The beneficial bacteria that inhabit the human body are called microbiota. They are quite vast in number - one person has millions of them. Moreover, they all regulate the health and normal functioning of each individual. Scientists say: without beneficial bacteria, or, as they are also called, mutualists, gastrointestinal tract, skin, respiratory tract would instantly be attacked by pathogenic microbes and would be destroyed.
What should be the balance of microbiota in the body and how it can be adjusted to avoid the development of serious diseases, AiF.ru asked General Director of the biomedical holding Sergei Musienko.
Intestinal Workers
One of the important areas where beneficial bacteria are located is the intestines. It is not without reason that it is believed that this is where the entire human immune system is founded. And if the bacterial environment is disturbed, then the body’s defenses are significantly reduced.
Beneficial intestinal bacteria create literally unbearable living conditions for pathogenic microbes - an acidic environment. In addition, beneficial microorganisms help digest plant foods, since bacteria feed on plant cells containing cellulose, but intestinal enzymes cannot cope with this alone. Also, intestinal bacteria contribute to the production of vitamins B and K, which ensure metabolism in bones and connective tissues, as well as release energy from carbohydrates and promote the synthesis of antibodies and regulation of the nervous system.
Most often, when talking about beneficial intestinal bacteria, they mean the 2 most popular types: bifidobacteria and lactobacilli. At the same time, they cannot be called the main ones, as many people think - their number is only 5-15% of total number. However, they are very important, since their positive effect on other bacteria has been proven, when such bacteria can be important factors in the well-being of an entire community: if they are fed or introduced into the body with fermented milk products - kefirs or yoghurts, they help other important bacteria to survive and reproduce . For example, it is very important to restore their population during dysbacteriosis or after a course of antibiotics. Otherwise, it will be problematic to increase the body’s defenses.
Biological shield
The bacteria that inhabit the skin and respiratory tract of humans, in fact, stand guard and reliably protect their area of responsibility from the penetration of pathogenic organisms. The main ones are micrococci, streptococci and staphylococci.
The skin microbiome has undergone changes over the past hundreds of years, as humans have moved from a natural life in contact with nature to regular washing with special products. It is believed that human skin is now inhabited by completely different bacteria that lived before. The body, with the help of the immune system, can distinguish dangerous from non-dangerous. But, on the other hand, any streptococcus can become pathogenic for a person, for example, if it gets into a cut or any other open wound on the skin. An excess of bacteria or their pathological activity on the skin and in the respiratory tract can lead to the development of various diseases, and to the appearance of an unpleasant odor. Today there are developments based on bacteria that oxidize ammonium. Their use makes it possible to seed the skin microbiome with completely new organisms, as a result of which not only the smell disappears (the result of the metabolism of urban flora), but also the structure of the skin changes - pores open, etc.
Saving the microworld
The microcosm of each person changes quite quickly. And this has undoubted advantages, since the number of bacteria can be updated independently.
Different bacteria feed on different substances - the more varied a person’s food and the more it corresponds to the season, the more choice beneficial microorganisms have. However, if food is heavily loaded with antibiotics or preservatives, bacteria will not survive, because these substances are precisely designed to destroy them. Moreover, it does not matter at all that most of the bacteria are not pathogenic. As a result, the diversity of a person’s inner world is destroyed. And after this, various diseases begin - problems with stool, skin rashes, metabolic disorders, allergic reactions, etc.
But the microbiota can be helped. Moreover, it will take only a few days for a slight correction.
There are a large number of probiotics (with live bacteria) and prebiotics (substances that support bacteria). But the main problem is that they work differently for everyone. Analysis shows that their effectiveness against dysbiosis is up to 70-80%, that is, one or another drug may work, or it may not. And here you should carefully monitor the progress of treatment and administration - if the remedies work, you will immediately notice improvements. If the situation remains unchanged, it is worth changing the treatment program.
Alternatively, you can undergo special testing that studies the genomes of bacteria, determines their composition and ratio. This allows you to quickly and competently select the necessary nutritional option and additional therapy, which will restore the fragile balance. Although a person does not feel slight disturbances in the balance of bacteria, they still affect health - in this case, frequent illnesses, drowsiness, and allergic manifestations can be noted. Every city resident, to one degree or another, has an imbalance in the body, and if he does not do anything specifically to restore it, then he will probably have health problems from a certain age.
Fasting, fasting, more vegetables, porridge from natural cereals in the morning - these are just a few options for eating behavior that beneficial bacteria love. But for each person, the diet should be individual in accordance with the state of his body and his lifestyle - only then can he maintain an optimal balance and always feel good.
BACTERIA
a large group of unicellular microorganisms characterized by the absence of a cell nucleus surrounded by a membrane. At the same time, the genetic material of the bacterium (deoxyribonucleic acid, or DNA) occupies a very specific place in the cell - a zone called the nucleoid. Organisms with such a cell structure are called prokaryotes (“prenuclear”), in contrast to all others - eukaryotes (“true nuclear”), whose DNA is located in the nucleus surrounded by a shell. Bacteria, previously considered microscopic plants, are now classified into the independent kingdom Monera - one of five in the current classification system, along with plants, animals, fungi and protists.
Fossil evidence. Bacteria are probably the oldest known group of organisms. Layered stone structures - stromatolites - dated in some cases to the beginning of the Archeozoic (Archean), i.e. arose 3.5 billion years ago, - the result of the vital activity of bacteria, usually photosynthesizing, the so-called. blue-green algae. 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. Nowadays, stromatolites grow mainly where these animals are absent due to high salinity of water or for other reasons, but before the emergence of herbivorous forms during the evolution, they could reach enormous sizes, constituting an essential element of oceanic shallow water, comparable to modern coral reefs. In some ancient rocks, tiny charred spheres have been found, which are also believed to be the remains of bacteria. The first nuclear ones, i.e. eukaryotic, cells evolved from bacteria approximately 1.4 billion years ago.
Ecology. Bacteria are abundant in the soil, at the bottom of lakes and oceans - wherever organic matter accumulates. They live in the cold, when the thermometer is just above zero, and in hot acidic springs with temperatures above 90 ° C. Some bacteria tolerate very high salinity; 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 correlates with the dustiness of the air. Yes, 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. The digestive tract of animals is densely populated with bacteria (usually harmless). Experiments have shown that they are not necessary for the life of most species, although they can synthesize some vitamins. However, in ruminants (cows, antelopes, sheep) and many termites, they are involved in the digestion of plant food. Additionally, the immune system of an animal raised under sterile conditions does not develop normally due to lack of bacterial stimulation. The normal bacterial flora of the intestines is also important for suppressing harmful microorganisms that enter there.
STRUCTURE AND LIFE ACTIVITY OF BACTERIA
Bacteria are much smaller than the cells of multicellular plants and animals. Their thickness is usually 0.5-2.0 microns, and their length is 1.0-8.0 microns. Some forms are barely visible at the resolution of standard light microscopes (approximately 0.3 microns), but species are also known with a length of more than 10 microns and a width that also goes beyond the specified limits, and a number of very thin bacteria can exceed 50 microns in length. On the surface corresponding to the point marked with a pencil, a quarter of a million medium-sized representatives of this kingdom will fit.
Structure. Based on their morphological features, the following groups of bacteria are distinguished: cocci (more or less spherical), bacilli (rods or cylinders with rounded ends), spirilla (rigid spirals) and spirochetes (thin and flexible hair-like forms). Some authors tend to combine the last two groups into one - spirilla. Prokaryotes differ from eukaryotes mainly in the absence of a formed nucleus and the typical presence of only one chromosome - a very long circular DNA molecule attached at one point to the cell membrane. Prokaryotes also do not have membrane-enclosed intracellular organelles called mitochondria and chloroplasts. In eukaryotes, mitochondria produce energy during respiration, and photosynthesis occurs in chloroplasts (see also CELL). In prokaryotes, the entire cell (and primarily the cell membrane) takes on the function of a mitochondrion, and in photosynthetic forms, it also takes on the function of a chloroplast. Like eukaryotes, inside bacteria there are small nucleoprotein structures - ribosomes, necessary for protein synthesis, but they are not associated with any membranes. With very few exceptions, bacteria are unable to synthesize sterols, important components of eukaryotic cell membranes. Outside the cell membrane, most bacteria are covered with a cell wall, somewhat reminiscent of the cellulose wall of plant cells, but consisting of other polymers (they include not only carbohydrates, but also amino acids and bacteria-specific substances). This membrane prevents the bacterial cell from bursting when water enters it through osmosis. On top of the cell wall is often a protective mucous capsule. Many bacteria are equipped with flagella, with which they actively swim. Bacterial flagella are structured simpler and somewhat differently than similar structures of eukaryotes.
"TYPICAL" BACTERIAL CELL and its basic structures.
Sensory functions and behavior. Many bacteria have chemical receptors that detect changes in the acidity of the environment and the concentration of various substances, such as sugars, amino acids, oxygen and carbon dioxide. Each substance has its own type of such “taste” receptors, and the loss of one of them as a result of mutation leads to partial “taste blindness”. Many motile bacteria also respond to temperature fluctuations, and photosynthetic species respond to changes in light intensity. Some bacteria perceive the direction of field lines magnetic field, including the Earth’s magnetic field, with the help of particles of magnetite (magnetic iron ore - Fe3O4) present in their cells. In water, bacteria use this ability to swim along lines of force in search of a favorable environment. Conditioned reflexes bacteria are unknown, but they have a certain kind of primitive memory. While swimming, they compare the perceived intensity of the stimulus with its previous value, i.e. determine whether it has become larger or smaller, and, based on this, maintain the direction of movement or change it.
Reproduction and genetics. Bacteria reproduce asexually: the DNA in their cell is replicated (doubled), the cell divides in two, and each daughter cell receives one copy of the parent DNA. Bacterial DNA can also be transferred between non-dividing cells. At the same time, their fusion (as in eukaryotes) does not occur, the number of individuals does not increase, and usually only a small part of the genome (a complete set of genes) is transferred to another cell, in contrast to the “real” sexual process, in which the descendant receives a complete set of genes from each parent. This DNA transfer can occur in three ways. During transformation, the bacterium absorbs from environment“naked” DNA that got there during the destruction of other bacteria or was deliberately “slipped” by the experimenter. The process is called transformation because in the early stages of its study the main attention was paid to the transformation (transformation) of harmless organisms into virulent ones in this way. DNA fragments can also be transferred from bacteria to bacteria by special viruses - bacteriophages. This is called transduction. A process reminiscent of fertilization and called conjugation is also known: bacteria are connected to each other by temporary tubular outgrowths (copulatory fimbriae), through which DNA passes from a “male” cell to a “female” one. Sometimes bacteria contain very small additional chromosomes - plasmids, which can also be transferred from individual to individual. If the plasmids contain genes that cause resistance to antibiotics, they speak of infectious resistance. She is important with medical point vision, since it can spread between different species and even genera of bacteria, as a result of which the entire bacterial flora, say, of the intestines, becomes resistant to the action of certain drugs.
METABOLISM
Partly due to the small size of bacteria, their metabolic rate is much higher than that of eukaryotes. Under the most favorable conditions, some bacteria can double their total weight and numbers approximately every 20 minutes. This is explained by the fact that a number of their most important enzyme systems function at a very high speed. Thus, a rabbit needs a matter of minutes to synthesize a protein molecule, while bacteria take seconds. However, in a natural environment, for example in soil, most bacteria are “on a starvation diet”, so if their cells divide, it is not every 20 minutes, but once every few days.
Nutrition. Bacteria are autotrophs and heterotrophs. Autotrophs (“self-feeding”) do not need substances produced by other organisms. As the main or single source carbon they use its dioxide (CO2). Including CO2 and other inorganic substances, in particular ammonia (NH3), nitrates (NO-3) and various connections sulfur, into complex chemical reactions, they synthesize all the biochemical products they need. Heterotrophs ("feeding on others") use organic (carbon-containing) substances synthesized by other organisms, in particular sugars, as the main source of carbon (some species also need CO2). When oxidized, these compounds supply energy and molecules necessary for cell growth and functioning. In this sense, heterotrophic bacteria, which include the vast majority of prokaryotes, are similar to humans.
Main sources of energy. If mainly light energy (photons) is used for the formation (synthesis) of cellular components, then the process is called photosynthesis, and species capable of it are called phototrophs. Phototrophic bacteria are divided into photoheterotrophs and photoautotrophs depending on which compounds - organic or inorganic - serve as their main source of carbon. Photoautotrophic cyanobacteria (blue-green algae), like green plants, break down water molecules (H2O) using light energy. This releases free oxygen (1/2O2) and produces hydrogen (2H+), which can be said to convert carbon dioxide (CO2) into carbohydrates. Green and purple sulfur bacteria use light energy to break down other inorganic molecules, such as hydrogen sulfide (H2S), rather than water. The result also produces hydrogen, which reduces carbon dioxide, but no oxygen is released. This type of photosynthesis is called anoxygenic. Photoheterotrophic bacteria, such as purple nonsulfur bacteria, use light energy to produce hydrogen from organic substances, in particular isopropanol, but their source can also be H2 gas. If the main source of energy in the cell is the oxidation of chemicals, the bacteria are called chemoheterotrophs or chemoautotrophs, depending on whether the molecules serve as the main source of carbon - organic or inorganic. For the former, organic matter provides both energy and carbon. Chemoautotrophs obtain energy from the oxidation of inorganic substances, such as hydrogen (to water: 2H4 + O2 in 2H2O), iron (Fe2+ in Fe3+) or sulfur (2S + 3O2 + 2H2O in 2SO42- + 4H+), and carbon from CO2. These organisms are also called chemolithotrophs, thereby emphasizing that they “feed” on rocks.
Breath. Cellular respiration is the process of releasing chemical energy stored in “food” molecules for its further use in vital reactions. Respiration can be aerobic and anaerobic. In the first case, it requires oxygen. It is needed for the work of the so-called. electron transport system: electrons move from one molecule to another (energy is released) and ultimately join oxygen along with hydrogen ions - water is formed. Anaerobic organisms do not need oxygen, and for some species of this group it is even poisonous. The electrons released during respiration attach to other inorganic acceptors, such as nitrate, sulfate or carbonate, or (in one form of such respiration - fermentation) to a specific organic molecule, in particular glucose. See also METABOLISM.
CLASSIFICATION
In most organisms, a species is considered to be a reproductively isolated group of individuals. In a broad sense, this means that representatives of a given species can produce fertile offspring by mating only with their own kind, but not with individuals of other species. Thus, the genes of a particular species, as a rule, do not extend beyond its boundaries. However, in bacteria, gene exchange can occur between individuals not only different types, but also of different genera, so whether it is legitimate to apply the usual concepts of evolutionary origin and kinship here is not entirely clear. Due to this and other difficulties, there is no generally accepted classification of bacteria yet. Below is one of the widely used variants.
KINGDOM OF MONERA
Phylum Gracilicutes (thin-walled gram-negative bacteria)
Class Scotobacteria (non-photosynthetic forms, such as myxobacteria) Class Anoxyphotobacteria (non-oxygen-producing photosynthetic forms, such as purple sulfur bacteria) Class Oxyphotobacteria (oxygen-producing photosynthetic forms, such as cyanobacteria)
Phylum Firmicutes (thick-walled gram-positive bacteria)
Class Firmibacteria (hard-celled forms, such as clostridia)
Class Thallobacteria (branched forms, e.g. actinomycetes)
Phylum Tenericutes (Gram-negative bacteria without a cell wall)
Class Mollicutes (soft-celled forms, such as mycoplasmas)
Phylum Mendosicutes (bacteria with defective cell walls)
Class Archaebacteria (ancient forms, e.g. methane-forming)
Domains. Recent biochemical studies have shown that all prokaryotes are clearly divided into two categories: a small group of archaebacteria (Archaebacteria - "ancient bacteria") and all the rest, called eubacteria (Eubacteria - "true bacteria"). It is believed that archaebacteria, compared to eubacteria, are more primitive and closer to the common ancestor of prokaryotes and eukaryotes. They differ from other bacteria in several significant features, including the composition of ribosomal RNA (rRNA) molecules involved in protein synthesis, the chemical structure of lipids (fat-like substances) and the presence in the cell wall of some other substances instead of the protein-carbohydrate polymer murein. In the above classification system, archaebacteria are considered only one of the types of the same kingdom, which unites all eubacteria. However, according to some biologists, the differences between archaebacteria and eubacteria are so profound that it is more correct to consider archaebacteria within Monera as a special subkingdom. Recently, an even more radical proposal has appeared. Molecular analysis has revealed such significant differences in gene structure between these two groups of prokaryotes that some consider their presence within the same kingdom of organisms to be illogical. In this regard, it is proposed to create a taxonomic category (taxon) of an even higher rank, calling it a domain, and divide all living things into three domains - Eucarya (eukaryotes), Archaea (archaebacteria) and Bacteria (current eubacteria).
ECOLOGY
The two most important ecological functions of bacteria are nitrogen fixation and mineralization of organic residues.
Nitrogen fixation. The binding of molecular nitrogen (N2) to form ammonia (NH3) is called nitrogen fixation, and the oxidation of the latter to nitrite (NO-2) and nitrate (NO-3) is called nitrification. These are vital processes for the biosphere, since plants need nitrogen, but they can only absorb its bound forms. Currently approximately 90% (approx. 90 million tons) annual quantity Such “fixed” nitrogen is provided by bacteria. The rest is produced by chemical plants or occurs during lightning strikes. Nitrogen in the air, which is approx. 80% of the atmosphere is bound mainly by the gram-negative genus Rhizobium and cyanobacteria. Rhizobium species enter into symbiosis with approximately 14,000 species of leguminous plants (family Leguminosae), which include, for example, clover, alfalfa, soybeans and peas. These bacteria live in the so-called. nodules - swellings formed on the roots in their presence. Bacteria obtain organic substances (nutrition) from the plant, and in return supply the host with fixed nitrogen. Over the course of a year, up to 225 kg of nitrogen per hectare is fixed in this way. Non-legume plants, such as alder, also enter into symbiosis with other nitrogen-fixing bacteria. Cyanobacteria photosynthesize, like green plants, releasing oxygen. Many of them are also capable of fixing atmospheric nitrogen, which is then consumed by plants and ultimately animals. These prokaryotes serve as an important source of fixed nitrogen in the soil in general and rice paddies in the East in particular, as well as its main supplier for ocean ecosystems.
Mineralization. This is the name given to the decomposition of organic residues into carbon dioxide (CO2), water (H2O) and mineral salts. From a chemical point of view, this process is equivalent to combustion, so it requires large amounts of oxygen. IN top layer soil contains from 100,000 to 1 billion bacteria per 1 g, i.e. approximately 2 tons per hectare. Typically, all organic residues, once in the ground, are quickly oxidized by bacteria and fungi. More resistant to decomposition is a brownish organic substance called humic acid, which is formed mainly from lignin contained in wood. It accumulates in the soil and improves its properties.
BACTERIA AND INDUSTRY
Given the variety of chemical reactions bacteria catalyze, it is not surprising that they have been widely used in manufacturing, in some cases since ancient times. Prokaryotes share the glory of such microscopic human assistants with fungi, primarily yeast, which provide most of the processes of alcoholic fermentation, for example, in the production of wine and beer. Now that it has become possible to introduce useful genes into bacteria, causing them to synthesize valuable substances such as insulin, the industrial application of these living laboratories has received a new powerful incentive. See also GENETIC ENGINEERING.
Food industry. Currently, bacteria are used by this industry mainly for the production of cheeses, other fermented milk products and vinegar. The main chemical reactions here are the formation of acids. Thus, when producing vinegar, bacteria of the genus Acetobacter oxidize the ethyl alcohol contained in cider or other liquids to acetic acid. Similar processes occur when sauerkraut is sauerkraut: anaerobic bacteria ferment the sugars contained in the leaves of this plant to lactic acid, as well as acetic acid and various alcohols.
Ore leaching. Bacteria are used for leaching of low-grade ores, i.e. transferring them into a salt solution valuable metals, primarily copper (Cu) and uranium (U). An example is the processing of chalcopyrite, or copper pyrite (CuFeS2). Heaps of this ore are periodically watered with water, which contains chemolithotrophic bacteria of the genus Thiobacillus. During their life activity, they oxidize sulfur (S), forming soluble copper and iron sulfates: CuFeS2 + 4O2 in CuSO4 + FeSO4. Such technologies greatly simplify the extraction of valuable metals from ores; in principle, they are equivalent to the processes that occur in nature during the weathering of rocks.
Waste recycling. Bacteria also serve to convert waste materials, such as sewage, into less hazardous or even useful products. Wastewater is one of the most pressing problems of modern humanity. Their complete mineralization requires huge amounts of oxygen, and in ordinary reservoirs where it is customary to dump this waste, there is no longer enough oxygen to “neutralize” it. The solution lies in additional aeration of the wastewater in special pools (aeration tanks): as a result, the mineralizing bacteria have enough oxygen to completely decompose organic matter, and in the most favorable cases, one of the end products of the process becomes drinking water. The insoluble sediment remaining along the way can be subjected to anaerobic fermentation. To ensure that such water treatment plants take up as little space and money as possible, a good knowledge of bacteriology is necessary.
Other uses. To other important areas industrial applications bacteria includes, for example, flax lobe, i.e. separation of its spinning fibers from other parts of the plant, as well as the production of antibiotics, in particular streptomycin (bacteria of the genus Streptomyces).
COMBATING BACTERIA IN INDUSTRY
Bacteria are not only beneficial; The fight against their mass reproduction, for example in food products or in the water systems of pulp and paper mills, has become a whole area of activity. Food spoils under the influence of bacteria, fungi and its own enzymes that cause autolysis ("self-digestion"), unless they are inactivated by heat or other means. Because main reason Since spoilage is still caused by bacteria, the development of effective food storage systems requires knowledge of the endurance limits of these microorganisms. One of the most common technologies is pasteurization of milk, which kills bacteria that cause, for example, tuberculosis and brucellosis. The milk is kept at 61-63°C for 30 minutes or at 72-73°C for only 15 seconds. This does not impair the taste of the product, but inactivates pathogenic bacteria. Wine, beer and fruit juices can also be pasteurized. The benefits of storing food in the cold have long been known. Low temperatures do not kill bacteria, but they do prevent them from growing and reproducing. True, when frozen, for example, to -25 ° C, the number of bacteria decreases after a few months, but a large number of these microorganisms still survive. At temperatures just below zero, bacteria continue to multiply, but very slowly. Their viable cultures can be stored almost indefinitely after lyophilization (freeze-drying) in a protein-containing medium, such as blood serum. Other known methods of storing food include drying (drying and smoking), adding large amounts of salt or sugar, which is physiologically equivalent to dehydration, and pickling, i.e. placing in a concentrated acid solution. When the acidity of the environment corresponds to pH 4 and below, the vital activity of bacteria is usually greatly inhibited or stopped.
BACTERIA AND DISEASES
STUDYING BACTERIA
Many bacteria are easy to grow in so-called. culture medium, which may include meat broth, partially digested protein, salts, dextrose, whole blood, its serum and other components. The concentration of bacteria in such conditions usually reaches about a billion per cubic centimeter, causing the environment to become cloudy. To study bacteria, it is necessary to be able to obtain their pure cultures, or clones, which are the offspring of a single cell. This is necessary, for example, to determine what type of bacteria infected the patient and what antibiotic this type is sensitive to. Microbiological samples, such as throat or wound swabs, blood samples, water samples or other materials, are highly diluted and applied to the surface of a semi-solid medium: on it, round colonies develop from individual cells. The hardening agent for the culture medium is usually agar, a polysaccharide obtained from certain seaweeds that is not digestible by almost any type of bacteria. Agar media is used in the form of “shoals”, i.e. inclined surfaces formed in test tubes standing at a large angle when the molten culture medium solidifies, or in the form thin layers in glass Petri dishes - flat round vessels, closed with a lid of the same shape, but slightly larger in diameter. Usually, within a day, the bacterial cell manages to multiply so much that it forms a colony that is easily visible to the naked eye. It can be transferred to another environment for further study. All culture media must be sterile before starting to grow bacteria, and in the future measures should be taken to prevent the settlement of unwanted microorganisms on them. To examine bacteria grown in this way, heat a thin wire loop in a flame, touch it first to a colony or smear, and then to a drop of water applied to a glass slide. Having evenly distributed the taken material in this water, the glass is dried and quickly passed over the burner flame two or three times (the side with the bacteria should be facing up): as a result, the microorganisms, without being damaged, are firmly attached to the substrate. Dye is dripped onto the surface of the preparation, then the glass is washed in water and dried again. Now you can examine the sample under a microscope. Pure cultures of bacteria are identified mainly by their biochemical characteristics, i.e. determine whether they form gas or acids from certain sugars, whether they are able to digest protein (liquefy gelatin), whether they require oxygen for growth, etc. They also check whether they are stained with specific dyes. Sensitivity to certain medicines, for example, antibiotics, can be determined by placing small disks of filter paper soaked in these substances on a surface infested with bacteria. If any chemical compound kills bacteria, a bacteria-free zone is formed around the corresponding disk.
Collier's Encyclopedia. - Open Society. 2000 .
The human intestine is home to microorganisms that make up a total mass of up to two kilograms. They form the local flora. The ratio is strictly maintained on the principle of expediency.
Bacterial contents are heterogeneous in function and significance for the host organism: some bacteria in all conditions provide support through the proper functioning of the intestines, and therefore are called beneficial. Others are only waiting for the slightest disruption in control and weakening of the body in order to turn into a source of infection. They are called opportunistic.
The introduction of foreign bacteria into the intestines that can cause disease is accompanied by a violation of the optimal balance, even if the person is not sick, but is a carrier of the infection.
Treatment of the disease with medications, especially antibacterial drugs, has a detrimental effect not only on the causative agents of the disease, but also on beneficial bacteria. The problem arises of how to eliminate the consequences of therapy. Therefore, scientists created large group new drugs that supply live bacteria to the intestines.
What bacteria form the intestinal flora?
About five thousand species of microorganisms live in the human digestive tract. They perform following functions:
- They help with their enzymes to break down substances found in foods until they are properly digested and absorbed through the intestinal wall into the bloodstream;
- destroy unnecessary residues of food digestion, toxins, toxic substances, gases in order to prevent rotting processes;
- produce special enzymes for the body, biologically active substances (biotin), vitamin K and folic acid, which are necessary for life;
- participate in the synthesis of immune components.
Studies have shown that some bacteria (bifidobacteria) protect the body from cancer.
Probiotics gradually displace pathogenic microbes, depriving them of nutrition and directing immune cells to them
The main beneficial microorganisms include: bifidobacteria (comprising 95% of the total flora), lactobacilli (almost 5% by weight), Escherichia. The following are considered opportunistic:
- staphylococci and enterococci;
- mushrooms of the genus Candida;
- clostridia.
They become dangerous when a person’s immunity declines and the acid-base balance in the body changes. Examples of harmful or pathogenic microorganisms are Shigella and Salmonella - the causative agents of typhoid fever and dysentery.
Beneficial live bacteria for the intestines 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 the consequences of the negative effects of drugs.
Types of probiotics
Preparations with live bacteria were gradually improved and updated in properties and composition. In pharmacology, they are usually divided into generations. The first generation includes medicines, containing only one strain of microorganisms: Lactobacterin, Bifidumbacterin, Colibacterin.
The second generation is formed by antagonist drugs containing unusual flora that can resist pathogenic bacteria and support digestion: Baktistatin, Sporobacterin, Biosporin.
The third generation includes multicomponent drugs. They contain several strains of bacteria with bioadditives. The group includes: Linex, Atsilakt, Acipol, Bifiliz, Bifiform. The fourth generation consists only of preparations from bifidobacteria: Florin Forte, Bifidumbacterin Forte, Probifor.
Based on their 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, Atsilakt, Acipol, Biobakton, Lebenin, Gastrofarm;
- colibacteria - Colibacterin, Bioflor, Bifikol;
- enterococci - Linex, Bifiform, dietary supplements of domestic production;
- yeast-like fungi - Biosporin, Baktisporin, Enterol, Baktisubtil, Sporobacterin.
What should you consider when purchasing probiotics?
Pharmacological companies in Russia and abroad can produce identical analogue drugs under different names. Imported ones are, of course, much more expensive. Studies have shown that people living in Russia are more adapted to local strains of bacteria.
It’s still better to buy your own drugs
Another negative is that, 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, consultation with a specialist is required. This is caused by serious complications from improper use of drugs. Patients registered:
- exacerbation of cholelithiasis 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 and vitamins to improve digestion and stimulate the growth of beneficial microflora. They are often prescribed for constipation in children and adults.
The group includes those known to practicing doctors: Lactulose, pantothenic acid, Hilak forte, Lysozyme, inulin preparations. Experts believe that it is necessary to combine prebiotics with probiotic preparations to achieve maximum results. For this purpose, combination drugs (synbiotics) have been created.
Characteristics of first generation probiotics
Preparations from the group of first-generation probiotics are prescribed to young children when first-degree dysbiosis is detected, as well as when 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 others, since it is produced in the USA
The pediatrician chooses Bifidumbacterin, Lactobacterin (includes bifidobacteria and lactobacilli) for infants. They are diluted in warm boiled water and given 30 minutes before breastfeeding. For older children and adults, medications in capsules and tablets are suitable.
Colibacterin - contains dried E. coli bacteria, used for prolonged colitis in adults. The more modern single drug Biobakton contains acidophilus bacillus and is indicated starting from the neonatal period.
Narine, Narine Forte, Narine in milk concentrate - contains the 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 living bacteria, but include other microorganisms that can suppress and destroy pathogenic microflora - yeast-like fungi and bacilli spores.
It is used mainly for the treatment of children with mild dysbacteriosis and intestinal infections. The duration of the course should be no more than seven days, then switch to live bacteria of the first group. Baktisubtil (French drug) and Flonivin BS contain bacillus spores with a wide spectrum of antibacterial action.
Spores are not destroyed inside the stomach hydrochloric acid and enzymes, reach the small intestine intact
Bactisporin and Sporobacterin are made from Bacillus subtilis, retaining antagonistic properties to pathogenic pathogens and resistance to the action of the antibiotic Rifampicin.
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 saprophytic bacteria.
Features of third generation probiotics
Live bacteria or several strains of them collected in combination are more active. Used for the treatment of acute intestinal disorders of moderate severity.
Linex - contains bifidobacteria, lactobacilli and enterococci, 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 (lyophilisate), rectal suppositories.
The drug contains bifidobacteria, enterococci, lactulose, vitamins B 1, B 6
How are fourth generation probiotics different?
When producing preparations with bifidobacteria of this group, the need to create additional protection for the digestive tract and relieve intoxication was taken into account. The products are called “sorbed” because the active bacteria are located on the particles activated carbon.
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, available in capsules and powders.
Effectively protects and restores the intestinal flora after respiratory infections, acute gastroenterological pathology, dysbacteriosis. The drug is contraindicated in people with congenital deficiency of the lactase enzyme or 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. Prescribed for severe forms of intestinal infection, diseases of the large intestine, and dysbacteriosis.
It has been proven that the effectiveness in diseases caused by Shigella is equal to that of fluoroquinolone antibiotics. Can replace the combination of Enterol and Bifiliz. Florin Forte - includes lacto- and bifidobacterial composition, sorbed on coal. Available in capsule and powder form.
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, they include a prebiotic, which creates favorable conditions for the growth of beneficial bacteria.
The fact is that the effect of probiotics does not last long. After the intestinal microflora is restored, they may die, which again causes the situation to worsen. Accompanying prebiotics feed beneficial bacteria, ensure active growth and protection.
Many synbiotics are considered dietary supplements rather than medicinal substances. Do right choice Only a specialist can. It is not recommended to make treatment decisions on your own. The drugs in this series include the following.
Lb17
Many authors refer to the most the best drugs to date. It combines the beneficial effects of 17 types of living bacteria with extracts of algae, mushrooms, vegetables, medicinal herbs, fruits, grains (more than 70 components). Recommended for course use, you need to take from 6 to 10 capsules per day.
Production does not involve sublimation and drying, so the viability of all bacteria is preserved. The drug is obtained by natural fermentation for three years. Strains of bacteria work in different areas digestion. Suitable for lactose intolerant people, gluten and gelatin free. Supplied to the pharmacy chain from Canada.
Multidophilus plus
Includes three strains of lactobacilli, one - bifidobacteria, maltodextrin. Made in the USA. Available in capsules for adults. The Polish product Maxilac contains: oligofructose as a prebiotic, and live cultures of beneficial bacteria as a probiotic (three strains of bifidobacteria, five strains of lactobacilli, streptococcus). Indicated for diseases of the gastrointestinal tract, respiratory system, and impaired immunity.
Prescribed for children from three years of age and adults, 1 capsule in the evening with meals.
Which probiotics have target indications?
With an abundance of information about bacterial preparations with living microorganisms, some people rush to extremes: either they do not believe in the advisability of use, or, conversely, they spend money on products of little use. It is necessary to consult a specialist about the use of probiotics in a specific situation.
Children with diarrhea during breastfeeding (especially those born prematurely) are prescribed liquid probiotics. They also help with irregular bowel movements, constipation, and retarded physical development.
Children in such situations are shown:
- Bifidumbacterin Forte;
- Linux;
- Acipol;
- Lactobacterin;
- Biphilis;
- Probifor.
If a child’s diarrhea is associated with a previous respiratory disease, pneumonia, infectious mononucleosis, or false croup, then these drugs are prescribed in a short course for 5 days. For viral hepatitis, treatment lasts from a week to a month. Allergic dermatitis is treated in 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.
Bifidumbacterin Forte and Bifiliz are most suitable for preventive use during the season of increased morbidity.
What is best to take for dysbiosis?
To be sure of a violation of the intestinal flora, it is necessary to take a stool test for dysbacteriosis. The doctor must determine which specific bacteria the body lacks and how severe the disorders are.
If a deficiency of lactobacilli is established, it is not necessary to use only drugs. containing them. Because it is bifidobacteria that determine the imbalance and form the rest of the microflora.
Monopreparations, which contain only the same type of bacteria, are recommended by a doctor only when mild degree violations
In severe cases, combined agents of the third and fourth generations are necessary. Probifor is most indicated (infectious enterocolitis, colitis). For children, it is always necessary to select combinations of drugs with lacto- and bifidobacteria.
Products containing colibacteria are prescribed very carefully. When identifying ulcers in the intestines and stomach, acute gastroenteritis, probiotics with lactobacilli are more indicated.
Typically, the doctor determines the duration of treatment based on the generation of the probiotic:
- I – a monthly course is required.
- II – from 5 to 10 days.
- III – IV - up to seven days.
If there is no effectiveness, the specialist changes the treatment regimen, adds antifungals and antiseptics. Use of probiotics - modern approach to the treatment of many diseases. This is especially important for parents of young children to remember. It is necessary to distinguish medicines from biological food additives. Existing dietary supplements with intestinal bacteria can only be used by a healthy person for the purpose of prevention.
Bacteria appeared approximately 3.5-3.9 billion years ago, they were the first living organisms on our planet. Over time, life developed and became more complex - new ones appeared, each time more complex shapes organisms. Bacteria did not stand aside all this time; on the contrary, they were the most important component of the evolutionary process. They were the first to develop new forms of life support, such as respiration, fermentation, photosynthesis, catalysis... and also found effective ways coexistence with almost every living creature. Man was no exception.
But bacteria are an entire domain of organisms, numbering more than 10,000 species. Each species is unique and has followed its own evolutionary path, and as a result has developed its own unique forms of coexistence with other organisms. Some bacteria have entered into close mutually beneficial cooperation with humans, animals and other creatures - they can be called useful. Other species have learned to exist at the expense of others, using the energy and resources of donor organisms - they are generally considered harmful or pathogenic. Still others have gone even further and become practically self-sufficient; they receive everything they need for life from the environment.
Inside humans, like inside other mammals, there live an unimaginably large number of bacteria. There are 10 times more of them in our bodies than all the cells of the body combined. Among them, the absolute majority are useful, but the paradox is that their vital activity, their presence within us is a normal state of affairs, they depend on us, we, in turn, on them, and at the same time we do not feel any signs of this cooperation. Another thing is harmful, for example, pathogenic bacteria, once inside us their presence immediately becomes noticeable, and the consequences of their activity can become very serious.
Beneficial bacteria
The vast majority of them are creatures that live in symbiotic or mutualistic relationships with donor organisms (within which they live). Typically, such bacteria take on some of the functions that the host body is not capable of. An example is bacteria that live in the human digestive tract and process part of the food that the stomach itself is not able to cope with.
Some types of beneficial bacteria:
Escherichia coli (lat. Escherichia coli)
It is an integral part of the intestinal flora of humans and most animals. Its benefits are difficult to overestimate: it breaks down indigestible monosaccharides, promoting digestion; synthesizes vitamins K; prevents the development of pathogenic and pathogenic microorganisms in the intestines.
Macro photo: colony of Escherichia coli bacteria
Lactic acid bacteria (Lactococcus lactis, Lactobacillus acidophilus, etc.)
Representatives of this order are present in milk, dairy and fermented products, and at the same time are part of the intestinal and oral microflora. They are capable of fermenting carbohydrates and in particular lactose and producing lactic acid, which is the main source of carbohydrates for humans. By maintaining a constantly acidic environment, the growth of unfavorable bacteria is inhibited.
Bifidobacteria
Bifidobacteria have the most significant effect on infants and mammals, constituting up to 90% of their intestinal microflora. Through the production of milk and acetic acids they completely prevent the development of putrefactive and pathogenic microbes in the child’s body. In addition, bifidobacteria: promote the digestion of carbohydrates; provide protection of the intestinal barrier from the penetration of microbes and toxins into the internal environment of the body; synthesize various amino acids and proteins, vitamins K and B, useful acids; promote intestinal absorption of calcium, iron and vitamin D.
Harmful (pathogenic) bacteria
Some types of pathogenic bacteria:
Salmonella typhi
This bacterium is the causative agent of a very acute intestinal infection, typhoid fever. Salmonella typhi produces toxins that are harmful exclusively to humans. When infected, general intoxication of the body occurs, which leads to severe fever, rash throughout the body, and in severe cases, damage to the lymphatic system and, as a result, death. Every year, 20 million cases of typhoid fever are recorded worldwide, 1% of cases lead to death.
Colony of Salmonella typhi bacteria
Tetanus bacillus (Clostridium tetani)
This bacterium is one of the most persistent and at the same time the most dangerous in the world. Clostridium tetani produces an extremely toxic poison, tetanus exotoxin, which leads to almost complete damage to the nervous system. People with tetanus experience terrible pain: all the muscles of the body spontaneously tense to the limit, and powerful convulsions occur. The mortality rate is extremely high - on average, about 50% of those infected die. Fortunately, a tetanus vaccine was invented back in 1890; it is given to newborns in all developed countries of the world. In underdeveloped countries, tetanus kills 60,000 people every year.
Mycobacteria (Mycobacterium tuberculosis, Mycobacterium leprae, etc.)
Mycobacteria are a family of bacteria, some of which are pathogenic. Various representatives of this family cause such dangerous diseases as tuberculosis, mycobacteriosis, leprosy (leprosy) - all of them are transmitted by airborne droplets. Every year, mycobacteria cause more than 5 million deaths.
Rice. 1. The human body consists of 90% 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). Bakteroides gingivalis, causes periodontitis ( lilac color). Candida albicus (yellow color). 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. The epithelium and lymphoid elements of the small intestine are affected. 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 (blue coccobacteria). 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 learned to protect food long-term storage by sterilization, 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 protect them from unfavorable environmental conditions for many years. 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 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. In a spore-like state, it persists in the external environment for a 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. The activity of these fungi causes great damage in 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. Brownie Merulius mushroom 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 appearing bad smell 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 breeding 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. mold fungi.
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, can cause 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.
To study the harmful effects of microorganisms on the body and develop preventive measures is the task of man!
