Bacteria and their names. What bacteria are beneficial to humans?

Bacteria are the smallest ancient microorganisms invisible to the naked eye. Only under a microscope can one examine their structure, appearance and interaction with each other. The first microorganisms had a primitive structure; they developed, mutated, created colonies, and adapted to a changing environment. exchange amino acids with each other, which are necessary for growth and development.

Types of bacteria

IN school textbooks biology posted images different types bacteria that differ in shape:

Cocci are spherical organisms that differ in relative position. Under a microscope, it is noticeable that streptococci form a chain of balls, diplococci live in pairs, and staphylococci live in randomly shaped clusters. A number of cocci cause various inflammatory processes when they enter the human body (gonococcus, staphylococcus, streptococcus). Not all cocci living in the human body are pathogenic. Conditionally pathogenic species take part in the formation of the body’s defenses against external influences and are safe if the balance of the flora is maintained.
Rod-shaped ones differ in shape, size and ability to form spores. Spore-forming species are called bacilli. The bacilli include: tetanus bacillus, anthrax. Spores are formations inside a microorganism. The spores are insensitive to chemical treatment, their resistance to external influences is the key to preserving the species. It is known that spores are destroyed at high temperatures (above 120ºC).

Shapes of rod-shaped microbes:

with pointed poles, like fusobacterium, which is part of the normal microflora of the upper respiratory tract;
with thickened poles resembling a club, like corynebacterium - the causative agent of diphtheria;
with rounded ends, such as those of E. coli, which are necessary for the digestion process;
with straight ends, like the anthrax bacillus.

Gram(+) and gram(-)

Danish microbiologist Hans Gram conducted an experiment more than 100 years ago, after which all bacteria began to be classified as gram-positive and gram-negative. Gram-positive organisms create a long-term stable connection, which increases when exposed to iodine. Gram-negative, on the contrary, are not susceptible to the dye, their shell is firmly protected.

Gram-negative microbes include chlamydia, rickettsia, and gram-positive microbes include staphylococci, streptococci, and corynebacteria.

Today in medicine the test for gram(+) and gram(-) bacteria is widely used. is one of the methods for studying mucous membranes to determine the composition of the microflora.

Aerobic and anaerobic

How do bacteria live

Biologists define bacteria as a separate kingdom; they are different from other living things. It is a single-celled organism without a nucleus inside. Their shape can be in the form of a ball, cone, stick, or spiral. Prokaryotes use flagella to move.

Biofilm is a city for microorganisms and goes through several stages of formation:

Adhesion or sorption is the attachment of a microorganism to a surface. As a rule, films are formed at the interface of two media: liquid and air, liquid and liquid. The initial stage is reversible and film formation can be prevented.
Fixation - bacteria release polymers, ensuring their strong fixation, forming a matrix for strength and protection.
Maturation - microbes merge and exchange nutrients, microcolonies develop.
Growth stage - bacteria accumulate, merge, and are displaced. The number of microorganisms ranges from 5 to 35%, the rest of the space is occupied by the intercellular matrix.
Dispersion - microorganisms periodically detach from the film, attach to other surfaces and form a biofilm.

The processes that occur in a biofilm are different from what happens to a microbe that is not integral part colonies. Colonies are stable, microbes organize unified system behavioral reactions, determining the interaction of members inside the matrix and outside the film. Human mucous membranes are populated big amount microorganisms that produce a gel for protection and ensure the stability of organ functioning. An example is the gastric mucosa. It is known that Helicobacter pylori, which is considered the cause of gastric ulcers, is present in more than 80% of examined people, but at the same time peptic ulcer Not everyone develops it. It is assumed that Helicobacter pylori, being members of the colony, is involved in digestion. Their ability to cause harm manifests itself only after certain conditions are created.

The interaction of bacteria in biofilms is still poorly understood. But today, some microbes have become human assistants when carrying out restoration work and increasing the strength of coatings. In Europe, manufacturers of disinfectants offer to treat surfaces with bacterial solutions containing safe microorganisms that prevent the development of pathogenic flora. Bacteria are used to create polymer compounds and will also eventually generate electricity.

Rice. 1. Human body 90% consists of microbial cells. It contains from 500 to 1000 different types of bacteria or trillions of these amazing residents, which amounts to up to 4 kg of total weight.

Rice. 2. Bacteria inhabiting the oral cavity: Streptococcus mutants ( green color). Bakteroides gingivalis, causes periodontitis ( purple colour). Candida albicus ( yellow). Causes candidiasis of the skin and internal organs.

Rice. 7. Mycobacterium tuberculosis. Bacteria have been causing diseases in humans and animals for many millennia. The tuberculosis bacillus is extremely resistant to external environment. In 95% of cases it is transmitted by airborne droplets. Most often affects the lungs.

Rice. 8. The causative agent of diphtheria is corynebacteria or Leffler's bacillus. It most often develops in the epithelium of the mucous layer of the tonsils, less often in the larynx. Swelling of the larynx and enlarged lymph nodes can lead to asphyxia. The pathogen's toxin is fixed on the membranes of the cells of the heart muscle, kidneys, adrenal glands and nerve ganglia and destroys them.

Rice. 9. Causative agents of staphylococcal infection. Pathogenic staphylococci cause extensive damage to the skin and its appendages, damage to many internal organs, foodborne toxic infection, enteritis and colitis, sepsis and toxic shock.

Rice. 10. Meningococci are the causative agents of meningococcal infection. Up to 80% of cases are children. The infection is transmitted by airborne droplets from sick and healthy carriers of bacteria.

Rice. 11. Bordetella pertussis.

Rice. 12. The causative agent of scarlet fever is streptococcus pyogenes.

Harmful bacteria of water microflora

Water is the habitat for many microbes. In 1 cm3 of water you can count up to 1 million microbial bodies. Pathogenic microorganisms enter water from industrial enterprises, settlements and livestock farms. Water containing pathogenic microbes can become a source dysentery, cholera, typhoid fever, tularemia, leptospirosis, etc. Vibrio cholerae and can remain in water for quite a long time.

Rice. 13. Shigella. Pathogens cause bacillary dysentery. Shigella destroys the epithelium of the colon mucosa, causing severe ulcerative colitis. Their toxins affect the myocardium, nervous and vascular systems.

Rice. 14. . Vibrios do not destroy the cells of the mucous layer of the small intestine, but are located on their surface. They secrete a toxin called choleragen, the action of which leads to disruption of water-salt metabolism, causing the body to lose up to 30 liters of fluid per day.

Rice. 15. Salmonella is the causative agent of typhoid fever and paratyphoid fever. Affects epithelium and lymphoid elements small intestine. With the bloodstream they enter the bone marrow, spleen and gall bladder, from which the pathogens again enter the small intestine. As a result of immune inflammation, the wall of the small intestine ruptures and peritonitis occurs.

Rice. 16. Causative agents of tularemia (coccobacteria blue color). They affect the respiratory tract and intestines. They have the ability to penetrate the human body through intact skin and mucous membranes of the eyes, nasopharynx, larynx and intestines. The peculiarity of the disease is damage to the lymph nodes (primary bubo).

Rice. 17. Leptospira. They affect the human capillary network, often the liver, kidneys and muscles. The disease is called infectious jaundice.

Harmful bacteria of soil microflora

Billions of “bad” bacteria live in the soil. In a 30-centimeter thickness of 1 hectare of land there are up to 30 tons of bacteria. Possessing a powerful set of enzymes, they are engaged in the breakdown of proteins into amino acids, thereby taking an active part in the processes of decay. However, these bacteria bring a lot of trouble to humans. Thanks to the activity of these microbes, food spoils very quickly. Man has learned to protect shelf-stable foods by sterilizing, salting, smoking and freezing. Some types of these bacteria can spoil even salted and frozen foods. enter the soil from sick animals and humans. Some types of bacteria and fungi stay in the soil for decades. This is facilitated by the ability of these microorganisms to form spores, which long years protect them from unfavorable conditions external environment. They cause the most dangerous diseases - anthrax, botulism, and tetanus.

Rice. 18. The causative agent of anthrax. It remains in the soil in a spore-like state for decades. A particularly dangerous disease. Its second name is malignant carbuncle. The prognosis of the disease is unfavorable.

Rice. 19. The causative agent of botulism produces a powerful toxin. 1 microgram of this poison kills a person. Botulinum toxin affects the nervous system, oculomotor nerves, up to paralysis and cranial nerves. The mortality rate from botulism reaches 60%.

Rice. 20. The causative agents of gas gangrene multiply very quickly in soft tissues the body without access to air, causing severe damage. Preserves in a spore-like state in the external environment long time.

Rice. 21. Putrefactive bacteria.

Rice. 22. Damage to food products by putrefactive bacteria.

Harmful bacteria that damage wood

A number of bacteria and fungi intensively decompose fiber, playing an important sanitary role. However, among them there are bacteria that cause serious diseases in animals. Molds destroy wood. Wood staining mushrooms paint wood in different colors. House mushroom leads the wood to a rotten state. As a result of the vital activity of this fungus, wooden buildings are destroyed. Great damage The activity of these fungi causes the destruction of livestock buildings.

Rice. 23. The photo shows how the house fungus destroyed the wooden floor beams.

Rice. 24. Spoiled appearance logs (blue staining) affected by wood staining fungus.

Rice. 25. House mushroom Merulius Lacrimans. a – cotton wool mycelium; b – young fruiting body; c – old fruiting body; d – old mycelium, cords and wood rot.

Harmful bacteria in food

Products contaminated with dangerous bacteria become a source of intestinal diseases: typhoid fever, salmonellosis, cholera, dysentery etc. Toxins that are released staphylococci and botulism bacilli, cause toxic infections. Cheeses and all dairy products may be affected butyric acid bacteria, which cause butyric acid fermentation, resulting in products having an unpleasant odor and color. Vinegar sticks cause acetic fermentation, which leads to sour wine and beer. Bacteria and micrococci that cause rotting contain proteolytic enzymes that break down proteins, which gives products a foul-smelling odor and bitter taste. Products become covered in mold as a result of damage to mold fungi.

Rice. 26. Bread affected by mold.

Rice. 27. Cheese affected by mold and putrefactive bacteria.

Rice. 28. “Wild yeast” Pichia pastoris. The photo was taken with 600x magnification. The worst pest of beer. Found everywhere in nature.

Harmful bacteria that decompose dietary fats

Butyric acid microbes are everywhere. 25 of their species cause butyric acid fermentation. Life activity fat-digesting bacteria leads to rancidity of the oil. Under their influence, soybean and sunflower seeds become rancid. Butyric acid fermentation, which is caused by these microbes, spoils the silage, and it is poorly eaten by livestock. And wet grain and hay, infected with butyric acid microbes, self-heats. The moisture contained in butter is a good environment for reproduction. putrefactive bacteria and yeast fungi. Because of this, the oil deteriorates not only outside, but also inside. If the oil is stored for a long time, then it can settle on its surface. molds.

Rice. 29. Caviar oil affected by fat-splitting bacteria.

Harmful bacteria affecting eggs and egg products

Bacteria and fungi penetrate into eggs through the pores of the outer shell and its damage. Most often, eggs are infected with salmonella bacteria and molds, egg powder - salmonella and .

Rice. 30. Spoiled eggs.

Harmful bacteria in canned food

for humans are toxins botulinum bacillus and perfringens bacillus. Their spores exhibit high heat resistance, which allows microbes to remain viable after pasteurization of canned food. Being inside the jar, without access to oxygen, they begin to multiply. This releases carbon dioxide and hydrogen, which causes the jar to swell. Eating such a product causes severe food toxicosis, which is characterized by an extremely severe course and often ends in the death of the patient. Canned meat and vegetables are amazing acetic acid bacteria, As a result, the contents of the canned food sour. Development does not cause bloating of canned food, since staphylococcus does not produce gases.

Rice. 31. Canned meat affected by acetic acid bacteria, as a result of which the contents of the cans turn sour.

Rice. 32. Swollen canned food may contain botulinum bacilli and perfringens bacilli. The jar is inflated by carbon dioxide, which is released by bacteria during reproduction.

Harmful bacteria in grain products and bread

Ergot and other molds that infect grains are the most dangerous for humans. The toxins of these mushrooms are heat stable and are not destroyed by baking. Toxicoses caused by the use of such products are severe. Torment, stricken lactic acid bacteria, has an unpleasant taste and specific smell, lumpy in appearance. Already baked bread is affected Bacillus subtilis(Bac. subtilis) or “gravid disease”. The bacilli secrete enzymes that break down bread starch, which is manifested, first, by an odor not characteristic of bread, and then by the stickiness and viscousness of the bread crumb. Green, white and capitate mold affects already baked bread. It spreads through the air.

Rice. 33. In the photo there is purple ergot. Low doses of ergot cause severe pain, mental disorders and aggressive behavior. High doses of ergot cause painful death. Its action is associated with muscle contraction under the influence of fungal alkaloids.

Rice. 34. Mold mycelium.

Rice. 35. Spores of green, white and capitate molds can fall from the air onto already baked bread and infect it.

Harmful bacteria that affect fruits, vegetables and berries

Fruits, vegetables and berries are seeded soil bacteria, mold fungi and yeast, which cause intestinal infections. The mycotoxin patulin, which is secreted mushrooms of the genus Penicillium, capable of causing cancer in humans. Yersinia enterocolitica causes the disease yersiniosis or pseudotuberculosis, which affects the skin, gastrointestinal tract and other organs and systems.

Rice. 36. Damage to berries by mold fungi.

Rice. 37. Skin lesions due to yersiniosis.

Harmful bacteria penetrate into the human body with food, through the air, wounds and mucous membranes. The severity of diseases caused by pathogenic microbes depends on the poisons they produce and the toxins produced by them. mass death. Over the course of thousands of years, they have acquired many adaptations that allow them to penetrate and remain in the tissues of a living organism and resist immunity.

Explore bad influence microorganisms on the body and develop preventive actions- this is the task of man!

Articles in the section "What do we know about microbes"Most popular

The human body is home to many types of bacteria, including beneficial, pathogenic and opportunistic forms. Let's consider the features of the development of microbes, the diseases they provoke and methods of infection by pathogens.

There is an opinion that the number of bacteria in the human body exceeds the volume of its own cells by 10 times. However latest research questioned this indicator. According to new materials, it varies in the range from 1.5 to 2. In total, there are about 10 thousand species of bacteria that have adapted to living in various conditions.

They enter the human body from the environment, where they can persist for a long time. Pathogenic forms are causative agents of diseases manifested by varying degrees intensity and danger. This can range from a mild skin rash to a serious infectious manifestation that poses a threat to the patient’s life.

Bacteria appeared on Earth approximately 3.5 billion years ago. Their structure differs slightly from modern species. All bacteria are prokaryotes, which means that their cells do not have a formed nucleus. Outside they are surrounded cell wall, which preserves the shape of the microorganism. Some species are capable of producing mucus, which is similar to a capsule and protects the microbe from drying out. There are forms that can actively move using special flagella.

The internal structure of bacteria is quite simple. The cell contains the main inclusions:

cytoplasm, which is 75% water, and the remaining 25% is minerals;
granules, which are a source of energy for the body;
mesosomes necessary for cell division and sporulation;
nucleoid containing genetic information and acting as a core;
ribosomes involved in protein synthesis;
plasmids.

The shape of bacterial cells can be spherical, rod-shaped, convoluted or club-shaped. They can be located singly or in groups. In this case, diplococci (in pairs), streptococci (in the form of chains), staphylococci (in the form of grapevine) and sartsina (placement in a package). Some rod-shaped bacteria form spores when exposed to unfavorable conditions. These types are called bacilli.

All microorganisms reproduce by dividing cells in two. Moreover, the rate of population increase can be as little as 20 minutes. Such a high reproduction rate is observed on food products and other nutrient substrates.

Beneficial bacteria that live in the human body

The main representatives of beneficial microflora include:

Bifidobacteria. They live mainly in the large intestine, where they participate in the activation of parietal digestion. In the process of life, they form a natural biological barrier that prevents the penetration of pathogens and toxins. In addition, they produce special acids, suppressing the reproduction of pathogenic and opportunistic forms. Without the participation of bifidobacteria, the synthesis of vitamins B and K, as well as the absorption of iron and calcium, does not occur.
Lactobacilli during their life processes form lactase, which breaks down milk sugar. Due to the production of lactic acid, they maintain the necessary level of acidity in the intestines, and also accelerate the healing of affected areas of the gastrointestinal tract. By analogy with bifidobacteria, they stimulate the immune system by activating the process of phagocytosis.

These microbes guard the digestive tract, protecting it from useless microorganisms that can settle in the stomach and worsen a person’s condition.

Normal human microflora must contain both types of microorganisms. Moreover, the number of bifidobacteria can be up to 95% of the entire biocenosis of the body, and lactobacilli - only 5%. Moreover, the latter live mainly in the vagina and oral cavity.

Bifidobacteria and lactobacilli are included in preparations used to normalize human microflora. They are called probiotics, and in addition to these microorganisms they contain propionic acid species, thermophilic streptococci and lactococci. Combined medications are often prescribed for dysbiosis, antibiotic treatment, as well as any helminthic infestations.

To maintain optimal levels beneficial bacteria you need to eat certain foods. They must consist of components that are not digested in upper sections intestines, thereby stimulating the proliferation of beneficial microbes. Such products include raw vegetables, dairy products, bran, cereals, berries, dried fruits.

Pathogenic forms of corynebacteria

Microorganisms of the genus Corynebacterium belong to gram-positive bacteria with a rod-shaped body shape. Most representatives live in nature and do not pose a threat to human health. However, several species are pathogens serious illnesses requiring hospital treatment.

Corynebacterium diphtheriae are slightly curved rods with a thickening on one side of the cell. Their size ranges from 0.1 to 8 microns. As the name suggests, the bacterium is the cause of diphtheria. Symptoms of the disease depend on the location of the pathogen. This may be the oral cavity, nose, larynx, trachea, bronchi, genitals, skin. Poisoning of the human body occurs due to the release of a special substance called exotoxin by bacteria. Its accumulation leads to increased temperature, fever, headache, nausea, discomfort in the throat, and enlarged lymph nodes.

Another species, Corynebacterium minutissimum, provokes the development of dermatological diseases. One of them is erythrasma, which occurs only in adults. It appears in the form of rashes on the surface of the skin folds: inguinal-scrotal, between the buttocks, sometimes in the interdigital areas. The lesions look like brown spots of a non-inflamed structure, which can cause mild itching. The bacterium survives well on household items, including phones and tablets.

Corynebacteria are also part of the normal microflora of the human large intestine. Non-pathogenic forms are actively used in industry for the production of amino acids, enzymes, and cheeses. Corynebacterium glutamicum is used in the production of glutamic acid, which is known as food additives E620.

Streptomycetes, their significance for humans

The genus Streptomyces includes spore-forming species that live primarily in soil. They form chains of cells and resemble the shape of mushroom mycelium. In the process of life, they release special volatile substances that give the earth a characteristic damp smell. A necessary condition The existence of streptomycetes is the presence of molecular oxygen.

Many species are capable of producing valuable medicinal substances belonging to the group of antibiotics (streptomycin, erythromycin). In more early periods Streptomycetes have been used to produce:

Physostigmine, used as a pain reliever for increased eye pressure;
Tacrolimus, necessary for prophylaxis during kidney, liver and bone marrow transplants;
Allosamidine, which is active against insects and fungi.

Streptomyces bikiniensis is a pathogenic form that provokes the development of bacteremia. With this disease, bacteria enter the bloodstream and can spread throughout the body.

Helicobacter pylori as a harmful bacterium

Helicobacter pylori has a spiral-shaped cell measuring up to 3 microns. It is able to actively move even in thick mucus with the help of flagella. The bacterium infects various parts of the stomach and duodenum, causing the disease helicobacteriosis. The cause of ulcers and gastritis is very often this type microbe

Helicobacter attaches to the surface of the gastric mucosa, damaging it and provoking the development of an inflammatory process. Infection with the bacterium manifests itself in the form of repeated severe pain in the stomach, which subsides after eating. Heartburn, nausea, vomiting, poor digestibility of meat dishes are also symptoms of the disease.

There is an opinion that Helicobacter pylori is part of the normal human microflora, and a pathological condition occurs when its number increases. At the same time, about 50 strains of this bacterium live in the human stomach, only 5 of which pose a health hazard. If antibiotics are prescribed, all microorganisms are destroyed, including harmless ones.

Escherichia coli as a representative of the natural human microflora

Escherichia coli is a rod-shaped bacteria that plays important role in the functioning of the gastrointestinal tract. They can exist for a long time in environment, including soil, water and feces. Microorganisms quickly die when boiled and exposed to chlorine solutions. Bacteria actively multiply on food products, especially in milk.

Escherichia coli is able to absorb oxygen from the intestinal lumen, thereby protecting beneficial lacto- and bifidobacteria from destruction. In addition, it is involved in the production of B vitamins, fatty acids, and also affects the absorption of iron and calcium by the intestines. Normally, the bacterial content in human feces should be no more than 108 CFU/g. Excess this indicator indicates the development of dysbiosis against the background of an inflammatory process in the body.

Pathogenic forms can cause infectious diseases gastrointestinal tract accompanied by intoxication and fever. Enteropathogenic strains of Escherichia coli develop in the small intestine of newborns and cause severe diarrhea. In women, if intimate hygiene is not observed, bacteria can enter the genitourinary organs, provoking the development of bacteriuria.

Dangerous bacterium Staphylococcus aureus

Staphylococcus aureus belongs to the non-motile spherical microbes of the genus Staphylococcus. Cells can be arranged singly, in pairs or in clusters. Due to the content of pigments of the carotenoid group, the bacterium has a golden color, which is noticeable when examined under a microscope. Staphylococcus aureus is characterized by increased tolerance to high temperatures, light and chemicals.

The microorganism is the cause of the appearance of purulent-inflammatory foci of infection in humans. The main areas of localization of the pathogen include the nasal passages and axillary areas. However, cases of damage to the larynx and gastrointestinal tract are not uncommon. The bacterium is widespread in medical institutions. About 30% of patients after hospitalization are carriers of Staphylococcus aureus.

The main symptoms of infection with a pathogen include fever, lethargy, nausea, and lack of appetite. When the skin is damaged, small blisters form, resembling burns, which over time turn into open wounds. Rhinitis, sore throat, pharyngitis, pneumonia can develop when the pathogen spreads in the respiratory tract. Frequent and painful urination and lower back pain indicate the localization of staphylococcus in the urethra.

Pseudomonas aeruginosa as one of the pathogenic species of bacteria

The bacterium is a motile flagellar microorganism; its main habitat is soil and water. During its life, it colors the food environment blue-green, which is where its name comes from. It is highly resistant to antibiotics.

Pseudomonas aeruginosa is dangerous for people with reduced immunity and, as a rule, is a nosocomial infection. Infection is possible through household items, towels, untreated medical instruments. Increased accumulation of the microorganism is observed on the wound surface and in the depths of purulent areas of the skin.

Pseudomonas aeruginosa infection can develop in:

ENT organs and accompanied by otitis, sinusitis;
urinary tract with the appearance of urethritis, cystitis;
soft tissues;
intestines, causing dysbiosis, enteritis, colitis.

Bacteria, along with viruses, are the causative agents of numerous diseases that are not always treatable. The diversity of species and their rapid adaptation to the effects of drugs make microbes a serious threat to human health. However, in most cases, infection can be avoided by following good personal hygiene and strengthening the immune system.

Where do bacteria settle in the human body?

Most of them inhabit the intestines, providing harmonious microflora.
They live on mucous membranes, including oral cavity.
Many microorganisms inhabit the skin.

What microorganisms are responsible for:

They support immune function. If there is a lack of beneficial microbes, the body is immediately attacked by harmful ones.
By feeding on the components of plant foods, bacteria help digestion. The bulk of products that reach the large intestine are digested precisely thanks to bacteria.
Benefits of intestinal microorganisms - in the synthesis of B vitamins, antibodies, absorption of fatty acids.
Microbiota maintains water-salt balance.
Bacteria on the skin protect the integument from penetration of harmful microorganisms. The same applies to the population of mucous membranes.

What happens if you remove bacteria from the human body? Vitamins will not be absorbed, hemoglobin in the blood will drop, diseases of the skin, gastrointestinal tract, respiratory system, etc. will begin to progress. Conclusion: the main function of bacteria in the human body is protective. Let's take a closer look at what types of microorganisms exist and how to support their work.

Main groups of beneficial bacteria

Beneficial bacteria for humans can be divided into 4 main groups:

bifidobacteria;
lactobacilli;
enterococci;
coli.

The most common type of beneficial microbiota. The task is to create an acidic environment in the intestines. In such conditions, pathogenic microflora cannot survive. The bacteria produce lactic acid and acetate. Thus, the intestinal tract is not afraid of the processes of fermentation and decay.

Another property of bifidobacteria is antitumor. Microorganisms participate in the synthesis of vitamin C, the main antioxidant in the body. Vitamins D and B-group are absorbed thanks to this type of microbes. The digestion of carbohydrates is also accelerated. Bifidobacteria increase the ability of the intestinal walls to absorb valuable substances, including calcium, magnesium and iron ions.

From the mouth to the colon, lactobacilli live in the digestive tract. Joint action These bacteria and other microorganisms control the proliferation of pathogenic microflora. Causative agents of intestinal infections are much less likely to infect the system if lactobacilli inhabit it in sufficient quantities.

The task of the little hard workers is to normalize the functioning of the intestinal tract and support immune function. Microbiota is used in the food and medical industries: from healthy kefirs to drugs for normalizing intestinal microflora.

Lactobacilli are especially valuable for women's health: the acidic environment of the mucous membranes of the reproductive system does not allow the development of bacterial vaginosis.

Advice! Biologists say that the immune system starts in the intestines. The body’s ability to resist harmful bacteria depends on the condition of the tract. Maintain a normal gastrointestinal tract, and then not only will the absorption of food improve, but the body’s defenses will also increase.

Enterococci

The habitat of enterococci is the small intestine. They block the proliferation of pathogenic microorganisms and help absorb sucrose.

The magazine "Polzateevo" found out that there is an intermediate group of bacteria - conditionally pathogenic. In one state they are beneficial, but when any conditions change they become harmful. These include enterococci. Staphylococci that live on the skin also have a dual effect: they protect the skin from harmful microbes, but they themselves can get into the wound and cause a pathological process.

E. coli often causes negative associations, but only some species from this group cause harm. Most E. coli have a beneficial effect on the tract.

These microorganisms synthesize a number of B vitamins: folic and nicotinic acid, thiamine, riboflavin. The indirect effect of such synthesis is the improvement of blood composition.

Which bacteria are harmful?

Harmful bacteria are more widely known than beneficial bacteria, as they pose a direct threat. Many people know the dangers of salmonella, plague bacillus and vibrio cholerae.

The most dangerous bacteria for humans:

Tetanus bacillus: lives on the skin and can cause tetanus, muscle spasms and respiratory problems.
Botulism stick. If you eat a spoiled product with this pathogenic microorganism, you can get fatal poisoning. Botulism often develops in expired sausages and fish.
Staphylococcus aureus is capable of causing several ailments in the body at once, is resistant to many antibiotics and incredibly quickly adapts to drugs, becoming insensitive to them.
Salmonella is the cause of acute intestinal infections, including a very dangerous disease - typhoid fever.

Prevention of dysbacteriosis

Living in an urban environment with bad environment and nutrition significantly increases the risk of dysbiosis - an imbalance of bacteria in the human body. Most often, the intestines suffer from dysbacteriosis, less often - the mucous membranes. Signs of a lack of beneficial bacteria: gas formation, bloating, abdominal pain, upset stool. If the disease is neglected, vitamin deficiency, anemia, unpleasant odor of the mucous membranes of the reproductive system, weight loss, and skin defects may develop.

Dysbacteriosis easily develops even when taking antibiotic drugs. To restore the microbiota, probiotics are prescribed - compositions with living organisms and prebiotics - preparations with substances that stimulate their development. Fermented milk drinks containing live bifidobacteria and lactobacilli are also considered beneficial.

In addition to therapy, beneficial microbiota responds well to fasting days, eating fresh fruits and vegetables, whole grains.

The role of bacteria in nature

The kingdom of bacteria is one of the most numerous on the planet. These microscopic creatures bring benefits and harm not only to humans, but also to all other species, and provide many processes in nature. Bacteria are found in the air and soil. Azotobacter is a very useful soil inhabitant that synthesizes nitrogen from the air, converting it into ammonium ions. In this form, the element is easily absorbed by plants. These same microorganisms cleanse soils of heavy metals and fill them with biologically active substances.

Don't be afraid of bacteria: our body is designed in such a way that it cannot function normally without these tiny workers. If their number is normal, then the immune, digestive and a number of other functions of the body will be fine.

They surround us everywhere. Many of them are very necessary and useful for humans, but many, on the contrary, cause terrible diseases.
Do you know what forms bacteria come in? How do they reproduce? What do they eat? Do you want to know?
.site) will help you find in this article.

Shapes and sizes of bacteria

Most bacteria are single-celled organisms. They come in a wide variety of shapes. Bacteria are given names depending on their shape. For example, round-shaped bacteria are called cocci (well-known streptococci and staphylococci), rod-shaped bacteria are called bacilli, pseudomonads or clostridia (bacteria of this shape include the famous tuberculosis bacillus or Koch's wand). Can bacteria have the shape of spirals, then their names spirochetes, vibrils or spirilla. Not so often, but bacteria in the shape of stars, various polygons or other geometric shapes do occur.

Bacteria are not at all large, their sizes range from half to five micrometers. The most large bacterium has a size of seven hundred and fifty micrometers. After the discovery of nanobacteria, it turned out that their size is much smaller than scientists previously imagined. However, to date, nanobacteria have not been well studied. Some scientists even doubt their existence.

Aggregates and multicellular organisms

Bacteria can attach to each other using mucus, forming cellular aggregates. Moreover, each individual bacterium is a self-sufficient organism, the vital activity of which does not depend in any way on its relatives glued to it. Sometimes it happens that bacteria adhere in order to carry out some kind of general function. Some bacteria, usually filamentous, can also form multicellular organisms.

How do they move?

There are bacteria that are not able to move on their own, but there are also those that are equipped with special devices for movement. Some bacteria move using flagella, while others can glide. How bacteria glide is not yet fully understood. It is believed that bacteria secrete a special mucus that makes sliding easier. There are also bacteria that can “dive”. In order to descend into the depths of any liquid medium, such a microorganism can change its density. In order for a bacterium to move in any direction, it must receive irritation.

Nutrition

There are bacteria that can only feed organic compounds, and there are those that can process inorganics into organics and after that use them for their own needs. Bacteria obtain energy in three ways: using respiration, fermentation or photosynthesis.

Reproduction

Regarding the proliferation of bacteria, we can say that it is also not uniform. There are bacteria that do not divide into sexes and multiply simple division or budding. Some cyanobacteria have the ability to multiple divisions, that is, in one go they can produce up to a thousand “newborn” bacteria. There are also bacteria that reproduce sexually. Of course, they do all this very primitively. But at the same time, two bacteria transfer their genetic data to the new cell - this is the main feature of sexual reproduction.

Bacteria undoubtedly deserve your attention not only because they cause many diseases. These microorganisms were the first living beings to inhabit our planet. The history of bacteria on Earth goes back almost four billion years! The most ancient cyanobacteria existing today are cyanobacteria; they appeared three and a half billion years ago.

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