Bacteria are the causative agents of which diseases? Human diseases caused by bacteria

There are five main kingdoms of living nature, representatives of which have been thoroughly studied over many centuries. It:

• Animals;
• plants;
• Mushrooms;
• Bacteria, or prokaryotes;
• Viruses.

If animals, plants and mushrooms have been known to people since the very days of the initial period, then the study of viruses and bacteria has been done relatively recently. Too small in size are these organisms, so that it is possible to study them with the naked eye. That is why they were so long hidden from the sharp sight of mankind.

It is known that they play not only a positive role. So we will try to understand the question of what bacteria are the causative agents of which diseases, and how these beings are structured and live.

Who are prokaryotes?

All living beings on our planet are united by a commonality in the structure - they consist of cells. True, part of all of one, the other part - multicellular. If we talk about multicellular animals, then everything is uniform. Each such organism has a formed nucleus in the cells. But when it comes to unicellular organisms, then there is no such unity, since they are divided into eukaryotes and prokaryotes.

Eukaryotes include all living things, the cells of which have a hereditary material fixed in the nucleus. To prokaryotes - such unicellular organisms, in which DNA is distributed freely, is not limited to a nuclear envelope, and consequently, does not have a nucleus as a whole. To these beings it is customary to refer:

• Blue-green algae;
• Cyanobacteria;
• Arhebacteria;
• Bacteria.

Initially, only such organisms lived on the planet. But gradually evolution has come to the appearance of eukaryotic multicellular organisms, inside which prokaryotic cells have remained. Then they, having united together and having concluded symbiotic relations, became an excellent, strong, environmentally stable organism, ready for self-reproduction and increase in numbers, evolution.

The proof of this theory is such non-nuclear cellular organelles of multicellular, like mitochondria and plastids (chloroplasts, chromoplasts, leukoplasts).

But, unfortunately, many of the prokaryotic cells are not as harmless to plants, animals and people as those that have remained inside them. They received the modern name of bacteria, or microbes, and began to live an independent life, causing a lot of trouble for highly organized beings.

Many diseases associated with bacteria and their vital functions are known. And not only in man emerging, but in representatives of all other realms of living nature.

A Brief History Overview

Bacteria have been around for more than 3.5 billion years. During this time nothing has changed in their structure. The only thing that has become new in their lives is their fame for a person.

How did the discovery of these organisms occur? Let's consider step by step.

1. Another ancient Greek scientist Aristotle said that there are invisible to the eye creatures that live in everything around, including man. They can cause illness.
2. 1546 - Italian physician Girolamo Fraco-strano suggested that human diseases are caused by the smallest organisms, microbes. However, he could not prove this and remained unheeded.
3. 1676 - Antonio van Leeuwenhoek studied the slice of a cork tree under a microscope invented by himself (the first microscope of its production was very large and resembled a collection of several disparate mirrors, it gave an increase of more than a hundred times). As a result, he managed to see the cells from which the tree bark consists. And also, looking at a drop of water, he examined a lot of the smallest organisms that lived in this drop. This was the bacteria, which he gave the name "animalkuli."
4. 1840 - the German physician Jacob Henle proposes an absolutely correct hypothesis about the effect of pathogenic microorganisms on humans, that is, that bacteria are pathogens.
5. 1862 - the French chemist Louis Pasteur, as a result of repeated experiments, proved the presence of microorganisms in all media of life, objects, organisms. Thus, he confirmed the Henle hypothesis, and it has already become a theory, called the "Microbial Theory of Diseases". For his work, the scientist was awarded the Nobel Prize.
6. 1877 - Robert Koch introduces a method of staining bacterial cultures.
7. 1884 - Hans Gram, the doctor. It is to him the merit of dividing these creatures into gram-positive and gram-negative ones, depending on the reaction to the form of the dye.
8. 1880 - Karg Ebert revealed the cause of the disease with typhoid fever - the action of a rod-shaped bacterium.
9. 1882 - Robert Koch identifies a tubercle bacillus.
10. 1897 - Japanese doctor Kie-si Shiga discovered the cause of dysentery
11. 1897 - Bernhard Bang established the fact that there are bacteria-pathogens of animal diseases that cause miscarriages.

Thus, the development of knowledge about the bacteria and diseases caused by them, was gaining rapid growth. And today more than 10 thousand different representatives of prokaryotes have been described. However, scientists predict that there are more than a million species in the world.

The science of prokaryotes

Bacteria as agents of infectious diseases have always been of interest to science, since knowledge about them allows solving many health problems not only for humans, but also for animals and plants. Therefore, several sciences have been formed that deal with the study of this issue.

1. Microbiology is a common science that studies all microscopic organisms, including bacteria.
2. Bacteriology is a science that deals with the study of microbes, bacteria, their diversity, lifestyle, distribution and influence on the world around them.
3. Sanitary microbiology - studies preventive measures to develop bacterial diseases in humans.
4. Veterinary microbiology - investigates bacteria-causative agents of infectious diseases in animals, methods of elimination, treatment, prevention of infection.
5. Medical microbiology - examines the effect of bacteria on the life of all living beings from the point of view of medicine.

In addition to bacterial cells there are also single-celled protozoa, pathogens in humans, animals and plants. For example, amoebas, malarial plasmodia, trypanosomes and so on. They are also objects of studying medical microbiology.

What are bacteria?

There are two bases for the classification of bacterial cells. The first is built on the principle of dividing microbes, various in form cells. Thus, according to this feature, there are:

• Kokki, or spherical, globular organisms. It also includes several varieties: diplococci, streptococci, staphylococci, micrococci, sarcin, tetracoccus. The dimensions of such representatives do not exceed 1 μm. This group includes most of those who are called "pathogens of human diseases."
• Sticks, or rod-shaped bacteria. Varieties in the shape of the ends of the cell: regular, pointed, clavate, vibrio, circumcised, rounded, chained. All these bacteria are pathogens. What diseases? Virtually all infectious, known to man today.
• Crimson organisms. They are subdivided into spirilla and spirochetes. Thin crimped spiraling structures, some of which are pathogenic microbes, and the other - representatives of the normal microflora of the intestine of animals and humans.
• Branching bacteria - basically resemble rod-shaped forms, but at the end they have branchings of varying degrees. These include bifidobacteria, which play a positive role in people's lives.

Another classification of bacterial cells is based on modern indicators: RNA in structure, biochemical and morphological properties, relation to staining and so on. On these grounds, all bacteria can be divided into 23 types, each of which includes several classes, genera and species.

It is also possible to classify microorganisms according to the method of nutrition, respiration type, occupied habitat and so on.

Use of bacteria by humans

People have used microorganisms since ancient times. On their part, these were, of course, not a purposeful application, but simply a profitable acquisition by nature. For example, alcoholic beverages were produced, fermentation processes took place.

With the passage of time and the discovery of the mechanisms of life of these tiny creatures, man has learned to apply them more fully to his needs. It is possible to single out several branches of the economy, with which biology is closely intertwined. Bacteria are used:

1. In the food industry: baking confectionery and bread, winemaking, lactic acid products and so on.
2. Chemical synthesis: bacteria produce amino acids, organic acids, proteins, vitamins, lipids, antibiotics, enzymes, pigments, nucleic acids, sugars and so on.
3. Medicine: drugs that restore the microflora of the internal environment of the body, antibiotics and so on.
4. Agriculture: preparations for plant growth and animal treatment, strains of bacteria that increase yields, milk yields and egg production, and so on.
5. Ecology: oil-producing microorganisms, processing organic and inorganic residues, purification of the environment.

However, in addition to the positive effects of using bacteria, people can not get rid of negative ones. After all, bacteria are the causative agents of which human diseases? The most complex, dangerous and sometimes deadly. Therefore, their role in nature and people's lives is dual.

Disease-causing microbes: general characteristics

To pathogens include such microbes that are capable of causing damage to tissues and internal systems of organs in humans and animals. In their external and internal structure they are no different from useful bacteria: a unicellular structure covered with a dense membrane (cell wall), outside is clothed in a mucous capsule, which protects from digestion inside the host and from drying out. The genetic material is distributed within the cell as a chain of DNA molecules. Under unfavorable conditions, they are able to form spores - to fall into a state of stupor, in which processes of vital activity cease before the renewal of favorable conditions.

Bacteria are the causative agents of which diseases of living beings? Those that are easily transmitted by airborne droplets, by direct contact or by contact with exposed mucous areas of the skin. And this means that pathogens can be called weapons of mass destruction. After all, they are capable of causing whole epidemics, pandemics, epizootics, epiphytotics and so on. That is, diseases that cover entire countries, affecting both plants (epiphytotics), and animals (epizootics), and humans (epidemics).

Unfortunately, not all species of such creatures have been fully studied by humans yet. Therefore, there is no guarantee that at any time there will be no infection, people unknown. This imposes even greater responsibility on microbiologists, medical researchers and virologists.

What diseases are caused by bacteria?

There are many such diseases. In this case, it is impossible to single out only some common ones. After all, bacteria can affect not only animals, but also plant tissues. Therefore, all the diseases that they cause, it is common to divide into several groups.

1. Anthroponous infections are those that are characteristic only of humans, and infection is possible strictly between them (pathogens of human diseases). Examples of diseases: typhus, cholera, smallpox, measles, dysentery, diphtheria and others.
2. Zoonotic diseases are infections that affect animals and which they carry in themselves, but in any way they can infect a person. For example, when bites of insects or other animals, when animals contact the skin and the respiratory tract of a person, the transmission of bacteria spores takes place. Diseases: sap, anthrax, plague, tularemia, rabies, foot and mouth disease.
3. Epiphytic infections are plant diseases caused by bacteria. These include rot, spots, tumors, burns, gummoses and other bacterial diseases.

Consider human diseases caused by bacteria. The ones that are the most common. It is they who brought in the past and present many troubles and troubles to people.

Human Bacteria

Human diseases caused by bacteria have always caused much harm and damage to human health. The most common and dangerous of them are the following:

1. Plague is a terrible word for residents of the Middle Ages and the Renaissance. This disease has claimed thousands of lives. Previously, getting sick with plague was tantamount to death, until they came up with a method of vaccination and a cure for this terrible infectious disease. Now this disease occurs in some tropical countries and is strictly zoonotic in nature.
2. Erysipelas is a disease of animals, mainly pigs, chickens, lambs, horses. Sent to a person. It is caused by pathogenic bacteria, whose names are Erysipelothrix insidiosa. The fight against the disease is simple, these pathogens are afraid of direct sunlight, high temperatures and alkalis. Currently, the disease is not too common. The emergence of foci depends on the conditions of animal maintenance.
3. Diphtheria. A dangerous disease of the upper respiratory tract, gives a strong complication in the heart. Today, it is rare, as vaccination is carried out at early stages of the development of the child.
4. Dysentery. This disease is caused by bacteria, the names of which are shigella (Shigella). The source of infection is sick people who are able to transmit the infection by domestic, aqueous or contact (through the mouth) way. Children are most susceptible to the disease. Dysentery can be treated several times, as the immunity to the disease is formed only temporary.
5. Tularemia - caused by the bacterium Francisella tularensis. Very tenacious, resistant to temperatures, environmental conditions, infection. The treatment is complex, not fully developed.
6. Tuberculosis - is caused by a stick of Koch. A complex disease that affects the lungs and other organs. Healing systems have been developed and widely practiced, but they still can not completely eradicate the disease.
7. Pertussis is an infection caused by the bacterium Bordetella pertussis. Characterized by the appearance of severe attacks of cough. Vaccination in early childhood.
8. Syphilis is a very common sexually transmitted infection. It is caused by the causative agent spirochete trypanosome. It affects the genitals, eyes, skin, CNS, bones and joints. Treatment with antibiotics, medicine is known.
9. Gonorrhea - as well as syphilis, a disease of the XXI century. Sexually transmitted infections, antibiotic treatment. It is caused by bacteria - gonococci.
10. Tetanus - is caused by a stick Clostridium tetani, which throws the strongest toxins into the human body. This leads to terrible convulsions and uncontrolled contractions of the musculature.

Of course, there are other bacteria and human diseases. But the listed are the most common and serious.

Animal microbes

The most common diseases of animals that are caused by bacteria include:

• botulism;
• tetanus;
• Pasteurellosis;
• Colibacillosis;
• Bubonic plague;
• glanders;
• Melioidosis;
• Yersiniosis;
• Vibriosis;
• Actinomycosis;
• anthrax;
• Foot and mouth disease.

They are all caused by certain bacteria. Diseases are mostly able to be transmitted to people, therefore they are extremely dangerous and serious. The main measures to prevent the spread of such diseases are keeping the animals clean, carefully caring for them, limiting contact with the sick.

Plant microbes

Among the harmful microbes, affecting the root systems and shoots of plants and causing serious damage to agriculture, the most common are the following representatives:

• Mycobacteriaceae;
• Pseudomonadaceae;
• Bacteriaceae.

Diseases of plants caused by bacteria cause rotting and death of the following parts of cultivated plants:

• Roots;
• Leaves;
• Stems;
• Fruits;
• Inflorescence;
• Root crops.

That is, the entire plant can be affected by the pathogen. Most often, agricultural plantations such as potatoes, cabbage, corn, wheat, onions, tomatoes, makhorka, grapes, various fruit and berry trees and other fruits, vegetables and grains suffer.

The main diseases include:

• Bacteriosis;
• cancer;
• Bacterial spotting;
• Rot;
• Ryabuha;
• Basal bacteriosis;
• Bacterial burn;
• Ring rot;
• Black leg;
• Gummosis;
• Striatal bacteriosis;
• Black bacteriosis and others.

Currently, botanists and agricultural microbiologists are actively working on finding the means of protecting plants from these misfortunes.