What are bacteria: names and types. Bacteria - a general characteristic. Classification, structure, nutrition and the role of bacteria in nature

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Bacteria are microorganisms that form a huge invisible world around and inside us. They are notorious for their detrimental effects, while the beneficial effects they produce are rarely spoken of. This article gives general description some good and bad bacteria.

“For the first half of geologic time, our ancestors were bacteria. Most creatures are still bacteria, and each of our trillions of cells is a colony of bacteria.” – Richard Dawkins

bacteria- the most ancient living organisms on Earth are ubiquitous. The human body, the air we breathe, the surfaces we touch, the food we eat, the plants that surround us, our environment, and so on. - all this is inhabited by bacteria.

Approximately 99% of these bacteria are beneficial, while the rest have a bad reputation. In fact, some bacteria are very important for the proper development of other living organisms. They can exist either on their own or in symbiosis with animals and plants.

The list of harmful and beneficial bacteria below includes some of the most well-known beneficial and deadly bacteria.

Beneficial bacteria

Lactic acid bacteria / Dederlein sticks

Characteristic: Gram-positive, rod-shaped.

Habitat: Varieties of lactic acid bacteria are present in milk and dairy products, fermented foods, and are part of the oral, intestinal, and vaginal microflora. The most predominant species are L. acidophilus, L. reuteri, L. plantarum, etc.

Benefit: Lactic acid bacteria are known for their ability to use lactose and produce lactic acid as a waste by-product. This ability to ferment lactose makes lactic acid bacteria an important ingredient in the preparation of fermented foods. They are also an integral part of the brining process, as lactic acid can serve as a preservative. Through what is called fermentation, yogurt is obtained from milk. Certain strains are even used to make yoghurts on an industrial scale. In mammals, lactic acid bacteria contribute to the breakdown of lactose during the digestive process. The resulting acidic environment prevents the growth of other bacteria in body tissues. Therefore, lactic acid bacteria are an important component of probiotic preparations.

bifidobacteria

Characteristic: Gram-positive, branched, rod-shaped.

Habitat: Bifidobacteria are present in the human gastrointestinal tract.

Benefit: Like lactic acid bacteria, bifidobacteria also produce lactic acid. In addition, they produce acetic acid. This acid inhibits the growth of pathogenic bacteria by controlling the pH level in the intestines. B. longum, a type of bifidobacteria, promotes the breakdown of hard-to-digest plant polymers. The bacteria B. longum and B. infantis help prevent diarrhea, candidiasis, and even fungal infections in infants and children. Thanks to these useful properties, they are also often included in probiotic preparations sold in pharmacies.

E. coli (E. coli)

Characteristic:

Habitat: E. coli is part of normal microflora large and small intestine.

Benefit: E. coli aids in the breakdown of undigested monosaccharides, thus aiding in digestion. This bacterium produces vitamin K and biotin, which are essential for various cellular processes.

Note: Certain strains of E. coli can cause severe toxic effects, diarrhea, anemia, and kidney failure.

Streptomycetes

Characteristic: Gram-positive, filamentous.

Habitat: These bacteria are present in soil, water, and decaying organic matter.

Benefit: Certain streptomycetes (Streptomyces spp.) play an important role in soil ecology by decomposing the organic matter present in it. For this reason, they are being studied as a bioremedial agent. S. aureofaciens, S. rimosus, S. griseus, S. erythraeus, and S. venezuelae are commercially important varieties that are used to produce antibacterial and antifungal compounds.

Mycorrhiza / Nodule bacteria

Characteristic:

Habitat: Mycorrhiza are present in the soil, existing in symbiosis with the root nodules of leguminous plants.

Benefit: Bacteria Rhizobium etli, Bradyrhizobium spp., Azorhizobium spp. and many other varieties are useful for fixing atmospheric nitrogen, including ammonia. This process makes this substance available to plants. Plants do not have the ability to use atmospheric nitrogen and depend on nitrogen-fixing bacteria that are present in the soil.

cyanobacteria

Characteristic: Gram-negative, rod-shaped.

Habitat: Cyanobacteria are mainly aquatic bacteria, but they are also found on bare rocks and in soil.

Benefit: Cyanobacteria, also known as blue-green algae, are a group of bacteria that are very important for environment. They fix nitrogen in aquatic environment. Their calcification and decalcification abilities make them important for maintaining balance in the coral reef ecosystem.

harmful bacteria

Mycobacteria

Characteristic: are neither gram-positive nor gram-negative (due to high lipid content), rod-shaped.

Diseases: Mycobacteria are pathogens that have long time doubling. M. tuberculosis and M. leprae, the most dangerous varieties, are the causative agents of tuberculosis and leprosy, respectively. M. ulcerans causes ulcerated and non-ulcerated skin nodules. M. bovis can cause tuberculosis in livestock.

tetanus bacillus

Characteristic:

Habitat: Tetanus bacillus spores are found in the soil, on the skin, and in the digestive tract.

Diseases: Tetanus bacillus is the causative agent of tetanus. It enters the body through a wound, multiplies in it, and releases toxins, in particular tetanospasmin (also known as spasmogenic toxin) and tetanolysin. This leads to muscle spasms and respiratory failure.

Plague wand

Characteristic: Gram-negative, rod-shaped.

Habitat: The plague bacillus can only survive in its host, particularly in rodents (fleas) and mammals.

Diseases: The plague wand causes bubonic plague and plague pneumonia. The skin infection caused by this bacterium takes the bubonic form, characterized by malaise, fever, chills, and even convulsions. Infection of the lungs caused by bubonic plague causes plague pneumonia, which causes coughing, difficulty breathing, and fever. According to the WHO, between 1,000 and 3,000 cases of plague occur worldwide each year. The plague agent is recognized and studied as a potential biological weapon.

Helicobacter pylori

Characteristic: Gram-negative, rod-shaped.

Habitat: Helicobacter pylori colonizes the mucous membrane of the human stomach.

Diseases: This bacterium is the main cause of gastritis and peptic ulcers. It produces cytotoxins and ammonia, which damage the lining of the stomach, causing abdominal pain, nausea, vomiting, and bloating. Helicobacter pylori is present in half of the world's population, but most people remain asymptomatic, and only a few develop gastritis and ulcers.

Anthrax

Characteristic: Gram-positive, rod-shaped.

Habitat: Anthrax is widely distributed in the soil.

Diseases: Anthrax infection results in a deadly disease called anthrax. Infection occurs as a result of inhalation of anthrax endospores. Anthrax mainly occurs in sheep, goats, cattle, etc. However, in rare cases, transmission of the bacterium from livestock to humans occurs. The most common symptoms of anthrax are sores, fever, headache, abdominal pain, nausea, diarrhea, etc.

We are surrounded by bacteria, some of them harmful, others beneficial. And it depends only on us how effectively we coexist with these tiny living organisms. It is in our power to benefit from beneficial bacteria by avoiding the overuse and inappropriate use of antibiotics, and to stay away from harmful bacteria by taking appropriate preventive measures, such as personal hygiene and routine medical check-ups.

Video

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

Types of bacteria

In school biology textbooks there are images of different types of bacteria that differ in shape:

Cocci are spherical organisms that differ in mutual arrangement. Under a microscope, it is noticeable that streptococci represent a chain of balls, diplococci live in pairs, staphylococci are clusters of arbitrary shape. A number of cocci cause various inflammatory processes entering 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 defense against external influences and are safe if the balance of the flora is observed.
Rod-shaped differ in shape, size and ability to spore formation. The spore-forming species are called bacilli. Bacilli include: tetanus bacillus, anthrax bacillus. Spores are formations within a microorganism. Spores are insensitive to chemical treatment, their resistance to external influences is the key to the preservation of the species. It is known that spores are destroyed at high temperature (above 120ºС).

Forms of rod-shaped microbes:

with pointed poles, as in Fusobacterium, which is part of the normal microflora of the upper respiratory tract;
with thickened poles, resembling a mace, as in Corynebacterium - the causative agent of diphtheria;
with rounded ends, such as in Escherichia coli, which is necessary for the digestion process;
with straight ends, like anthrax.

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 bond with the staining substance, which is enhanced by exposure to iodine. Gram-negative, on the contrary, are not susceptible to the dye, their shell is firmly protected.

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

Aerobic and anaerobic

How bacteria live

Biologists define bacteria in a separate kingdom, they are different from other living things. it unicellular organism no core inside. Their shape can be in the form of a ball, cone, stick, spiral. Prokaryotes use flagella to move.

Biofilm is a city for microorganisms, it 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 between two media: liquid and air, liquid and liquid. The initial step is reversible and film formation can be prevented.
Fixation - Bacteria secrete polymers, ensuring their strong fixation, form a matrix for strength and protection.
Maturation - microbes merge, exchange nutrients, develop microcolonies.
Growth stage - there is an accumulation of bacteria, their fusion, displacement. The number of microorganisms is from 5 to 35%, the rest of the space is occupied by the extracellular matrix.
Dispersion - Microorganisms periodically detach from the film, which attach to other surfaces and form a biofilm.

The processes that take place in a biofilm are different from what happens to a microbe, which is not integral part colonies. Colonies are stable, microbes organize a single system of behavioral reactions, determining the interaction of members inside the matrix and outside the film. Human mucous membranes are inhabited by a large number of microorganisms that produce a gel for protection and ensure the stability of the functioning of organs. An example is the lining of the stomach. It is known that Helicobacter pylori, which are considered the cause of gastric ulcer, is present in more than 80% of the examined people, but not everyone develops peptic ulcer. It is assumed that Helicobacter pylori, being members of the colony, are involved in digestion. Their ability to cause harm is manifested only after certain conditions are created.

The interaction of bacteria in biofilms is still poorly understood. But already today, some microbes have become human assistants in carrying out restoration work, 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 in the future will also generate electricity.

At this very moment, man, as you read these lines, you are benefiting from the work of bacteria. From the oxygen we breathe in to the nutrients our stomach extracts from food, we have bacteria to thank for thriving on this planet. There are about ten times more microorganisms in our body, including bacteria, than our own cells. In fact, we are more microbes than humans.

Only recently have we begun to slowly understand microscopic organisms and their impact on our planet and health, but history shows that centuries ago our ancestors used the power of bacteria to ferment food and drink (had anyone heard of bread and beer?).

In the 17th century, we began to study bacteria already directly in our bodies in close connection with us - in the mouth. Anthony van Leeuwenhoek's curiosity led to the discovery of the bacteria when he examined a plaque between his own teeth. Van Leeuwenhoek described bacteria poetically, describing the bacterial colony on his teeth as "a little white substance, like hardened dough". By placing the sample under a microscope, van Leeuwenhoek saw that the microorganisms were moving. So they are alive!

You should know that bacteria have played a crucial role for the Earth, becoming key point in creating breathable air and the biological wealth of the planet we call home.

In this article, we will provide you with the big picture about these tiny but highly influential micro-organisms. We look at the good, the bad, and the downright bizarre ways that bacteria shape human and environmental history. First, let's look at how bacteria differ from other types of life.

Basics of bacteria

Well, if bacteria are invisible to the naked eye, how can we know so much about them?

Scientists have developed powerful microscopes to look at bacteria - which range in size from one to several microns (a millionth of a meter) - and find out how they relate to other life forms, plants, animals, viruses and fungi.

As you may know, cells are the building blocks of life, they make up both the tissues of our body and the tree that grows outside the window. Humans, animals and plants have cells with genetic information contained in a membrane called the nucleus. These types of cells, called eukaryotic cells, have special organelles, each of which performs a unique job in helping the cell to function.

Bacteria, however, do not have nuclei, and their genetic material (DNA) floats freely within the cell. These microscopic cells lack organelles and have other methods of reproducing and transferring genetic material. Bacteria are considered prokaryotic cells.

Do bacteria survive in an environment with or without oxygen?

Their shape: sticks (bacillus), circles (cocci) or spirals (spirillum)

Are the bacteria Gram-negative or Gram-positive, that is, do they have an outer protective membrane that prevents staining of the inside of the cell

How bacteria move and explore their environment (many bacteria have flagella, tiny whip-like structures that allow them to move around in their environment)

Microbiology - the science of all types of microbes, including bacteria, archaea, fungi, viruses, and protozoa - distinguishes bacteria from their microbial brethren.

The bacteria-like prokaryotes, now classified as archaea, once co-existed with bacteria, but as scientists learned more about them, they gave bacteria and archaea their own categories.

Microbial nutrition (and miasma)

Like humans, animals, and plants, bacteria need food to survive.

Some bacteria - autotrophs - use basic resources like sunlight, water, and chemicals from the environment to create food (think cyanobacteria, which turned sunlight into oxygen for 2.5 million years). Other bacteria are called heterotrophs by scientists because they draw energy from existing organic matter as food (for example, dead leaves on forest soil).

The truth is that what might be tasty to bacteria will be disgusting to us. They have evolved to absorb all types of products, from oil spills and by-products of nuclear fission to human waste and decay products.

But the affinity of bacteria for a particular food source could benefit society. For example, art experts in Italy have turned to bacteria that can eat excess layers of salt and glue that reduce the durability of priceless works of art. The ability of bacteria to process organic matter is also very useful for the Earth, both in soil and in water.

From daily experience, you are very familiar with the odor caused by bacteria ingesting the contents of your wastebasket, digesting leftover food, and releasing their own gaseous by-products. However, everything is not limited to this. You can also blame bacteria for causing those awkward moments when you yourself pass gases.

One big family

Bacteria grow and form colonies when given the chance. If food and environmental conditions are favorable, they multiply and form sticky clumps, called biofilms, to survive on surfaces ranging from rocks to your mouth's teeth.

Biofilms have their pros and cons. On the one hand, they are mutually beneficial to natural objects (mutualism). On the other hand, they can be a serious threat. For example, doctors who treat patients with medical implants and devices are seriously concerned about biofilms, as they are real estate for bacteria. Once colonized, biofilms can produce by-products that are toxic - and sometimes fatal - to humans.

Like people in cities, the cells in the biofilm communicate with each other, exchanging information about food and potential danger. But instead of calling neighbors on the phone, bacteria send notes using chemicals.

Also, bacteria are not afraid to live on their own. Some species have developed interesting ways to survive in harsh conditions. When there is no more food, and conditions become unbearable, the bacteria preserve themselves by creating a tough shell - the endospore, which puts the cell into a dormant state and preserves the genetic material of the bacterium.

Scientists find bacteria in such time capsules that have been stored for 100 or even 250 million years. This suggests that the bacteria can self-storage for a long time.

Now that we know what opportunities colonies provide for bacteria, let's figure out how they get there - by dividing and multiplying.

Reproduction of bacteria

How do bacteria create colonies? Like other life forms on Earth, bacteria need to copy themselves in order to survive. Other organisms do this through sexual reproduction, but not bacteria. But first, let's discuss why variety is good.

Life undergoes natural selection, or the selective forces of a certain environment allow one type to flourish and multiply more than another. You may remember that genes are the mechanism that instructs the cell what to do and determines what color your hair and eyes will be. You get genes from your parents. Sexual reproduction results in mutations, or random changes in DNA, which creates diversity. The greater the genetic diversity, the greater the chance that an organism will be able to adapt to environmental constraints.

For bacteria, reproduction does not depend on meeting the right microbe; they simply copy their own DNA and divide into two identical cells. This process, called binary fission, occurs when one bacterium divides into two, copying its DNA and passing it on to both parts of the split cell.

Since the resulting cell will eventually be identical to the one from which it was born, this method of reproduction is not the best for creating a diverse gene pool. How do bacteria acquire new genes?

It turns out that bacteria use a clever trick: horizontal gene transfer, or the exchange of genetic material without reproduction. There are several ways that bacteria use to do this. One method involves harvesting genetic material from the environment outside the cell - from other microbes and bacteria (through molecules called plasmids). Another way is viruses, which use bacteria as their home. By infecting a new bacterium, viruses leave the genetic material of the previous bacterium in the new one.

The exchange of genetic material gives bacteria the flexibility to adapt, and they adapt if they feel stressful changes in the environment, such as food shortages or chemical changes.

Understanding how bacteria adapt is essential to combat them and develop antibiotics in medicine. Bacteria can exchange genetic material so frequently that sometimes a treatment that worked before no longer works.

No high mountains, no great depth

If you ask the question “where are the bacteria?”, It is easier to ask “where are there no bacteria?”.

Bacteria are found almost everywhere on Earth. It is impossible to imagine the number of bacteria on the planet at the same time, but according to some estimates, their number is (bacteria and archaea together) 5 octillion - this is a number with 27 zeros.

The classification of bacterial species is extremely complex for obvious reasons. Now there are approximately 30,000 officially identified species, but the knowledge base is constantly growing, and there are opinions that we have just the tip of the iceberg for all types of bacteria.

The truth is that bacteria have been around for a very long time. They gave rise to some of the oldest fossils, which are 3.5 billion years old. The results of scientific research suggest that cyanobacteria began to create oxygen approximately 2.3-2.5 billion years ago in the world's oceans, saturating the Earth's atmosphere with oxygen that we breathe to this day.

Bacteria can survive in air, water, soil, ice, heat, plants, intestines, skin - everywhere.

Some bacteria are extremophiles, meaning they can withstand extreme environments where they are either extremely hot or cold or lack the nutrients and chemicals we normally associate with life. Researchers have found such bacteria in Mariana Trench, the deepest point on Earth at the bottom Pacific Ocean, near hydrothermal vents in water and ice. There are also heat-loving bacteria, such as those that color the opalescent pool in Yellowstone National Park.

Bad (for us)

While bacteria make important contributions to human and planetary health, they also have a dark side. Some bacteria can be pathogenic, meaning they can cause illness and disease.

Throughout human history, certain bacteria have (understandably) gotten a bad rap for causing panic and hysteria. Take, for example, the plague. The plague-causing bacterium Yersinia pestis not only killed over 100 million people, but may have contributed to the collapse of the Roman Empire. Before the advent of antibiotics, drugs that help fight bacterial infections, they were very difficult to stop.

Even today, these pathogenic bacteria seriously scare us. By developing resistance to antibiotics, bacteria that cause anthrax, pneumonia, meningitis, cholera, salmonellosis, tonsillitis and other diseases that still remain with us, always pose a danger to us.

This is especially true for Staphylococcus aureus, the bacterium responsible for staph infections. This "superbug" causes many problems in clinics, as patients quite often pick up this infection while inserting medical implants and catheters.

We have already talked about natural selection and how some bacteria produce a variety of genes that help them cope with environmental conditions. If you have an infection and some of the bacteria in your body are different from others, antibiotics can kill most of the bacterial population. But those bacteria that survive will develop resistance to the drug and stay, waiting for the next chance. Therefore, doctors recommend completing the course of antibiotics to the end, and in general, contacting them as rarely as possible, only as a last resort.

Bioweapons are another chilling aspect of this conversation. Bacteria can be used as a weapon in some cases, in particular, anthrax was used at one time. In addition, not only people suffer from bacteria. separate view- Halomonas titanicae - showed an appetite for the sunken ocean liner "Titanic", corroding the metal of the historic ship.

Of course, bacteria can bring more than just harm.

heroic bacteria

Let's explore good side bacteria. After all, these microbes gave us such delicious foods like cheese, beer, sourdough and other fermented items. They also improve human health and are used in medicine.

Individual bacteria can be thanked for shaping human evolution. Science is collecting more and more data about microflora - microorganisms that live in our bodies, especially in digestive system and intestines. Research shows that bacteria, the new genetic materials, and the diversity they bring to our bodies allow humans to adapt to new food sources that weren't used before.

To put it another way, by lining the surface of your stomach and intestines, bacteria work for you. When you eat, bacteria and other microbes help you break down and extract nutrients from food, especially carbohydrates. The more diverse the bacteria we consume, the more diverse our bodies get.

Although our knowledge of our own microbes is very limited, there is reason to believe that the absence of certain microbes and bacteria in the body may be associated with health, metabolism and susceptibility to human allergens. Preliminary studies in mice have shown that metabolic diseases like obesity are associated with diversity and healthy microflora, rather than our prevailing “calories in, calories out” mindset.

The possibility of introducing certain microbes and bacteria into the human body, which can provide certain benefits, is now being actively explored, however, at the time of writing, general recommendations for their use have not yet been established.

In addition, bacteria have played an important role in the development of scientific thought and human medicine. Bacteria played a leading role in the development of Koch's postulates of 1884, which led to the general understanding that diseases are caused by a particular type of microbe.

Researchers studying bacteria accidentally discovered penicillin, an antibiotic that has saved countless lives. Also more recently, in this regard, an easy way to edit the genome of organisms has been discovered, which can revolutionize medicine.

In fact, we are just beginning to understand how to benefit from our cohabitation with these little friends. In addition, it is not clear who is the true owner of the Earth: people or microbes.

Microorganisms live in the human intestine, which make up a total mass of up to two kilograms. They form local flora. The ratio is strictly maintained according to the principle of expediency.

The bacterial content is heterogeneous in function and significance for the host organism: some bacteria in all conditions provide support through the proper functioning of the intestines, therefore they are called beneficial. Others are just waiting for the slightest breakdown in control and weakening of the body in order to turn into a source of infection. They are called opportunistic pathogens.

The introduction of foreign bacteria into the intestines that can cause disease is accompanied by a violation of the optimal balance, even if a person is not sick, but is a carrier of the infection.

Treatment of the disease with medicines, especially antibacterial action, has a detrimental effect not only on the causative agents of the disease, but also on beneficial bacteria. The problem is how to eliminate the consequences of therapy. Therefore, scientists have created a large group of new drugs that supply live bacteria for the intestines.

What bacteria form the intestinal flora?

About half a thousand species of microorganisms live in the human digestive tract. They perform the following functions:

help with their enzymes to break down the substances that have got with the products to normal absorption, absorption through the intestinal wall into the bloodstream;
produce the destruction of unnecessary residues of the digestion of food, toxins, toxic substances, gases, in order to prevent the processes of decay;
produce special enzymes for the body, biologically active substances(biotin), vitamin K and folic acid, which are essential for life;
participate in the synthesis of immune components.

Studies have shown that some bacteria (bifidobacteria) protect the body from cancer.

Probiotics gradually crowd out pathogenic microbes, depriving them of nutrition and directing immune cells to them.

The main beneficial microorganisms include: bifidobacteria (make up 95% of the entire flora), lactobacilli (almost 5% by weight), Escherichia. Conditionally pathogenic are:

staphylococci and enterococci;
mushrooms of the genus Candida;
clostridia.

They become dangerous when a person's immunity falls, a change in the acid-base balance in the body. An example of harmful or pathogenic microorganisms are shigella, salmonella - the causative agents of typhoid fever, dysentery.

Beneficial live bacteria for the gut are also called probiotics. So, they began to call specially created substitutes for normal intestinal flora. Another name is eubiotics.
Now they are effectively used to treat digestive pathologies and consequences. negative impact medicines.

Types of Probiotics

Preparations with live bacteria were gradually improved and updated in terms of properties and composition. In pharmacology, they are usually divided into generations. The first generation includes drugs containing only one strain of microorganisms: Lactobacterin, Bifidumbacterin, Colibacterin.

The second generation is formed by antagonist preparations containing an unusual flora that can resist pathogenic bacteria and support digestion: Bactistatin, Sporobacterin, Biosporin.

The third generation includes multicomponent drugs. They contain several strains of bacteria with bioadditives. The group includes: Lineks, Atsilakt, Acipol, Bifiliz, Bifiform. The fourth generation consists only of preparations from bifidobacteria: Florin Forte, Bifidumbacterin Forte, Probifor.

According to the bacterial composition, probiotics can be divided into those containing as the main component:

bifidobacteria - Bifidumbacterin (forte or powder), Bifiliz, Bifikol, Bifiform, Probifor, Biovestin, Lifepack Probiotics;
lactobacilli - Linex, Lactobacterin, Atsilact, Acipol, Biobacton, Lebenin, Gastrofarm;
colibacteria - Colibacterin, Bioflor, Bifikol;
enterococci - Linex, Bifiform, dietary supplements domestic production;
yeast-like fungi - Biosporin, Baktisporin, Enterol, Baktisubtil, Sporobacterin.

What should be considered when buying probiotics?

Under different names, pharmacological firms in Russia and abroad can produce the same drugs-analogues. Imported, of course, much more expensive. Studies have shown that people living in Russia are more adapted to local strains of bacteria.

Still better to buy your own drugs

Another negative - as it turned out, imported probiotics contain only a fifth of the declared volume of living microorganisms and do not settle in the intestines of patients for a long time. Before purchasing, you need to consult a specialist. This is caused by serious complications from the misuse of drugs. Patients reported:

exacerbation of gallstone and urolithiasis;
obesity;
allergic reactions.

Live bacteria should not be confused with prebiotics. These are also medicines, but do not contain microorganisms. Prebiotics contain enzymes, vitamins to improve digestion, stimulate the growth of beneficial microflora. They are often prescribed for constipation in children and adults.

The group includes known to practitioners: Lactulose, pantothenic acid, Hilak forte, Lysozyme, preparations from inulin. Experts believe that it is necessary to combine prebiotics with probiotic preparations for maximum results. For this, combined preparations (synbiotics) have been created.

Characterization of first generation probiotics

Preparations from the group of probiotics of the first generation are prescribed to young children when first-degree dysbacteriosis is detected, and also if prevention is necessary, if the patient is prescribed a course of antibiotics.

Primadophilus is an analogue of drugs with two types of lactobacilli, much more expensive than the others, since it is produced in the USA

The pediatrician chooses Bifidumbacterin, Lactobacterin for babies (include bifido- and lactobacilli). They are bred in warm boiled water and give 30 minutes before breastfeeding. Older children and adults are suitable drugs in capsules, tablets.

Colibacterin - contains dried bacteria of Escherichia coli, is used for prolonged colitis in adults. A more modern monopreparation Biobacton contains an acidophilus bacillus, indicated from the neonatal period.

Narine, Narine Forte, Narine in milk concentrate - contains an acidophilic form of lactobacilli. Comes from Armenia.

Purpose and Description of Second Generation Probiotics

Unlike the first group, second-generation probiotics do not contain beneficial live bacteria, but include other microorganisms that can suppress and destroy pathogenic microflora - yeast-like fungi and spores of bacilli.

Used mainly for the treatment of children with mild dysbacteriosis and intestinal infections. The duration of the course should be observed for no more than seven days, then switch to live bacteria of the first group. Baktisubtil (a French drug) and Flonivin BS contain bacillus spores with a wide spectrum of antibacterial action.

Inside the stomach, spores are not destroyed by hydrochloric acid and enzymes, they reach the small intestine intact

Baktisporin and Sporobacterin are made from hay bacillus, antagonistic properties to pathogenic pathogens, resistance to the action of the antibiotic Rifampicin are preserved.

Enterol contains yeast-like fungi (saccharomycetes). Comes from France. Used in the treatment of diarrhea associated with antibiotics. Active against clostridia. Biosporin includes two types of saprophyte bacteria.

Features of third generation probiotics

Live bacteria collected in combination or several of their strains act more actively. They are used to treat acute intestinal disorders of moderate severity.

Linex - contains bifidobacteria, lactobacilli and enterococci, is produced in Slovakia in a special powder for children (Linex Baby), capsules, sachets. Bifiform is a Danish drug, several varieties are known (Baby drops, chewable tablets, complex). Bifiliz - contains bifidobacteria and lysozyme. Available in suspension (lyophilizate), rectal suppositories.

As part of the drug bifidobacteria, enterococci, lactulose, vitamins B 1, B 6

How are 4th generation probiotics different?

In the production of preparations with bifidobacteria of this group, the need for additional protection of the digestive tract and the removal of intoxication was taken into account. Means are called "sorbed" because the active bacteria are located on activated carbon particles.

Indicated for respiratory infections, diseases of the stomach and intestines, dysbacteriosis. The most popular drugs in this group. Bifidumbacterin Forte - contains live bifidobacteria sorbed on activated carbon, is available in capsules and powders.

Effectively protects and restores the intestinal flora after respiratory infections, with acute gastroenterological pathology, dysbacteriosis. The drug is contraindicated in people with congenital deficiency of the lactase enzyme, with rotavirus infection.

Probifor - differs from Bifidumbacterin Forte in the number of bifidobacteria, it is 10 times higher than the previous drug. Therefore, the treatment is much more effective. It is prescribed in severe forms of intestinal infection, with diseases of the large intestine, dysbacteriosis.

It has been proven that the effectiveness is equated in diseases caused by shigella to antibiotics of the fluoroquinolone series. Able to replace the combination of Enterol and Bifiliz. Florin Forte - includes a lacto- and bifidobacterium composition sorbed on coal. Available in capsule and powder form.

The use of synbiotics

Synbiotics are a completely new proposal in the treatment of intestinal flora disorders. They provide a double action: on the one hand, they necessarily contain a probiotic, on the other hand, they include a prebiotic that creates favorable conditions for the growth of beneficial bacteria.

The fact is that the action of probiotics is not long-lasting. After the restoration of the intestinal microflora, they can die, which again causes a worsening of the situation. Accompanying prebiotics nourish beneficial bacteria, provide active growth and protection.

Many synbiotics are dietary supplements, not medicinal substances. Only a specialist can make the right choice. It is not recommended to make a decision about treatment on your own. The drugs in this series include the following.

Lb17

Many authors refer to the best drugs to date. It combines the beneficial effect of 17 types of live bacteria with extracts of algae, mushrooms, vegetables, herbs, fruits, cereals (more than 70 components). Recommended for course use, you need to take from 6 to 10 capsules per day.

The production does not involve sublimation and drying, therefore the viability of all bacteria is preserved. The drug is obtained by natural fermentation for three years. Strains of bacteria work in different parts of digestion. Suitable for people with lactose intolerance, does not contain gluten and gelatin. Comes to the pharmacy chain from Canada.

Multidophilus plus

Includes three strains of lactobacilli, one - bifidobacteria, maltodextrin. Produced in the USA. Available in capsules for adults. The Polish remedy Maxilak in its composition contains: as a prebiotic oligofructose, as a probiotic - live cultures of beneficial bacteria (three strains from bifidobacteria, five from lactobacilli, streptococcus). Indicated in diseases of the gastrointestinal tract, respiratory system, impaired immunity.

Assigned to children from the age of three and adults 1 capsule in the evening with meals

Which probiotics have targeted indications?

With an abundance of information about bacterial preparations with live microorganisms, some people rush to extremes: they either do not believe in the expediency of using them, or, conversely, spend money on products of little use. It is necessary to consult a specialist about the use of probiotics in a particular situation.

Children with diarrhea during breastfeeding(especially those born prematurely) prescribe liquid probiotics. They also help with irregular stools, constipation, lagging behind in physical development.

Babies in such situations are shown:

Bifidumbacterin Forte;
Linex;
Acipol;
Lactobacterin;
Bifiliz;
Probifor.

If diarrhea in a child is associated with a past respiratory disease, pneumonia, infectious mononucleosis, false croup, then these drugs are prescribed in a short course for 5 days. With viral hepatitis, treatment lasts from a week to a month. Allergic dermatitis is treated with courses from 7 days (Probifor) to three weeks. A patient with diabetes is recommended to take courses of probiotics of different groups for 6 weeks.

For prophylactic administration, Bifidumbacterin Forte, Bifiliz are most suitable during the season of increased incidence.

What is better to take with dysbacteriosis?

It is necessary to be sure of the violation of the intestinal flora to pass a stool test for dysbacteriosis. The doctor must determine which specific bacteria the body lacks, how severe the violations are.

With an established deficiency of lactobacilli, it is not necessary to use drugs only. containing them. Because it is bifidobacteria that are decisive in the imbalance and form the rest of the microflora.

Monopreparations, in which there are only the same type of bacteria, are recommended by the doctor only with a mild degree of violations.

In severe cases, combined means of the third and fourth generations are needed. The most indicated Probifor (infectious enterocolitis, colitis). For children, it is always necessary to select combinations of drugs with lacto- and bifidobacteria.

Means with colibacilli are prescribed very carefully. When identifying ulcers in the intestines and stomach, acute gastroenteritis, probiotics with lactobacilli are more indicated.

Usually, the doctor determines the duration of treatment by the generation of the probiotic:

I - a monthly course is required.
II - from 5 to 10 days.
III - IV - up to seven days.

In the absence of effectiveness, the specialist changes the treatment regimen, adds antifungal agents, antiseptics. The use of probiotics is a modern approach to the treatment of many diseases. This is especially important for parents of young children. It is necessary to distinguish medicines from biological food supplements. Existing dietary supplements with intestinal bacteria can only be used by a healthy person for the purpose of prevention.

The body of a bacterium is represented by a 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 assumed that on earth there are over a million species of these amazing organisms. To date, about 10 thousand species have been described.

A bacterial cell has a wall, cytoplasmic membrane, cytoplasm with inclusions, and a nucleotide. Of the additional structures, some cells have flagella, pili (a mechanism for sticking together and holding on to the surface), and a capsule. Under adverse conditions, some bacterial cells are able to form spores. The average size of bacteria is 0.5-5 microns.

The 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 specific shape.
The cell wall is permeable. Nutrients pass through it inside and metabolic products (metabolism) out.
Some types of bacteria produce a 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 turn pink on Gram stain ( gram negative), the cell wall is thinner, multilayered. Enzymes that break down nutrients are released to the outside.
Bacteria that turn purple on Gram stain 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 are attached to them - phages, colicins and chemical compounds.
Wall lipoproteins in some types of bacteria are antigens, which are called toxins.
With prolonged treatment with antibiotics and for a number of other reasons, some cells lose their membrane, but retain the ability to reproduce. They acquire a rounded shape - an L-shape and can be stored for a long time in the human body (cocci or tuberculosis bacilli). Unstable L-forms have the ability to return to their original form (reversion).

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

Capsule

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

Rice. 3. In the photo, pneumococcus. The arrows indicate the capsule (electron diffraction pattern 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) of the external environment, which ensures adhesion of bacteria to different surfaces, even completely smooth ones.

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

The functions of the capsule are diverse:

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

Rice. 4. Streptococci are able to stick together with tooth enamel and, together with other microbes, are the cause of caries.

Rice. 5. In the photo, the defeat of the mitral valve in rheumatism. The reason is streptococci.

Flagella

Some bacterial cells have flagella (one or more) or villi that help them move. The flagella contain the contractile protein flagelin.
The number of flagella can be different - one, a bunch 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 the disease.
Bacteria that do not have flagella, being covered with mucus, are able to glide. Aquatic bacteria contain vacuoles in the amount of 40-60, filled with nitrogen.

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

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

Rice. 7. In the photo different types flagellated microbes.

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

drinking

Pili (villi, fimbriae) cover the surface of bacterial cells. The villus is a helically twisted thin hollow thread of protein nature.
General drank provide adhesion (adhesion) with host cells. Their number is huge and ranges from several hundred to several thousand. From the moment of attachment, any .
sex saws promote 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. Visible flagella and drinking. The photo was taken using a tunneling microscope (STM).

Rice. 10. The photo shows numerous pili (fimbriae) in 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 lipid composition of membranes.
Membrane proteins perform many functions. Functional proteins are enzymes due to which the synthesis of its various components occurs on the cytoplasmic membrane, etc.
The cytoplasmic membrane consists of 3 layers. The double phospholipid layer is permeated with globulins, which ensure the transport of substances into the bacterial cell. If it fails, the cell dies.
The cytoplasmic membrane is involved in sporulation.

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

The 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. Have different shape- concentric membranes, vesicles, tubules, loops, etc. Mesosomes have a connection with the nucleoid. Participation in cell division and spore formation is their main purpose.

Nucleoid

The nucleoid is analogous to the nucleus. It is located in the center of the cell. DNA is localized in it - the carrier of hereditary information in a folded form. The untwisted DNA reaches a length of 1 mm. The nuclear substance of a bacterial cell does not have a membrane, a nucleolus and a set of chromosomes, and is not divided by mitosis. Before division, 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 much 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 a bacterial cell.

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

Ribosomes

Ribosomes of a bacterial cell are involved in protein synthesis from amino acids. Ribosomes of bacterial cells are not united in the endoplasmic reticulum, as in cells that have 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. When stained, inclusions often take on a different appearance than the color of the dye. You can diagnose by currency.

Shapes of bacteria

Bacterial cell shape and size great importance during their identification (recognition). The most common forms are spherical, rod-shaped and convoluted.

Table 1. Main forms of bacteria.

globular bacteria

Spherical bacteria are called cocci (from the Greek coccus - grain). They are arranged one at a time, two at a time (diplococci), in bags, chains and like bunches of grapes. This arrangement depends on the mode of cell division. The most harmful microbes are staphylococci and streptococci.

Rice. 16. The photo shows micrococci. Bacteria are round, smooth, white, yellow and red. Micrococci are ubiquitous in nature. They live in different cavities of the human body.

Rice. 17. In the photo, diplococcus bacteria - Streptococcus pneumoniae.

Rice. 18. Sarcina bacteria in the photo. Coccoid bacteria are combined into packets.

Rice. 19. In the photo, streptococcus bacteria (from the Greek "streptos" - a chain).

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

Rice. 20. In the photo, the bacteria are "golden" staphylococci. Arranged like "bunch of grapes". The clusters have a golden color. They are the causative agents of a number of diseases.

rod-shaped bacteria

Rod-shaped bacteria that form spores are called bacilli. They are cylindrical in shape. The most prominent representative of this group is the bacillus. Bacilli include plague and hemophilic rods. The ends of rod-shaped bacteria can be pointed, rounded, truncated, expanded, or split. The shape of the sticks themselves can be correct and incorrect. They can be arranged one at a time, two at a time, or form chains. Some bacilli are called coccobacilli because they are round in shape. But, nevertheless, their length exceeds the width.

Diplobacilli are double rods. Anthrax sticks form long threads (chains).

The formation of spores changes the shape of the bacilli. In the center of the bacilli, spores form in butyric bacteria, giving them the appearance of a spindle. In tetanus sticks - 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 with an electron microscope. Negative.

Rice. 22. In the photo, rod-shaped bacteria forming chains (anthrax rods).