to understand a little about these concepts and consider certain types of such organisms. Let's talk about bacteria in nature, harmful and beneficial to humans.

Beneficial bacteria

Scientists say that bacteria became the very first inhabitants of our large planet, and it is thanks to them that there is life on Earth now. Over the course of many millions of years, these organisms gradually adapted to the constantly changing conditions of existence, they changed their appearance and habitat. Bacteria were able to adapt to the surrounding space and were able to develop new and unique life support methods, including multiple biochemical reactions - catalysis, photosynthesis, and even seemingly simple respiration. Now bacteria coexist with human organisms, and such cooperation is distinguished by some harmony, because such organisms can bring real benefits.

After a small person is born, bacteria immediately begin to penetrate into his body. They are introduced through the respiratory tract along with air, enter the body along with breast milk, etc. The whole body is saturated with various bacteria.

Their number cannot be accurately calculated, but some scientists boldly say that the number of such organisms is comparable to the number of all cells. The digestive tract alone is home to four hundred varieties of different living bacteria. It is believed that a certain variety of them can grow only in a specific place. So lactic acid bacteria are able to grow and multiply in the intestines, others feel optimal in the oral cavity, and some others live only on the skin.

For many years of coexistence, man and such particles were able to recreate the optimal conditions for cooperation for both groups, which can be characterized as a useful symbiosis. At the same time, bacteria and our body combine their capabilities, while each side remains in the black.

Bacteria are able to collect particles of various cells on their surface, which is why the immune system does not perceive them as hostile and does not attack. However, after organs and systems are exposed to harmful viruses, beneficial bacteria rise to the defense and simply block the path of pathogens. When existing in the digestive tract, such substances also bring tangible benefits. They are engaged in the processing of leftover food, while releasing a significant amount of heat. It, in turn, is transmitted to nearby organs, and is carried throughout the body.

Deficiency of beneficial bacteria in the body or a change in their number causes the development of various pathological conditions. This situation can develop against the background of taking antibiotics, which effectively destroy both harmful and beneficial bacteria. To correct the number of beneficial bacteria, special preparations - probiotics can be consumed.

harmful bacteria

However, it is worth remembering that not all bacteria are human friends. Among them, there are enough dangerous varieties that can only bring harm. Such organisms, after penetrating into our body, cause the development of a variety of bacterial ailments. These are various colds, some varieties of pneumonia, and in addition syphilis, tetanus and other diseases, even deadly ones. There are also diseases of this type, which are transmitted by airborne droplets. This is dangerous tuberculosis, whooping cough, etc.

A significant number of diseases provoked by harmful bacteria develop due to the consumption of insufficiently high-quality food, unwashed and unprocessed vegetables and fruits, raw water, and insufficiently fried meat. You can protect yourself from such diseases by observing the norms and rules of hygiene. Examples of such dangerous diseases are dysentery, typhoid fever, etc.

Manifestations of diseases that have developed as a result of an attack of bacteria are the result of the pathological influence of poisons that these organisms produce, or that are formed against the background of their destruction. The human body is able to get rid of them thanks to the natural defense, which is based on the process of phagocytosis of bacteria by white blood cells, as well as on the immune system, which synthesizes antibodies. The latter carry out a bunch of foreign proteins and carbohydrates, and then simply eliminate them from the bloodstream.

Also, harmful bacteria can be destroyed with the help of natural and synthetic medicines, the most famous of which is penicillin. All drugs of this type are antibiotics, they differ depending on the active ingredient and on the mode of action. Some of them are able to destroy the cell membranes of bacteria, while others suspend the processes of their vital activity.

So, in nature there are a lot of bacteria that can bring benefits and harm to humans. Fortunately, the current level of development of medicine makes it possible to cope with the majority of pathological organisms of this kind.