Pathogenic bacteria are human parasites. Where live? What diseases cause? What are bacteria: names and types Action of bacteria

Bacteria- one of the most ancient organisms on Earth. Despite the simplicity of their structure, they live in all possible habitats. Most of them are found in the soil (up to several billion bacterial cells per 1 gram of soil). There are many bacteria in the air, water, food, inside and on the bodies of living organisms. Bacteria have been found in places where other organisms cannot live (on glaciers, in volcanoes).

Typically a bacterium is a single cell (although there are colonial forms). Moreover, this cell is very small (from fractions of a micron to several tens of microns). But the main feature of a bacterial cell is the absence of a cell nucleus. In other words, bacteria belong prokaryotes.

Bacteria are either mobile or immobile. In the case of non-motile forms, movement is carried out using flagella. There may be several of them, or there may be only one.

Cells of different types of bacteria can differ greatly in shape. There are spherical bacteria ( cocci), rod-shaped ( bacilli), similar to a comma ( vibrios), crimped ( spirochetes, spirilla) and etc.

Structure of a bacterial cell

Many bacterial cells have mucous capsule. It performs a protective function. In particular, it protects the cell from drying out.

Like plant cells, bacterial cells have cell wall. However, unlike plants, its structure and chemical composition somewhat different. The cell wall is made up of layers of complex carbohydrates. Its structure is such that it allows various substances to penetrate into the cell.

Under the cell wall is cytoplasmic membranenA.

Bacteria are classified as prokaryotes because their cells do not have a formed nucleus. They do not have the chromosomes characteristic of eukaryotic cells. The chromosome contains not only DNA, but also protein. In bacteria, their chromosome consists only of DNA and is a circular molecule. This genetic apparatus of bacteria is called nucleoid. The nucleoid is located directly in the cytoplasm, usually in the center of the cell.

Bacteria do not have true mitochondria and a number of other cellular organelles (Golgi complex, endoplasmic reticulum). Their functions are performed by invaginations of the cell cytoplasmic membrane. Such invaginations are called mesosomes.

In the cytoplasm there is ribosomes, as well as various organic inclusion: proteins, carbohydrates (glycogen), fats. Bacterial cells may also contain various pigments. Depending on the presence or absence of certain pigments, bacteria can be colorless, green, or purple.

Nutrition of bacteria

Bacteria arose at the dawn of life on Earth. They were the ones who “discovered” different ways of eating. Only later, with the complication of organisms, two large kingdoms clearly emerged: Plants and Animals. They differ from each other primarily in the way they feed. Plants are autotrophs, and animals are heterotrophs. Bacteria have both types of nutrition.

Nutrition is the way a cell or body obtains the necessary organic substances. They can be obtained from outside or synthesized independently from inorganic substances.

Autotrophic bacteria

Autotrophic bacteria synthesize organic substances from inorganic ones. The synthesis process requires energy. Depending on where autotrophic bacteria receive this energy from, they are divided into photosynthetic and chemosynthetic.

Photosynthetic bacteria use the energy of the Sun, capturing its radiation. In this they are similar to plants. However, while plants release oxygen during photosynthesis, most photosynthetic bacteria do not release it. That is, bacterial photosynthesis is anaerobic. Also, the green pigment of bacteria differs from the similar pigment of plants and is called bacteriochlorophyll. Bacteria do not have chloroplasts. Mostly photosynthetic bacteria live in bodies of water (fresh and salty).

Chemosynthetic bacteria For the synthesis of organic substances from inorganic ones, the energy of various chemical reactions. Energy is not released in all reactions, but only in exothermic ones. Some of these reactions take place in bacterial cells. So in nitrifying bacteria the oxidation of ammonia into nitrites and nitrates occurs. Iron bacteria oxidize ferrous iron into oxide iron. Hydrogen bacteria oxidize hydrogen molecules.

Heterotrophic bacteria

Heterotrophic bacteria are not capable of synthesizing organic substances from inorganic ones. Therefore, we are forced to obtain them from the environment.

Bacteria that feed on the organic remains of other organisms (including dead bodies) are called saprophytic bacteria. They are otherwise called rotting bacteria. There are many such bacteria in the soil, where they decompose humus into inorganic substances, which are subsequently used by plants. Lactic acid bacteria feed on sugars, converting them into lactic acid. Butyric acid bacteria decompose organic acids, carbohydrates, alcohols to butyric acid.

Nodule bacteria live in the roots of plants and feed on the organic matter of the living plant. However, they fix nitrogen from the air and provide it to the plant. That is, in this case there is a symbiosis. Other heterotrophic symbiont bacteria live in the digestive system of animals, helping to digest food.

During the process of respiration, organic substances are destroyed and energy is released. This energy is subsequently spent on various vital processes (for example, movement).

Effective way obtaining energy is oxygen respiration. However, some bacteria can obtain energy without oxygen. Thus, there are aerobic and anaerobic bacteria.

Aerobic bacteria oxygen is needed, so they live in places where it is available. Oxygen participates in the oxidation reaction of organic substances to carbon dioxide and water. In the process of such respiration, bacteria receive a relatively large amount of energy. This method of breathing is characteristic of the vast majority of organisms.

Anaerobic bacteria They do not need oxygen to breathe, so they can live in an oxygen-free environment. They receive energy from fermentation reactions. This oxidation method is ineffective.

Bacteria reproduction

In most cases, bacteria reproduce by dividing their cells in two. Before this, the circular DNA molecule doubles. Each daughter cell receives one of these molecules and is therefore a genetic copy of the mother cell (clone). Thus, it is typical for bacteria asexual reproduction.

Under favorable conditions (with sufficient nutrients and favorable environmental conditions), bacterial cells divide very quickly. So from one bacterium hundreds of millions of cells can form per day.

Although bacteria reproduce asexually, in some cases they exhibit the so-called sexual process, which flows in the form conjugation. During conjugation, two different bacterial cells come closer and a connection is established between their cytoplasms. Parts of the DNA of one cell are transferred to the second, and parts of the DNA of the second cell are transferred to the first. Thus, during the sexual process, bacteria exchange genetic information. Sometimes bacteria exchange not sections of DNA, but entire DNA molecules.

Bacterial spores

The vast majority of bacteria form spores under unfavorable conditions. Bacterial spores are mainly a way of surviving unfavorable conditions and a method of dispersal, rather than a method of reproduction.

When a spore is formed, the cytoplasm of the bacterial cell contracts, and the cell itself is covered with a dense, thick protective membrane.

Bacterial spores remain viable for a long time and can survive very unfavourable conditions(extremely high and low temperatures, drying out).

When a spore finds itself in favorable conditions, it swells. After this, the protective shell is shed, and an ordinary bacterial cell appears. It happens that cell division occurs and several bacteria are formed. That is, sporulation is combined with reproduction.

The importance of bacteria

The role of bacteria in the cycle of substances in nature is enormous. This primarily applies to rotting bacteria (saprophytes). They are called nature's orderlies. By decomposing the remains of plants and animals, bacteria convert complex organic substances into simple inorganic substances (carbon dioxide, water, ammonia, hydrogen sulfide).

Bacteria increase soil fertility by enriching it with nitrogen. Nitrifying bacteria undergo reactions during which nitrites are formed from ammonia, and nitrates from nitrites. Nodule bacteria are able to assimilate atmospheric nitrogen, synthesizing nitrogen compounds. They live in the roots of plants, forming nodules. Thanks to these bacteria, plants receive the nitrogen compounds they need. Basically, leguminous plants enter into symbiosis with nodule bacteria. After they die, the soil is enriched with nitrogen. This is often used in agriculture.

In the stomach of ruminants, bacteria break down cellulose, which promotes more efficient digestion.

The great positive role of bacteria in Food Industry. Many types of bacteria are used to produce lactic acid products, butter and cheese, pickling vegetables, and also in winemaking.

In the chemical industry, bacteria are used to produce alcohols, acetone, and acetic acid.

In medicine, bacteria are used to produce a number of antibiotics, enzymes, hormones and vitamins.

However, bacteria can also cause harm. They not only spoil food, but with their secretions they make it poisonous.

The bacterial organism is represented by one single cell. The forms of bacteria are varied. The structure of bacteria differs from the structure of animal and plant cells.

The cell lacks a nucleus, mitochondria and plastids. The carrier of hereditary information DNA is located in the center of the cell in a folded form. Microorganisms that do not have a true nucleus are classified as prokaryotes. All bacteria are prokaryotes.

It is estimated that there are over a million species of these amazing organisms on earth. To date, about 10 thousand species have been described.

A bacterial cell has a wall, a cytoplasmic membrane, cytoplasm with inclusions and a nucleotide. Of the additional structures, some cells have flagella, pili (a mechanism for adhesion and retention on the surface) and a capsule. Under unfavorable conditions, some bacterial cells are capable of forming spores. The average size of bacteria is 0.5-5 microns.

External structure of bacteria

Rice. 1. The structure of a bacterial cell.

Cell wall

• The cell wall of a bacterial cell is its protection and support. It gives the microorganism its own specific shape.
• The cell wall is permeable. Nutrients pass inward and metabolic products pass through it.
• Some types of bacteria produce special mucus that resembles a capsule that protects them from drying out.
• Some cells have flagella (one or more) or villi that help them move.
• Bacterial cells that appear pink when Gram stained ( gram-negative), the cell wall is thinner and multilayered. Enzymes that help break down nutrients are released.
• Bacteria that appear violet on Gram staining ( gram-positive), the cell wall is thick. Nutrients that enter the cell are broken down in the periplasmic space (the space between the cell wall and the cytoplasmic membrane) by hydrolytic enzymes.
• There are numerous receptors on the surface of the cell wall. Cell killers - phages, colicins and chemical compounds - are attached to them.
• Wall lipoproteins in some types of bacteria are antigens called toxins.
• With long-term treatment with antibiotics and for a number of other reasons, some cells lose their membranes, but retain the ability to reproduce. They acquire a rounded shape - L-shape and can persist in the human body for a long time (cocci or tuberculosis bacilli). Unstable L-forms have the ability to return to their original form (reversion).

Rice. 2. The photo shows the structure of the bacterial wall of gram-negative bacteria (left) and gram-positive bacteria (right).

Capsule

Under unfavorable environmental conditions, bacteria form a capsule. The microcapsule adheres tightly to the wall. It can only be seen in an electron microscope. The macrocapsule is often formed by pathogenic microbes (pneumococci). In Klebsiella pneumoniae, the macrocapsule is always found.

Rice. 3. In the photo is pneumococcus. Arrows indicate the capsule (electronogram of an ultrathin section).

Capsule-like shell

The capsule-like shell is a formation loosely associated with the cell wall. Thanks to bacterial enzymes, the capsule-like shell is covered with carbohydrates (exopolysaccharides) from the external environment, which ensures the adhesion of bacteria to different surfaces, even completely smooth ones.

For example, streptococci, when entering the human body, are able to stick to teeth and heart valves.

The functions of the capsule are varied:

• protection from aggressive environmental conditions,
• ensuring adhesion (sticking) to human cells,
• Possessing antigenic properties, the capsule has a toxic effect when introduced into a living organism.

Rice. 4. Streptococci are capable of sticking to tooth enamel and, together with other microbes, cause caries.

Rice. 5. The photo shows damage to the mitral valve due to rheumatism. The cause is streptococci.

Flagella

• Some bacterial cells have flagella (one or more) or villi that help them move. The flagella contain contractile protein flagellin.
• The number of flagella can be different - one, a bundle of flagella, flagella at different ends of the cell or over the entire surface.
• Movement (random or rotational) is carried out as a result of the rotational movement of the flagella.
• The antigenic properties of flagella have a toxic effect in disease.
• Bacteria that do not have flagella, when covered with mucus, are able to glide. Aquatic bacteria contain 40-60 vacuoles filled with nitrogen.

They provide diving and ascent. In the soil, the bacterial cell moves through soil channels.

Rice. 6. Scheme of attachment and operation of the flagellum.

Rice. 7. The photo shows different types of flagellated microbes.

Rice. 8. The photo shows different types of flagellated microbes.

Drank

• Pili (villi, fimbriae) cover the surface of bacterial cells. The villus is a helically twisted thin hollow thread of protein nature.
• Drank general type provide adhesion (sticking) to host cells. Their number is huge and ranges from several hundred to several thousand. From the moment of attachment, any .
• Sex drank facilitate the transfer of genetic material from the donor to the recipient. Their number is from 1 to 4 per cell.

Rice. 9. The photo shows E. coli. Flagella and pili are visible. The photo was taken using a tunneling microscope (STM).

Rice. 10. The photo shows numerous pili (fimbriae) of cocci.

Rice. 11. The photo shows a bacterial cell with fimbriae.

Cytoplasmic membrane

• The cytoplasmic membrane is located under the cell wall and is a lipoprotein (up to 30% lipids and up to 70% proteins).
• Different bacterial cells have different membrane lipid compositions.
• Membrane proteins perform many functions. Functional proteins are enzymes due to which the synthesis of its various components, etc. occurs on the cytoplasmic membrane.
• The cytoplasmic membrane consists of 3 layers. The phospholipid double layer is permeated with globulins, which ensure the transport of substances into the bacterial cell. If its function is disrupted, the cell dies.
• The cytoplasmic membrane takes part in sporulation.

Rice. 12. The photo clearly shows a thin cell wall (CW), a cytoplasmic membrane (CPM) and a nucleotide in the center (the bacterium Neisseria catarrhalis).

Internal structure of bacteria

Rice. 13. The photo shows the structure of a bacterial cell. The structure of a bacterial cell differs from the structure of animal and plant cells - the cell lacks a nucleus, mitochondria and plastids.

Cytoplasm

The cytoplasm is 75% water, the remaining 25% is mineral compounds, proteins, RNA and DNA. The cytoplasm is always dense and motionless. It contains enzymes, some pigments, sugars, amino acids, a supply of nutrients, ribosomes, mesosomes, granules and all sorts of other inclusions. In the center of the cell, a substance is concentrated that carries hereditary information - the nucleoid.

Granules

The granules are made up of compounds that are a source of energy and carbon.

Mesosomes

Mesosomes are cell derivatives. They have different shapes - concentric membranes, vesicles, tubes, loops, etc. Mesosomes have a connection with the nucleoid. Participation in cell division and sporulation is their main purpose.

Nucleoid

A nucleoid is an analogue of a nucleus. It is located in the center of the cell. It contains DNA, the carrier of hereditary information in a folded form. Unwound DNA reaches a length of 1 mm. The nuclear substance of a bacterial cell does not have a membrane, a nucleolus or a set of chromosomes, and does not divide by mitosis. Before dividing, the nucleotide is doubled. During division, the number of nucleotides increases to 4.

Rice. 14. The photo shows a section of a bacterial cell. A nucleotide is visible in the central part.

Plasmids

Plasmids are autonomous molecules coiled into a ring of double-stranded DNA. Their mass is significantly less than the mass of a nucleotide. Despite the fact that hereditary information is encoded in the DNA of plasmids, they are not vital and necessary for the bacterial cell.

Rice. 15. The photo shows a bacterial plasmid. The photo was taken using an electron microscope.

Ribosomes

Ribosomes of a bacterial cell are involved in the synthesis of protein from amino acids. The ribosomes of bacterial cells are not united into the endoplasmic reticulum, like those of cells with a nucleus. It is ribosomes that often become the “target” for many antibacterial drugs.

Inclusions

Inclusions are metabolic products of nuclear and non-nuclear cells. They represent a supply of nutrients: glycogen, starch, sulfur, polyphosphate (valutin), etc. Inclusions often, when painted, take on a different appearance than the color of the dye. You can diagnose by currency.

Shapes of bacteria

The shape of the bacterial cell and its size have great importance during their identification (recognition). The most common shapes are spherical, rod-shaped and convoluted.

Table 1. Main forms of bacteria.

Globular bacteria

The spherical bacteria are called cocci (from the Greek coccus - grain). They are arranged one by one, two by two (diplococci), in packets, in chains, and like bunches of grapes. This location depends on the method of cell division. The most harmful microbes are staphylococci and streptococci.

Rice. 16. In the photo there are micrococci. The bacteria are round, smooth, and white, yellow and red in color. In nature, micrococci are ubiquitous. They live in different cavities of the human body.

Rice. 17. The photo shows diplococcus bacteria - Streptococcus pneumoniae.

Rice. 18. The photo shows Sarcina bacteria. Coccoid bacteria cluster together in packets.

Rice. 19. The photo shows streptococcus bacteria (from the Greek “streptos” - chain).

Arranged in chains. They are causative agents of a number of diseases.

Rice. 20. In the photo, the bacteria are “golden” staphylococci. Arranged like “bunches of grapes”. The clusters are golden in color. They are causative agents of a number of diseases.

Rod-shaped bacteria

Rod-shaped bacteria that form spores are called bacilli. They have a cylindrical shape. The most prominent representative of this group is the bacillus. The bacilli include plague and hemophilus influenzae. The ends of rod-shaped bacteria may be pointed, rounded, chopped off, flared, or split. The shape of the sticks themselves can be regular or irregular. They can be arranged one at a time, two at a time, or form chains. Some bacilli are called coccobacilli because they have a round shape. But, nevertheless, their length exceeds their width.

Diplobacillus are double rods. Anthrax bacilli form long threads (chains).

The formation of spores changes the shape of the bacilli. In the center of the bacilli, spores form in butyric acid bacteria, giving them the appearance of a spindle. In tetanus bacilli - at the ends of the bacilli, giving them the appearance of drumsticks.

Rice. 21. The photo shows a rod-shaped bacterial cell. Multiple flagella are visible. The photo was taken using an electron microscope. Negative.

Rice. 24. In butyric acid bacilli, spores are formed in the center, giving them the appearance of a spindle. In tetanus sticks - at the ends, giving them the appearance of drumsticks.

Twisted bacteria

No more than one whorl has a cell bend. Several (two, three or more) are campylobacters. Spirochetes have a peculiar appearance, which is reflected in their name - “spira” - bend and “hate” - mane. Leptospira (“leptos” - narrow and “spera” - gyrus) are long filaments with closely spaced curls. Bacteria resemble a twisted spiral.

Rice. 27. In the photo, a spiral-shaped bacterial cell is the causative agent of “rat bite disease.”

Rice. 28. In the photo, Leptospira bacteria are the causative agents of many diseases.

Rice. 29. In the photo, Leptospira bacteria are the causative agents of many diseases.

Club-shaped

Corynebacteria, the causative agents of diphtheria and listeriosis, have a club-shaped form. This shape of the bacterium is given by the arrangement of metachromatic grains at its poles.

Rice. 30. The photo shows corynebacteria.

Read more about bacteria in the articles:

Bacteria have lived on planet Earth for more than 3.5 billion years. During this time they learned a lot and adapted to a lot. The total mass of bacteria is enormous. It is about 500 billion tons. Bacteria have mastered almost all known biochemical processes. The forms of bacteria are varied. The structure of bacteria has become quite complex over millions of years, but even today they are considered the most simply structured single-celled organisms.

Bacteria are the oldest known group of organisms. Layered stone structures - stromatolites - dated in some cases to the beginning of the Archaeozoic (Archaean), i.e. which arose 3.5 billion years ago are the result of the vital activity of bacteria, usually photosynthetic, so-called blue-green algae. Precambrian stromatolite

Similar structures (bacterial films impregnated with carbonates) are still formed today, mainly off the coast of Australia, the Bahamas, in the California and Persian Gulfs, but they are relatively rare and do not reach large sizes, because herbivorous organisms, such as gastropods, feed on them.

The first nucleated cells evolved from bacteria approximately 1.4 billion years ago. The archaeobacteria thermoacidophiles are considered to be the most ancient of existing living organisms. They live in hot spring water that is highly acidic. At temperatures below 55oC (131oF) they die!

The name “bacteria” was introduced by Christian Ehrenberg Christian Ehrenberg in Ehrenberg Christian Gottfried Corresponding Member, Foreign Member, Honorary Member of the RAS

Medical microbiology was further developed in the works of Robert Koch, who formulated general principles determination of the causative agent of the disease (Koch's postulates). In 1905 he was awarded the Nobel Prize for his research on tuberculosis Robert Koch postulates Koch 1905Nobel Prize for tuberculosis ROBERT KOCH (Koch, Robert) (1843–1910),

The foundations of general microbiology and the study of the role of bacteria in nature were laid by M. V. Beyerinck and M. V. Beyerink S. N. Vinogradsky.S. N. Vinogradsky BEYERINK Martin (), Dutch botanist VINOGRADSKY Sergey Nikolaevich (1/ , Kyiv, – , Paris)

According to the shape of the cells, they can be: spherical (cocci) cocci rod-shaped (bacillus, clostridia, pseudomonads) bacilli clostridia pseudomonads convoluted (vibrios, spirillum, spirochetes) vibrios spirillum spirochetes stellate tetrahedral cubic C- or O-shaped The shape determines such abilities of bacteria as attachment to the surface, mobility, nutrient absorption

They belong to prokaryotes (“pre-nuclear” single-celled organisms) there is no nucleus and most other organelles. The bacterial cell is surrounded by a cell wall and a protective capsule. Rod-shaped bacteria (bacilli) are covered with hairs - saws, which are attached to the nutrient substrate or to other cells.

On average they are 0.5-5 microns. microns Escherichia coli, for example, has dimensions of 0.3-1 by 1-6 microns Escherichia coli Staphylococcus aureus diameter 0.5-1 microns Staphylococcus aureus Bacillus subtilis 0.75 by 2-3 µm. Bacillus subtilis The largest of known bacteria is Thiomargarita namibiensis, reaching a size of 750 microns (0.75 mm). Thiomargarita namibiensis The second is Epulopiscium fishelsoni, which has a diameter of 80 microns and a length of up to 700 microns and lives in the digestive tract of the surgeon fish Acanthurus nigrofuscus. Epulopiscium fishelsoni Achromatium oxaliferum reaches sizes of 33 by 100 microns Achromatium oxaliferum Beggiatoa alba 10 by 50 microns. Beggiatoa alba

Spirochetes can grow up to 250 µm in length with a thickness of 0.7 µm. Spirochetes At the same time, bacteria include the smallest of those with cellular structure organisms. Mycoplasma mycoides has a size of 0.1-0.25 microns, which corresponds to the size of large viruses, for example, tobacco mosaic, cowpox or influenza. Mycoplasma mycoides tobacco mosaic viruses cowpox influenza According to theoretical calculations, a spherical cell with a diameter of less than 0.15-0. 20 microns becomes incapable of independent reproduction, since it physically does not contain all the necessary biopolymers and structures in sufficient quantities.

There are many bacteria in the soil, at the bottom of lakes and oceans - wherever they accumulate. organic matter They live in the cold, when the thermometer is just above zero, and in hot acidic springs with Celsius. Some bacteria tolerate very high salinity with temperatures above 90 degrees; in particular, they are the only organisms found in the Dead Sea.

In the atmosphere they are present in water droplets, and their abundance there usually depends on the dust content of the air. Thus, in cities, rainwater contains much more bacteria than in rural areas. There are few of them in the cold air of high mountains and polar regions, however, they are found even in the lower layer of the stratosphere at an altitude of 8 km.

Dividing one cell into two. Under favorable conditions - every minute.

“Spore” - from Greek. “spore” - “seed” Formed under unfavorable conditions (lack of food, moisture, sudden changes in temperature) Easily spread by wind, water, etc. In favorable conditions, the spore becomes a viable bacterium - this is an adaptation to survival in unfavorable conditions.

Participate in the formation of the structure and fertility of soils, soils in the formation of minerals and the destruction of dead plants and animals; minerals maintain reserves of carbon dioxide and oxygen in the atmosphere; atmosphere They are especially important for herbivores, who feed not only on plant food, but on the products of its transformation

The human intestine is normally home to 300 to 1000 species of bacteria with a total mass of up to 1 kg, although 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. Vitamins For thousands of years, people have used lactic acid bacteria to produce cheese, yogurt, kefir, vinegar, and also fermentation. lactic acid bacteria of raw yogurt kefira vinegar pickling

Currently, methods have been developed for the use of phytopathogenic bacteria as safe herbicides, entomopathogenic instead of insecticides. The most widely used is Bacillus thuringiensis, which produces toxins that act on insects. herbicides and insecticides Bacillus thuringiensis In addition to bacterial insecticides, bacterial fertilizers are used in agriculture. bacterial fertilizers Bacteria that cause human diseases are used as biological weapons. biological weapons

Due to their rapid growth and reproduction, as well as their simple structure, bacteria are actively used in scientific research in molecular biology, genetics, genetic engineering and biochemistry. The most well-studied bacterium is Escherichia coli. Information about the metabolic processes of bacteria has made it possible to produce bacterial synthesis of vitamins, hormones, enzymes, antibiotics, etc. molecular biology genetics genetic engineering biochemistry Escherichia coli A promising direction is the enrichment of ores with the help of sulfur-oxidizing bacteria, the purification by bacteria of soils and reservoirs contaminated with oil products or xenobiotics.

Plants and animals are also susceptible to bacterial infections. Many bacteria that are normally safe for humans or even common inhabitants of their skin or intestines, in case of impaired immunity or general weakening of the body, can act as pathogens. immunity

What bacteria are there: types of bacteria, their classification

Bacteria are tiny microorganisms that appeared many thousands of years ago. It is impossible to see microbes with the naked eye, but we should not forget about their existence. There are a huge number of bacilli. The science of microbiology deals with their classification, study, varieties, structural features and physiology.

Microorganisms are called differently, depending on their type of action and function. Under a microscope, you can observe how these small creatures interact with each other. The first microorganisms were quite primitive in form, but their importance should in no case be underestimated. From the very beginning, bacilli developed, created colonies, and tried to survive in changing climatic conditions. Different vibrios are able to exchange amino acids in order to grow and develop normally.

Today it is difficult to say how many species of these microorganisms there are on earth (this number exceeds a million), but the most famous ones and their names are familiar to almost every person. It doesn’t matter what kind of microbes there are or what they are called, they all have one advantage - they live in colonies, which makes it much easier for them to adapt and survive.

First, let's figure out what microorganisms exist. The simplest classification is good and bad. In other words, those that are harmful to the human body cause many diseases, and those that are beneficial. Next we will talk in detail about what the main beneficial bacteria are and give their description.

You can also classify microorganisms according to their shape and characteristics. Many people probably remember that in school textbooks there was a special table depicting various microorganisms, and next to them was the meaning and their role in nature. There are several types of bacteria:

• cocci - small balls that resemble a chain, as they are located one after another;
• rod-shaped;
• spirilla, spirochetes (have a convoluted shape);
• vibrios.

Bacteria of different shapes

We have already mentioned that one of the classifications divides microbes into types depending on their forms.

Bacillus bacteria also have some characteristics. For example, there are rod-shaped types with pointed poles, thickened, rounded or straight ends. As a rule, rod-shaped microbes are very different and are always in chaos, they do not line up in a chain (with the exception of streptobacilli), and do not attach to each other (except for diplobacilli).

Microbiologists include streptococci, staphylococci, diplococci, and gonococci among spherical microorganisms. These can be pairs or long chains of balls.

Curved bacilli are spirilla, spirochetes. They are always active, but do not produce spores. Spirilla is safe for people and animals. You can distinguish spirilla from spirochetes if you pay attention to the number of whorls; they are less convoluted and have special flagella on their limbs.

Types of pathogenic bacteria

For example, a group of microorganisms called cocci, and more specifically streptococci and staphylococci, become the cause of real purulent diseases (furunculosis, streptococcal tonsillitis).

Anaerobes live and develop well without oxygen; for some types of these microorganisms, oxygen becomes fatal. Aerobic microbes require oxygen to thrive.

Archaea are practically colorless single-celled organisms.

You need to beware of pathogenic bacteria, because they cause infections; gram-negative microorganisms are considered resistant to antibodies. There is a lot of information about soil, putrefactive microorganisms, which can be harmful or beneficial.

In general, spirilla are not dangerous, but some species can cause sodoku.

Types of beneficial bacteria

Even schoolchildren know that bacilli can be useful and harmful. People know some names by ear (staphylococcus, streptococcus, plague bacillus). These are harmful creatures that interfere not only external environment, but also to man. There are microscopic bacilli that cause food poisoning.

You definitely need to know useful information about lactic acid, food, and probiotic microorganisms. For example, probiotics, in other words good organisms, are often used in medical purposes. You may ask: for what? They do not allow harmful bacteria to multiply inside a person, strengthen the protective functions of the intestines, and have a good effect on the human immune system.

Bifidobacteria are also very beneficial for the intestines. Lactic acid vibrios include about 25 species. They are found in huge quantities in the human body, but are not dangerous. On the contrary, they protect the gastrointestinal tract from putrefactive and other microbes.

Speaking of good ones, one cannot fail to mention the huge species of streptomycetes. They are known to those who have taken chloramphenicol, erythromycin and similar drugs.

There are microorganisms such as azotobacter. They live in the soil for many years, have a beneficial effect on the soil, stimulate plant growth, and cleanse the soil of heavy metals. They are indispensable in medicine, agriculture, medicine, and the food industry.

Types of bacterial variability

By their nature, microbes are very fickle, they die quickly, they can be spontaneous or induced. We will not go into detail about the variability of bacteria, since this information is more interesting to those who are interested in microbiology and all its branches.

Types of bacteria for septic tanks

Residents of private houses understand the urgent need to purify wastewater, as well as cesspools. Today, you can quickly and efficiently clean drains using special bacteria for septic tanks. This is a huge relief for a person, since cleaning sewers is not a pleasant task.

We have already clarified where biological wastewater treatment is used, and now let’s talk about the system itself. Bacteria for septic tanks are grown in laboratories; they kill the unpleasant odor of wastewater, disinfect drainage wells, cesspools, and reduce the volume Wastewater. There are three types of bacteria that are used for septic tanks:

• aerobic;
• anaerobic;
• live (bioactivators).

Very often people use combined cleaning methods. Strictly follow the instructions on the product, ensuring that the water level is conducive to the normal survival of bacteria. Also remember to use the drain at least once every two weeks to give the bacteria something to eat, otherwise they will die. Don't forget that chlorine from cleaning powders and liquids kills bacteria.

The most popular bacteria are Doctor Robic, Septifos, Waste Treat.

Types of bacteria in urine

In theory, there should be no bacteria in the urine, but after various actions and situations, tiny microorganisms settle wherever they please: in the vagina, in the nose, in water, and so on. If bacteria are detected during tests, this means that the person suffers from diseases of the kidneys, bladder or ureters. There are several ways that microorganisms enter the urine. Before treatment, it is very important to examine and accurately determine the type of bacteria and the route of entry. This can be determined by biological culture of urine, when bacteria are placed in a favorable habitat. Next, the reaction of bacteria to various antibiotics is checked.

We wish you to always remain healthy. Take care of yourself, wash your hands regularly, protect your body from harmful bacteria!