Pirelli - brand history and interesting facts. The modern look of Pirelli

The number and composition of microorganisms in water are determined by the physical and chemical state, the content of nutrients, flora and fauna, the depth of the reservoir, the release of sewage and industrial water without treatment facilities, etc. In relatively clean reservoirs, there are various microorganisms coming from the soil. These include rods, cocci, spirilla, fungi, protozoa, viruses, and plasmids. When a large amount of organic matter enters the water, clostridia and other anaerobes, aerobic bacteria, vibrios, and spirochetes are found in it. Pollution of water bodies with pathogenic, opportunistic microorganisms occurs as a result of the inflow of sewage from coastal settlements, as well as industrial waters rich in organic compounds. The microflora of the soil washed out by ground and surface waters pollutes reservoirs, rivers, lakes and coastal waters of the seas. In addition, the release of sewage from ships, washing clothes, bathing horses, and the ingestion of the corpses of animals that died from infections also contribute to the contamination of water bodies with pathogenic microbes. When water bodies are polluted with sewage, E. coli, Enterobacter, Str.faecalis, Cl. perfringens, etc. Despite the processes of self-purification of water bodies from opportunistic and pathogenic microorganisms, the latter can cause water epidemics, acute intestinal infections: salmonellosis, dysentery, cholera. They occur in case of accidents in the sewer system and the flow of wastewater into open water bodies, especially into the water supply network. Sanitary and hygienic assessment of water is carried out not only by the presence of E. coli in it, but also by the degree of contamination of water with this microbe. To do this, define microbial count of water(the number of microbes in 1 ml of water), if-titer(titer - the smallest amount of water in ml in a cat contains 1 Escherichia coli) and if-index(the number of Escherichia coli in 1 liter of water). To determine if-titer and if-index, the method is used membrane filters (a certain volume of water is filtered through a nitrocellulose filter, which is then inoculated on Endo medium. Kish-I stick gives red colonies with a metallic sheen). The same applies two-phase fermentation method (take 9 samples: 3 samples of 100 ml, 3 samples of 10 ml, 3 of 1 ml and inoculate in Aikman's medium (glucose peptone medium + Andrede indicator). sown on the Endo medium to make sure that it is colibacillus.According to GOST, if the titer is 333, if the index is 3.

Sanitary-indicative water microbes: Escherichia coli, perfringens coli, Proteus, Enterococcus.

2. Humoral immune response: primary, secondary, local, gnt. Development mechanisms.

HUMORAL IMMUNE REACTIONS

Three cell types are involved in humoral immune responses: macrophages (Ag-presenting cells), T-helpers, and B-lymphocytes .

Ag-presenting cells phagocytose the microorganism and process it, splitting it into fragments (Ag processing). Fragments of Ag are displayed on the surface of the Ag-presenting cell along with the MHC molecule. The complex "Ag-molecule MHC class II" is presented to the T-helper. Recognition of the complex by T-helper stimulates the secretion of IL-1 by macrophages.

T-helper under the influence of IL-1 synthesizes IL-2 and receptors for IL-2; the latter by an autocrine mechanism stimulates the proliferation of T-helpers, as well as CTL.

B-lymphocyte. Activation of a B-lymphocyte involves the direct interaction of Ag with an Ig molecule on the surface of a B-cell. In this case, the B-lymphocyte itself processes Ag and presents its fragment in connection with the MHC II molecule on its surface. This complex recognizes the T-helper selected using the same Ag. Recognition by the T-helper receptor of the complex Ag-molecule MHC class II on the surface of the B-lymphocyte leads to the secretion of IL-2, IL-4, IL-5 and γ-IFN by the T-helper, under the influence of which the B-cell multiplies, forming a clone of plasma cells. cells (plasmocytes). Plasma cells synthesize AT . AT secretion is stimulated by IL-6 secreted by activated T-helpers. Some mature B-lymphocytes after antigen-dependent differentiation circulate in the body in the form of memory cells.

Primary answer. The appearance of AT precedes latency period duration 3-5 days. At this time, Ag is recognized and clones of plasma cells are formed. Then comes log phase, corresponding to the entry of AT into the blood; its duration is 7-15 days. Gradually, AT titers reach a peak and stationarynarnayaphase, duration 15-30 days. She is replaced descent phase AT titers lasting 1-6 months. Features primaryno answer -low antibody rateeducation andthe appearance of relatively low titersAT.

secondary response. After antigenic stimulation, some of the B and T lymphocytes circulate as memory cells. Features of the secondary immune response - high rate of antibody formation,appearance of maximum titersATand long(sometimes perennial) theircirculation. The main characteristics of the secondary response: the formation of AT is induced by significantly lower doses of Ag; the inductive phase is reduced to 5-6 hours; among AT, IgG with high affinity dominates, the peak of their formation occurs earlier (3-5 days); AT are formed in higher titers and circulate in the body for a long time.

GNT associated with the production of specific antibodies, has a stereotypical course, which can result in death. Mast cells secrete mediators (serotonin, histamine) can lead to anaphylactic shock. It can manifest itself in the form of atopic diseases, serum sickness, the Arthus phenomenon.

Last week, the health service issued a ban on bathing children in Lake Sukhovlyany. An excess of colimorphic bacteria was found in the water, which can cause infectious diseases in children. Where do bacteria come from and why the recommendations of specialists should not be neglected, the author of the Green Portal of the Grodno region figured out.

The soil is the most populated by microorganisms. However, water is also a natural habitat for many microbes, and among them there are many dangerous to humans. Water is a factor in the transmission of many infectious diseases and a source of the spread of infectious diseases, the emergence of epizootics and epidemics.

The water of open sources is mainly inhabited by microorganisms: rivers, lakes. The more contaminated water is with organic residues, the more microbes it contains.

In our lakes and rivers, along with polluted storm, melt and sewage, untreated urban waste, garbage, both representatives of the normal microflora of humans and animals (E. coli, enterococci, clostridia), and pathogens of intestinal infections (typhoid, paratyphoid, cholera, leptospirosis, enterovirus infections). Some of them can even breed in water - Vibrio cholerae, Legionella.

Bacteriological studies of water mainly consist in the detection of colibacilli (especially E. coli - Escherichia coli) and some other spore-forming bacteria. E. coli is a permanent inhabitant of the intestines of humans and animals, therefore, its presence in drinking water is an indicator of fecal contamination. The higher the concentration of E. coli bacteria, the more likely the presence of bacteria such as salmonella, dysentery and cholera. Their number should not exceed 100 in 1 liter in the bathing area and not more than 20 in 1 liter of pool water and sea water.

There is also a group of microorganisms that constantly live and multiply in water. These include micrococci, sarcins, bacteria of the genus Proteus, Pseudomonas, representatives of the genus Leptospira.

Survival of microorganisms in water is very different and depends on the specific species. So, Shigella, Vibrio cholerae, Brucella retain their viability in water from several days to several weeks. Enteroviruses, hepatitis A virus, salmonella, leptospira - several months. Bacterial spores, like soil, retain their ability to germinate in water for many years. The causative agent of anthrax can persist in water for up to 3 years, the causative agent of tuberculosis for up to 1 year.

There is a group of diseases that are characterized by the water way of distribution (paratyphoid, leptospirosis).

The largest number of microbes in water bodies is found in the surface layers (in a layer of 10 cm from the water surface) of coastal zones. With distance from the coast and increasing depth, the number of microbes decreases. In clean water there are 100-200 microbial cells per 1 ml, and in contaminated water - 100-300 thousand and more.

As for groundwater, they are filtered through the layers of soil and at great depths they will be practically sterile, therefore, if they contain microorganisms, then only in a single amount.

Water is one of the most favorable environments for the life and reproduction of bacteria. Different ponds and reservoirs contain different numbers of bacteria. But everywhere they perform their functions - they maintain balance, provide the ecosystem with nutrients, oxygen, and eliminate organic residues.

According to one of the most common scientific theories, bacteria are called the oldest, quite possibly the first living organisms on Earth. Microbes inhabit even the most extreme places on the planet. For example, anaerobic bacteria do not need oxygen to live. The total mass of bacteria in the Earth's biosphere is approximately 350-550 billion tons.

Microbes were first examined under a microscope by the Dutch naturalist Anthony van Leeuwenhoek in 1676. The metabolism of microorganisms, their physiology began to be investigated by Louis Pasteur, who discovered the pathogenic effect of bacteria on the body.

The most optimal habitat for protozoa, which include anaerobic bacteria, is water. In different water bodies, the composition of bacteria can vary, depending on many factors:

environment temperature,
salt content,
standing water or running water
absence or presence of sunlight.

Microorganisms living in an aquarium, in addition to the harm caused by some species, can have a positive effect. Beneficial microorganisms cleanse the aquarium of ammonia, which is in the waste of its inhabitants. While Nitrosomonas converts the ammonia in the aquarium into nitrite, the genus Nitrobacter converts nitrite into nitrate, purifying the aquarium's stagnant water (and completing the nitrogen cycle). Beneficial saprophyte bacteria do not spoil the water in the aquarium, but on the contrary, they purify it by feeding on rotting algae, food and waste products of fish. Disease-causing (pathogenic) microbes include bacteria such as:

Aeromonas - causes aeromonosis, in which the color of the fish fades, they stop eating. It is treated with the VUS-2 vaccine.

Pseudomonas are opportunistic bacteria. With insufficient nutrition of fish and disturbed biological balance of the environment, ulcers, mucus and death of fish are caused. Can be killed with biseptol.
Edwardsiella tarda - dangerous for goldfish by infection of the intestinal tract, leading to death. It is possible to neutralize these microbes with the help of oxytetracycline and biseptol added to the aquarium water.
A gram-negative rod provokes furunculosis, that is, it forms ulcers in fish. Penetrates into the aquarium with parts of the soil and dirty water. When infected, the fish should be moved to a separate aquarium with a solution of chloramphenicol.

Bacteria in wells

Not a single organism on our planet is able to do without drinking water. But in addition to this function, tap water can pose a threat and be dangerous to the human body. It is made so by the viruses and microorganisms that are in it.

Every drop of drinking water, when viewed under a microscope, contains countless varieties of beneficial and dangerous bacteria and viruses. Complete elimination of them is impossible. Even if we allow the possibility of complete disinfection provided by reverse osmosis and boiling, microbes will again enter the water from the air, faucet, dishes and other places. That is why the criteria for the admissibility of drinking tap water in medical practice are not categorical, but exclude the presence of pathogenic microbes, that is, those that can contribute to the development of the disease.

Pathogenic bacteria are hazardous to human health. This list includes, in particular:

Sallmonella typhi, non-typhi (salmonella);
Shiqella;
Campylobacter coli, C. jejuni;
Vibrio cholerae (Vibrio cholerae) and others.

There are also viruses that live in water. The most contagious is the hepatitis A virus (causes Botkin's disease). About a million people around the world catch this virus every year. The virus infects the liver and spleen. It is removed from the water by reverse osmosis or by using a membrane filter.

Rotaviruses are viruses that live in water and cause a disease popularly called the intestinal flu. It most often affects children, as well as people who care for them. As a result of infection with the virus, general symptoms of intestinal poisoning appear (vomiting, abdominal pain), and the temperature rises. Eliminate the virus from the water easily by boiling.

Determination of microorganisms in drinking water

It is very difficult and costly to determine all microorganisms present in a sample of drinking water from a well. Therefore, in laboratory conditions, the presence of only the most easily detectable representatives of the microflora is determined, which may indicate the presence of other, more dangerous anaerobic bacteria in the water. These include colimorphic microorganisms.

Colimorphic, rod-shaped, Gram-negative microbes enter drinking water and wells mainly with faecal effluents. These include the following names:

Escherichia,
Citrobacter,
enterobacter,
Klebsiella.

The content of colimorphic microbes in tap and drinking water from wells is not allowed. Their presence indicates pollution or insufficient water purification. If these microbes are found under the microscope, a test for the presence of thermotolerant colimorphic bacteria is mandatory.

So, saprophytic bacteria are either initially present in the stagnant water of the well, or get there during the installation of the water supply system. In order to purify drinking water, it is first necessary to analyze the water and take a sample. To take a sample, the container must be decontaminated, hands must be washed with soap, and the tap must also be disinfected. Water from wells should be delivered to the laboratory for analysis no more than two hours after sampling.

Fight against pathogenic bacteria

The easiest way to purify water is to boil it. This is the most affordable and widespread method of getting rid of pathogens. Another way is a chlorine tablet dissolved in water, but you need to take into account the amount of water, as well as the harmfulness of the substance.

The use of iodine is also one way to get rid of microorganisms. To do this, you need to heat the water so that it is warm. After that, an iodine preparation is added to the water and insisted for about half an hour. Another option is ultraviolet.

You can also get rid of anaerobic bacteria without resorting to boiling. One of the most common methods of disinfection is the freezing of water, followed by the production of thawed water. The beneficial properties of melt water have long been known. The method is as simple and good as boiling, but it has an important advantage - melt water does not lose oxygen, which is necessary for the human body. The method of freezing water is quite effective and does not require additional disinfection measures. It should be remembered that by boiling additional melt water, you can not only not get any benefit, but also damage the quality of the water.

How to get rid of anaerobic and other bacteria in drinking or melt water without resorting to boiling and chemical methods? Silver destroys microbes from wells, including anaerobic ones, without causing any harm to the water. If, after applying silver, you look at a drop of water from a well under a microscope, it is unlikely that you will be able to detect pathogenic microbes there, including anaerobic ones. This method is good for standing water tanks:

wells,
wells,
storage containers.

Many microorganisms also live in the salt water of the seas. At the same time, salt water is an unfavorable environment for pathogenic bacteria. Despite the fact that up to 5 million microorganisms live in a teaspoon of salty sea water, almost all of them are cyanobacteria and do not harm human health.

Natural water is precisely the environment where numerous microorganisms intensively reproduce, and therefore the microflora of water will never cease to be the object of close attention of man. How intensively they multiply depends on many factors. In natural water, mineral and organic substances are always dissolved in one or another amount, which serve as a kind of "food", thanks to which the entire microflora of water exists. In terms of quantity and quality, the composition of micro-inhabitants is very diverse. It is practically never possible to assert that this or that water, in this or that source, is pure.

artesian water

Spring or artesian waters are underground, but this does not mean at all that microorganisms are absent in them. They are sure to exist, and their composition depends on the nature of the soil, soil and the depth of this aquifer. The deeper - the poorer the microflora of water, but this does not mean that it is completely absent.

Most of the bacteria are found in ordinary wells, which are not deep enough to allow surface contaminants to seep into them. It is there that pathogenic microorganisms are most often found. And the higher the groundwater is, the richer and more abundant the microflora of the water. Almost all closed-type reservoirs are excessively saline, since salt has accumulated underground for many hundreds of years. Therefore, most often artesian water is filtered before drinking.

surface water

Open reservoirs, that is, surface waters - rivers, lakes, reservoirs, ponds, swamps, and so on - have a variable chemical composition, and therefore the composition of the microflora there is very diverse. This is because every drop of water is contaminated with both household and often industrial waste and the remains of rotting algae. Rain streams flow here, bringing a variety of microlife from the soil, and factory and factory productions get here.

Simultaneously with all kinds of mineral and organic pollution, water bodies also receive huge masses of microorganisms, including pathogenic ones. Even for technological purposes, water is used that meets GOST 2874-82 (in one milliliter of such water there should not be more than a hundred cells of bacteria, in a liter - no more than three cells of Escherichia coli.

pathogens

Such water, under a microscope, presents the researcher with a number of pathogens of intestinal infections, which remain virulent for quite a long time. For example, in ordinary tap water, the causative agent of dysentery is viable for up to twenty-seven days, typhoid fever - up to ninety-three days, cholera - up to twenty-eight. And in river water - three or four times longer! threatens with disease one hundred and eighty-three days!

The water is carefully monitored, and if necessary, even a quarantine is declared - if there is a threat of an outbreak of the disease. Even sub-zero temperatures do not kill most microorganisms. A frozen drop of water keeps quite viable bacteria of the typhoid group for several weeks, and this can be verified using a microscope.

Quantity

The number of microbes and their composition in open water directly depend on the chemical reactions taking place there. The microflora of drinking water greatly increases with the dense population of coastal areas. Over the years, it changes its composition, and there are many other reasons for changes in one direction or another. The cleanest reservoirs contain up to eighty percent of coccal bacteria among all microflora. The remaining twenty are mostly rod-shaped, non-spore-bearing bacteria.

Near industrial enterprises or large settlements in a cubic centimeter of river water, there are many hundreds of thousands and millions of bacteria. Where there is almost no civilization - in taiga and mountain rivers - water under a microscope shows only hundreds or thousands of bacteria in the same drop. In stagnant water, there are naturally many more microorganisms, especially near the banks, as well as in the upper layer of water and in the silt at the bottom. Silt is a nursery for bacteria, from which a kind of film is formed, due to which most of the processes of transformation of the substances of the entire reservoir occur and the microflora of natural waters is formed. After heavy rains and spring floods, the number of bacteria also increases in all water bodies.

"Blossoming" of the reservoir

The level of saprophytic microflora complements the sanitary characteristics of reservoirs - sources of water supply. Since pure water is relatively poor in nutrients, the amount of saprophytes in it depends on the content of easily digestible organic substances. The presence of saprophytes in water is an indicator of water quality. An increase in the amount of nutrients in water bodies causes the "bloom" of water due to the development of microscopic plants - phytoplankton. At the same time, the organoleptic properties of water deteriorate, tastes and odors appear, and anaerobic processes develop. All these phenomena are unfavorable in hygienic terms.

In the water of reservoirs there are also pathogenic microbes that cause gastrointestinal and other human diseases. Some of them can remain viable in water for a long time.

River silt is especially rich in microorganisms: in 1 g of dry river silt there are up to 2-3 billion microbial cells, and in 1 g of wet lake silt the number of microorganisms reaches 400 million. The largest number of microorganisms is observed in the surface layer of silt, where a kind of film of bacteria. It contains many sulfur bacteria and iron bacteria and plays an essential role in the transformations of substances in the reservoir. Sulfur bacteria oxidize the hydrogen sulfide formed in the sludge to sulfuric acid, thus preventing its penetration into the water. The lack of oxygen in the soil promotes the development of anaerobic bacteria, causing fermentation of plant residues with the formation of methane and hydrogen.

Sources of water supply for domestic needs and the needs of industrial enterprises, especially food, must be protected from pollution.

When water bodies are polluted with some types of industrial and waste water, specific pests of food production can also get into the water with them. When using water containing these microbes, yeast, bacteria and mold fungi are introduced into technological containers, which worsen the quality of food products. Therefore, for technological purposes, only water that meets the requirements of GOST 2874-82 can be used: 1 ml of undiluted water should not contain more than 100 bacterial cells; in 1 liter of water there should not be more than 3 cells of bacteria of the Escherichia coli group (coli index); if the titer should be at least 300.

We find them in various bodies of water - stagnant and flowing, shallow and deep, hot and icy, salty and fresh, clean and polluted, in lakes, swamps, seas and oceans. Coastal and bottom silts of reservoirs are also rich in microorganisms.

In seawater off the Svalbard islands, bacteria were found at a depth of 2,700 m. Oceanographic surveys of the Pacific Ocean off the coast of the Philippine Islands found bacteria at a depth of 10,462 m, in one of the deepest trenches in the World Ocean.

During the Dodo oceanographic expedition in 1964, microbiologist K. Zobell discovered a large number of microorganisms at various depths and in the bottom sediments of the Pacific Ocean (photo 33). When cultivating these organisms, conditions were created that prevail at a depth of more than 10,000 m - a temperature of 2.5 ° C and a pressure of 1000 atm. It turned out that at such a high pressure, bacteria multiplied tens and thousands of times more intensively than at atmospheric pressure.

Comparing the reaction of various bacteria to high pressure, Zobell found that terrestrial bacteria do not grow or die under a pressure of 600 atm, while marine bacteria taken from a depth of 6000 m feel normal under these conditions. The same researcher reported that thermophilic bacteria, which cease their growth at normal atmospheric pressure already at temperatures slightly above 85°C, are able to grow and multiply at a pressure of 1000 atm even at 104°C. This is considered to be the highest known temperature at which bacteria can grow.

It is known that the glow of the sea, often observed at night, is caused by microorganisms. These luminous creatures belong mainly to flagellated organisms; among them there is a genus named Noctiluca, which means "night firefly". In his book "Diary of research on natural history and geology", Charles Darwin wrote about the glow of the sea: "... the sea shone with flashes. The phenomenon was very similar to what one would expect if a large fish quickly moved liquid" * .

* (C. Darwin, A naturalist's journey around the world on the ship "Beagle", M., Geografgiz, 1955, p. 201. - Approx. ed.)

Unicellular green algae in the phytoplankton of the oceans account for 80% of all organic matter formed on our planet through photosynthesis. There are also microorganisms in sea waters that mineralize the organic matter of dying creatures and in this way return them to the cycle of nature. Green algae produce yellow pigments that are very similar in color to the water in some ponds, and therefore it is suggested that yellow substances * found in natural reservoirs may be waste products of algae.

* (Water-soluble humic substances (fulvic acids) of a complex chemical nature; found in soil and natural waters. - Approx. ed.)

Microorganisms also live in hot springs. Microscopic algae have been found in the water flowing from the baths of the Piestany resort (Western Slovakia), the temperature of which reaches 90°C. The hot springs of the Balkan Peninsula are inhabited by bacteria that can withstand temperatures of 83°C. When studying the photosynthetic activity of algae from the hot springs of the Yellowstone National Park (USA), it was found that the process of photosynthesis occurred at 75°C. Some bacteria were found in the spring, which had a water temperature of 91.5°C - only 2° below the boiling point recorded in the area. In the channel through which water flows from the source, the temperature reaches 88 ° C, but even here there are so many bacteria that they paint the walls of the channel pink. American microbiologists T. Brock and J. Darland reported on the results of studies of bacteria in 300 hot springs located in the USA, New Zealand and Iceland. They found that in moderately acidic waters, bacteria live at temperatures above 90 ° C, and in alkaline waters they can withstand even 100 ° C!

From reservoirs with a high salt content (Dead Sea, Great Salt Lake), bacteria were isolated that produce yellow and red pigments (some of them are associated with the color of fish living in salt water). Life in water with a high concentration of salts is impossible for most organisms. However, 30 species of organisms were found in the Great Salt Lake, mainly bacteria, as well as several species of blue-green and green algae, protozoa, two species of arthropods and two species of reptiles. Even more severe conditions in the Dead Sea. But even here, eight species of bacteria and two species of blue-green algae were found.

The record was set by microorganisms found in the small Antarctic lake Don Juan, whose waters are characterized by a high salt concentration and low temperature. Members of the American expedition who conducted research were surprised to note that the water in it does not freeze even at a temperature of - 24 ° C, which is explained by the high salt content - 13 times higher than in sea water. But even from this lake, bacteria and yeasts were isolated that adapted to such unfavorable environmental conditions.

Pathogenic bacteria Pseudomonas aeruginosa can grow even in distilled water. In the journal Science in 1971, a report was published by four microbiologists who analyzed 50 samples of distilled water. These bacteria were found in 20 of them. The water was taken from supplies intended for aerosol therapy at two children's hospitals. Bacteria multiplied intensively, and in 24 hours at a temperature of 25°C their number increased by 250 times!

According to one of the most common scientific theories, bacteria are called the oldest, quite possibly the first living organisms on Earth. Microbes inhabit even the most extreme places on the planet. For example, life does not require oxygen. The total mass of bacteria in the Earth's biosphere is approximately 350-550 billion tons.

The most optimal habitat for protozoa, which include anaerobic bacteria, is water. In different water bodies, the composition of bacteria can vary, depending on many factors:

environment temperature,
salt content,
standing water or running water
absence or presence of sunlight.

bacteria in the aquarium

Microorganisms living in an aquarium, in addition to the harm caused by some species, can have a positive effect. Useful from ammonia, which is in the waste products of its residents. While Nitrosomonas converts the ammonia in the aquarium into nitrite, the genus Nitrobacter converts nitrite into nitrate, purifying the aquarium's stagnant water (and completing the nitrogen cycle). Beneficial saprophyte bacteria do not spoil the water in the aquarium, but on the contrary, they purify it by feeding on rotting algae, food and waste products of fish. Disease-causing (pathogenic) microbes include bacteria such as:

Aeromonas - causes aeromonosis, in which the color of the fish fades, they stop eating. It is treated with the VUS-2 vaccine.

Pseudomonas are opportunistic bacteria. With insufficient nutrition of fish and disturbed biological balance of the environment, ulcers, mucus and death of fish are caused. Can be killed with biseptol.
Edwardsiella tarda - dangerous for goldfish by infection of the intestinal tractleading to death. It is possible to neutralize these microbes with the help of oxytetracycline and biseptol added to the aquarium water.
A gram-negative rod provokes furunculosis, that is, it forms ulcers in fish. Penetrates into the aquarium with parts of the soil and dirty water. When infected, the fish should be moved to a separate aquarium with a solution of chloramphenicol.

Bacteria in wells

Each drop of drinking water, when viewed under a microscope, contains countless different useful and. Complete elimination of them is impossible. Even if we allow the possibility of complete disinfection provided by reverse osmosis and boiling, microbes will again enter the water from the air, faucet, dishes and other places. That is why the criteria for the admissibility of drinking tap water in medical practice are not categorical, but exclude the presence of pathogenic microbes, that is, those that can contribute to the development of the disease.

Pathogenic bacteria are hazardous to human health. This list includes, in particular:

Sallmonella typhi, non-typhi (salmonella);
Shiqella;
Campylobacter coli, C. jejuni;
Vibrio cholerae (Vibrio cholerae) and others.

There are also viruses that live in water. The most contagious is the hepatitis A virus (causes Botkin's disease). About a million people around the world catch this virus every year. The virus infects the liver and spleen. It is removed from the water by reverse osmosis or by using a membrane filter.

Determination of microorganisms in drinking water

It is very difficult and costly to determine all microorganisms present in a sample of drinking water from a well. Therefore, in laboratory conditions, the presence of only the most easily detectable representatives of the microflora is determined, which may indicate the presence of others, more in the water. These include colimorphic microorganisms.

Colimorphic, rod-shaped, Gram-negative microbes enter drinking water and wells mainly with faecal effluents. These include the following names:

Escherichia,
Citrobacter,
enterobacter,
Klebsiella.

Fight against pathogenic bacteria

The easiest way to purify water is to boil it. This is the most affordable and widely used method of getting rid of. Another way is a chlorine tablet dissolved in water, but you need to take into account the amount of water, as well as the harmfulness of the substance.