All unicellular organisms and some multicellular ones (fungi) are combined into the concept of microbes or microorganisms. Pathogenic microorganisms, penetrating inside a living being, cause the development of an infectious disease. The body reacts with various symptoms, the nature of which allows us to determine the type of infectious agent and the localization of the pathological process. Microbes are divided into several types, the main ones being viruses and bacteria.
Various microbes can be found in soil, water, air, and the body of animals or humans. Microbes receive all the substances necessary for their life through the membrane of the host cells, since they do not have digestive organs. Microbes reproduce by budding or fission. This process is facilitated by an ambient temperature of about 37-40 C°.
Viruses are even smaller in size than other microbes. Therefore, representatives of this species cannot be seen under a conventional microscope - they can only be studied under an electron microscope. Their sizes can range from 8 to 250 nm. Unlike bacteria, they are able to pass through the pores of filters, which is why they are called filterable.
When a viral agent penetrates the cells of living organisms, it forces them to synthesize viral components. The cell is damaged. Such infectious agents can destroy the affected cell or exist in it for a long period of time (in chronic infectious diseases). There are no visible disturbances in such a carrier cell. Antibiotics have no effect on these pathogens.
Interesting facts:
- Viruses cannot independently produce protein - a genetic set of information.
- Viruses are the most numerous bioform on planet Earth.
- About 33% of the human genome is virus-like.
- It is possible to grow this form in the laboratory using cultures from living tissues.
- Viruses cannot survive long time outside the host's body (just a few minutes).
Features of bacterial microorganisms
The difference between microorganisms, first of all, is that bacteria are single-celled microorganisms with many functional abilities. They have a shell and a primitive core.
A certain number of bacteria can cause various infectious diseases. This property is called pathogenicity. Most bacterial organisms can be cultivated on artificially prepared nutrient media. Bacteria reproduce by division (the whole process takes 20-30 minutes). These microorganisms can be eliminated with antibacterial drugs - antibiotics.
There are bacteria that are not pathogenic. Some of them, on the contrary, help our body - bifidobacteria, lactobacilli. They are necessary elements for the normal functioning of human organs and systems.
What are the differences between different microbes?
So, let's summarize. The difference between viruses and bacteria is the following points:
- Some microorganisms have a cellular structure, while others have a noncellular structure.
- Viruses are several times smaller in size than bacteria and other microbes.
- The virus penetrates the cell and destroys it from the inside, and the bacteria from the outside.
- Bacteria reproduce on their own, and viruses use the cells of a living organism to do this.
- Viral pathogens are unable to maintain their vital activity outside a living organism, and bacteria can form spores (a protective temporary form).
- Bacterial microorganisms can be both beneficial and pathogenic, and viruses necessarily cause the development of pathology.
- Differences in the treatment of viral and bacterial infections.
- The difference in methods and materials for laboratory cultivation of pathogens of these types.
These are microscopic organisms that can cause disease in humans, animals or plants. Although bacteria and viruses may have some general characteristics, they are also very different. Bacteria are usually much larger than viruses and can be viewed with a regular microscope. Viruses are about 1,000 times smaller than bacteria and are only visible under an electron microscope. Bacteria are single-celled organisms that reproduce independently of other organisms. Viruses need living help to reproduce.
Where do they meet?
Bacteria: Bacteria live almost anywhere, including in/on other organisms and on inorganic surfaces. Some bacteria are thought to be able to survive in extremely harsh environments, such as hydrothermal vents and the stomachs of animals or humans.
Viruses: Like bacteria, viruses can be found in almost any environment. They are capable of infecting animals and plants, as well as bacteria and. Viruses that infect extremophiles such as archaea have genetic adaptations that allow them to withstand harsh environmental conditions. Viruses can survive (from a few seconds to several years) on surfaces or objects that we use every day.
Bacterial and viral structure
Bacteria: Bacteria are prokaryotic cells that show all the characteristics of living organisms. Bacterial cells contain DNA, which is immersed in and surrounded by. These organelles perform vital important functions, allowing bacteria to obtain energy from the environment and reproduce.
Viruses: Viruses are not considered cells, but exist as nucleic acid particles (DNA or RNA) enclosed in a protein shell. Also known as virions, viral particles exist somewhere between living and nonliving organisms. Although they contain genetic material, they do not have the cell wall or organelles needed to produce and reproduce energy. Viruses rely solely on the host cell to replicate.
Size and shape
Bacteria: Bacteria can occur in a variety of shapes and sizes. Common bacterial cell shapes include cocci (spherical), bacilli (rod-shaped), spiral, and vibrio. Bacteria typically range in size from 200 to 1000 nanometers. The largest bacterial cells are visible to the naked eye. The world's largest bacteria are: Thiomargarita namibiensis, reaching up to 750,000 nanometers (0.75 millimeters) in diameter.
Viruses: The size and shape of viruses is determined by the amount of nucleic acid and proteins they contain. Viruses typically have spherical (polygonal), rod-shaped, or helical capsids. Some viruses, such as , have complex forms that involve the addition of a protein attached to the capsid, with tail fibers extending from the tail. Viruses are much smaller than bacteria. They typically range in size from 20 to 400 nm in diameter. The largest known viruses, pandoraviruses, are about 1000 nanometers in diameter.
How are they reproduced?
Bacteria: Bacteria usually reproduce through a process known as . In this process, one cell replicates and divides into two identical ones. Under the right conditions, bacteria can experience exponential growth.
Viruses: Unlike bacteria, viruses can only replicate with the help of a host cell. Because viruses do not have the organelles necessary to reproduce viral components, they must use host cell organelles to replicate. During viral replication, a virus introduces its genetic material (DNA or RNA) into a cell. Viruses replicate and contain instructions for creating viral components. Once the components are assembled and the newly formed viruses mature, they rupture the cell and move on to infect other cells.
Diseases caused by bacteria and viruses
Bacteria: While most bacteria are harmless and some are even beneficial to humans, other bacteria can cause disease. Pathogenic bacteria that cause disease produce toxins that destroy body cells. They can cause food poisoning and other serious illnesses, including meningitis, pneumonia and tuberculosis. Bacterial infections can be treated with antibiotics, which are very effective at killing bacteria.
However, due to the overuse of antibiotics, bacteria have become resistant to them. Some of them even became known as superbugs because they became resistant to many modern antibiotics. Vaccines are also useful in preventing the spread of bacterial diseases. The best way Protecting yourself from bacteria and other germs is by washing your hands correctly and often.
Viruses: viruses are those that cause a number of diseases, including chickenpox, influenza, rabies, Ebola, Zika disease and HIV/AIDS. Viruses are capable of causing persistent infections in which they remain dormant and can be reactivated at a later time.
Some viruses cause changes in host cells that lead to the development of cancer. These viruses are known to cause cancers such as liver cancer, cervical cancer and Burkitt's lymphoma. Antibiotics do not work against viruses. Treatment for viral infections usually involves medications that treat the symptoms of the infection rather than the virus itself. As a rule, the immune system fights viruses on its own. Vaccines can also be used to prevent certain viral infections.
Due to insufficiently developed immunity, our children often get sick. Parents begin to worry about their child, even if he has caught a common cold. After all, it can be a symptom not only of a common cold, but also be a manifestation of a viral or bacterial infection. How to distinguish a viral infection from a bacterial one in this case? What treatment approach is required based on this? Let's try to figure it out.
Viral and bacterial infection has its own characteristic symptoms, which help make a preliminary diagnosis with almost 100% accuracy. The child’s body can cope with viruses on its own, but bacterial infections are no joke; microorganisms multiply quickly and often cannot be avoided without antibiotics.
Single-celled bacteria are full-fledged microorganisms that can live independently. They live around us and in ourselves. When a person’s immunity weakens, they begin to attack his body, releasing toxins. The same happens if the pathogenic microorganism finds itself in favorable living conditions. Characteristic symptoms appear, which make it possible to understand that a person is infected with any bacteria:
There are many types of bacteria, they affect certain systems and provoke characteristic symptoms. These manifestations are only local or affect the entire body as a whole if the damage is severe.
Diagnosis includes not only recognition of symptoms, it is also carried out in order to establish the type of pathogen, this requires testing. They help make the correct diagnosis on the basis of which treatment is carried out. We expect success; the child will recover with minimal health risks, without complications or side effects.
How is a virus different from a bacteria? The virus does not have a cell; the material is located in a protein shell. It is smaller than a bacterium and to live it needs a carrier, which it kills in the process of its life. Therefore, symptoms of infection appear. The difference between a viral infection and a bacterial one is that viruses rarely affect only one area of the body; their manifestations are noticeable throughout the body. The course of viral infection in adults and children is the same, the only difference is in the severity of symptoms.
The following symptoms will help you understand that the child is infected with viruses:
Important! Don’t panic if your child’s cough persists for a long time after recovery. This is explained by the very sensitive mucous membrane of the throat, which takes longer to recover than other systems and organs. At the same time, you cannot stuff your child with antibiotics, which will still be powerless, since their effect is directed only at bacteria. Rinsing will help, which will remove unpleasant residual effects.
If the virus manifests itself with the symptoms described above, then treatment is symptomatic. It is also necessary to strengthen the child’s body’s defenses.
Treatment of bacterial diseases
A bacterial infection should only be treated by a highly qualified specialist. If symptoms appear, you must immediately visit your doctor or call ambulance. Only after the tests can treatment be prescribed, which includes:
- Taking antibiotics. Medicines of local or general action are prescribed; they are able to neutralize the activity of microorganisms.
- Taking symptomatic medications that will help alleviate the child’s condition.
- Folk remedies used to strengthen the body. They are taken with the permission of a doctor.
- Taking medications that restore beneficial intestinal microflora.
Immediately after the start of treatment, the child no longer poses a threat to others. This does not mean that they should be taken to prevent complications or stop the spread of infection among family members. If you start taking antiviral drugs very early, you can destroy beneficial microflora and allow bacteria to multiply even more.
Antiviral treatment
Symptoms of a viral infection go away on their own. Treatment is carried out to eliminate the manifestations of viruses that cause discomfort. The actions of the doctor and parents are as follows:
It is worth knowing that vaccinations only protect against certain viral infections. Bacterial diseases will not harm only in case of strong immunity. They are very contagious, so if a relative or friend is sick, it is better to limit their contact with the child.
There is no need to say that most infectious diseases are extremely severe. Moreover, viral infections are the most difficult to treat. And this despite the fact that the arsenal of antimicrobial agents is being replenished with more and more new agents. But, despite the achievements of modern pharmacology, true antiviral drugs have not yet been obtained. The difficulties lie in the structural features of viral particles.
These representatives of the vast and diverse kingdom of microorganisms are often mistakenly confused with each other. Meanwhile, bacteria and viruses are fundamentally different from each other. And in the same way, bacterial and viral infections differ from each other, as well as the principles of treating these infections. Although in fairness it is worth noting that at the dawn of the development of microbiology, when the “guilt” of microorganisms in the occurrence of many diseases was proven, all these microorganisms were called viruses. Literally translated from Latin, virus means I. Then, as scientific research progressed, bacteria and viruses were isolated as separate independent forms of microorganisms.
The main feature that distinguishes bacteria from viruses is their cellular structure. Bacteria are essentially single-celled organisms, while viruses have a non-cellular structure. Let us recall that a cell has a cell membrane with cytoplasm (the main substance), a nucleus and organelles located inside - specific intracellular structures that perform various functions in the synthesis, storage and release of certain substances. The nucleus contains DNA (deoxyribonucleic acid) in the form of paired spirally twisted strands (chromosomes), in which genetic information is encoded. Based on DNA, RNA (ribonucleic acid) is synthesized, which, in turn, serves as a kind of matrix for the formation of protein. Thus, with the help of nucleic acids, DNA and RNA, hereditary information is transmitted and protein compounds are synthesized. And these compounds are strictly specific to each type of plant or animal.
True, some single-celled organisms, the most ancient in evolutionary terms, may not have a nucleus, the function of which is performed by a nucleus-like structure - the nucleoid. Such non-nucleated unicellular organisms are called prokaryota. It has been established that many types of bacteria are prokaryotes. And some bacteria can exist without a membrane - the so-called. L-shape. In general, bacteria are represented by many types, between which there are transitional forms. By appearance There are bacteria-rods (or bacilli), curved (vibrios), spherical (cocci). Clusters of cocci may look like a chain (streptococcus) or a bunch of grapes (staphylococcus). Bacteria grow well on carbohydrate and protein nutrient media in vitro (in vitro). And with the correct method of seeding and fixation with certain dyes, they are clearly visible under a microscope.
Viruses
They are not cells, and unlike bacteria, their structure is quite primitive. Although, perhaps, this primitiveness determines virulence - the ability of viruses to penetrate tissue cells and cause pathological changes in them. And the size of the virus is negligible - hundreds of times smaller than bacteria. Therefore, it can only be seen using an electron microscope. Structurally, the virus is 1 or 2 molecules of DNA or RNA. On this basis, viruses are divided into DNA-containing and RNA-containing. As can be seen from this, a viral particle (virion) can easily do without DNA. A DNA or RNA molecule is surrounded by a capsid, a protein shell. This is the entire structure of the virion.
When approaching a cell, viruses attach to its shell, destroying it. Then, through the resulting envelope defect, the virion injects a strand of DNA or RNA into the cell cytoplasm. That's all. After this, viral DNA begins to reproduce many times inside the cell. And each new viral DNA is, in fact, new virus. After all, the protein inside the cell is synthesized not by the cell, but by the virus. When a cell dies, many virions emerge from it. Each of them, in turn, searches for a host cell. And so on, in geometric progression.
Viruses are present everywhere and everywhere, in places with any climate. There is not a single species of plant or animal that is not susceptible to their invasion. It is believed that viruses were the very first life forms. And if life on Earth ends, then the very last elements of life will also be viruses. It should be noted that each type of virus infects only a certain type of cell. This property is called tropism. For example, encephalitis viruses are tropic to brain tissue, HIV is tropic to the cells of the human immune system, and the hepatitis virus is tropic to liver cells.
Basic principles of treatment of bacterial and viral infections
All microorganisms, bacteria, and viruses are prone to mutation - changing their structure and genetic properties under the influence of external factors, which can be heat, cold, humidity, chemicals, ionizing radiation. Mutations are also caused by antimicrobial drugs. In this case, the mutated microbe becomes immune to the action of antimicrobial drugs. It is this factor that underlies resistance - the resistance of bacteria to the action of antibiotics.
The euphoria that took place several decades ago after penicillin was obtained from mold has long since subsided. And penicillin itself has long retired, having passed the baton in the fight against infection to other, younger and stronger antibiotics. The effect of antibiotics on bacterial cells can be different. Some drugs destroy the bacterial membrane, others inhibit the synthesis of microbial DNA and RNA, and others uncouple the course of complex enzymatic reactions in the bacterial cell. In this regard, antibiotics can have a bactericidal (destroy bacteria) or bacteriostatic (inhibit their growth and suppress reproduction) effect. Of course, the bactericidal effect is more effective than the bacteriostatic one.
What about viruses? On them, as on non-cellular structures, Antibiotics don't work at all!
Then why are antibiotics prescribed for ARVI?
Maybe these are illiterate doctors?
No, the point here is not at all about the professionalism of doctors. The bottom line is that almost any viral infection depletes and suppresses the immune system. As a result, the body becomes susceptible not only to bacteria, but also to viruses. Antibiotics are prescribed as preventive measure against bacterial infection, which often occurs as a complication of ARVI.
It is noteworthy that viruses mutate much faster than bacteria. This may be due to the fact that there are no true antiviral drugs that can destroy viruses.
But what about Interferon, Acyclovir, Remantadine, and other antiviral drugs? Many of these drugs activate the immune system, and thereby prevent the intracellular penetration of the virion and contribute to its destruction. But a virus that has penetrated a cell is invincible. This largely determines the persistence (hidden asymptomatic course) of many viral infections.
An example is herpes, or more precisely, one of its types, herpes labialis - labial herpes. The fact is that external manifestations in the form of bubbles on the lips are just the tip of the iceberg. In fact, the herpes virus (a distant relative of the smallpox virus) is located in the brain tissue, and penetrates the mucous membrane of the lips through the nerve endings in the presence of provoking factors - mainly hypothermia. The above-mentioned Acyclovir is able to eliminate only the external manifestations of herpes. But the virus itself, once “buried” in the brain tissue, remains there until the end of a person’s life. A similar mechanism is observed in some viral hepatitis and HIV. This explains the difficulties in obtaining medications for the full treatment of these diseases.
But there must be a cure; it cannot be that viral diseases are invincible. After all, humanity was able to overcome the threat of the Middle Ages - smallpox.
Without a doubt, such a cure will be obtained. More precisely, it already exists. His name is human immunity.
Only our immune system can curb the virus. According to clinical observations, the severity of HIV infection has noticeably decreased over 30 years. And if this continues, then in a few decades the frequency of transition of HIV infection to AIDS and subsequent mortality will be high, but not 100%. And then this infection will probably be something like an ordinary, quickly passing disease. But then, most likely, a new one will appear dangerous virus, like today's Ebola virus. After all, the struggle between Man and the Virus, as between the macrocosm and the microcosm, will continue as long as Life exists.
Taras Anatolievich Nevelichuk
We know from childhood that when we come home, we should definitely wash our hands, as there are a lot of bacteria there. Then, having matured a little, we often hear from our parents about the dangers of viral infections. On TV we are told about the threat of bacterial weapons. It seems that viruses and bacteria are the most terrible and omnipresent enemies of humanity. But what is the difference between a virus and a bacteria?
In fact, viruses and bacteria can live in conditions that are unacceptable for the existence of any other living organism. However, not only harm comes from them. Scientists have obtained viruses that can destroy cancer cells in humans. Bacteria help prevent our planet from turning into one big landfill by recycling household waste.
Virus- this is the most primitive form of life . Viruses do not have a cellular structure and, thus, cause a lot of controversy regarding their relationship to living or non-living organisms (see).
Bacteria- These are single-celled organisms. The structure of this cell is more primitive than the cells of animals or plants, and, especially, humans. However, they can already be confidently classified as living.
Size
The size of the bacterium, on average, ranges from 0.0005mm to 0.003mm. While the size of a regular virus does not exceed 0.0003 mm. However, both bacteria and viruses have their own “giants” and “dwarfs”. The largest viruses have a size of about 0.00035 mm, while the smallest bacteria are no more than 0.00015 mm. Among bacteria there are also “giants” that are clearly visible to the naked human eye. Thus, the Thiomargarita bacterium, which lives on the seabed, has a size of 0.75 mm.
Structure
The structure of a primitive virus is a molecule, either DNA or RNA, surrounded by protein molecules that create an envelope. More complex viruses may have a second, outer shell and even contain enzymes.
Structure of viruses
Bacteria, although primitive, are still real cells. And, although they do not have a nucleus as such, DNA in the form of a coil is located directly in the cytoplasm, there is a cell membrane with capsules, flagella and microvilli, and RNA is present in the cell.
Structure of a bacterium Metabolism
Since bacteria are cells, they are characterized by their own metabolism. Viruses have very few enzymes and do not have metabolism
Reproduction
The virus invades only those cells where it can enter using cellular receptors. There it breaks down into nucleic acid and protein shells. These membranes are attached to the cell membrane. From this moment on, all processes in the cell are controlled by the genetic information contained in the NK of the virus. The cell itself begins to synthesize viral proteins. Then new viruses are formed from the newly formed nucleic acids and proteins, and the cell is destroyed.
Bacteria, like all cells, reproduce by division. If a bacterium is disbanded piece by piece, as happens with viruses, then it will no longer be able to recover.
Conclusions website
- Viruses are precellular living organisms, while bacteria are single-celled.
- Viruses cannot reproduce outside living cells. Bacteria reproduce independently by cell division.
- Viruses have only one type of nucleic acid, while bacteria contain DNA, RNA, ribosomes and a cell membrane.
