Bacterial infections

Bacterial infections include a huge group of diseases caused by microorganisms – bacteria. These are small unicellular microorganisms that have a strong cell wall to protect against the effects of aggressive environmental factors. Bacteria isolated in a separate realm – prokaryotes, since they do not have a nucleus, their genetic material is located in the cytoplasm of cells. These microorganisms are the most numerous and ancient of all living things, they live almost everywhere (water, air, soil, other organisms).

A few historical facts

For the first time see the microcosm, full of living things, in the XVII century. succeeded Dutch manufacturer Anthony van Leeuwenhoek, who was carried away by grinding glass first in the world built a microscope. Considering the water from the puddle, he saw that it was full of microorganisms, and gave them the name “microscopy.” The connection of microorganisms with diseases transmitted from one person to another was discovered by the French scientist Louis Pasteur in the 19th century. Before that, there was the idea that a patient with an infectious disease has a certain contagious beginning – “miasma”. Further, with the improvement of microscopic technology in the late nineteenth century, early XX century. Scientists managed to discover the causative agents of many infectious diseases (tuberculosis, typhoid fever, dysentery, cholera, plague). And although the pathogens were known, but mankind could effectively fight the bacteria, only after the discovery of antibiotic penicillin by the English bacteriologist Alexander Fleming.

Classification of bacteria

Given that the bacteria are a very large group of microorganisms, they are divided into several groups according to certain criteria.

By way of a food:

saprophytes – free-living bacteria that feed on non-living organic matter, not pathogenic (the only exception are Legionella – the microbes that live in the fluid of air conditioners, when ingested, cause pneumonia);

parasites – eat at the expense of others, this group includes all pathogenic bacteria, as well as the necessary microorganisms that live in “commonwealth” with man (normal intestinal microflora consists of beneficial bacteria that in the process of life synthesize the B vitamins needed by the human body) .

According to the shape of the cell:

cocci – globular bacteria. These include: meningococcus (meningitis), staphylococcus (the majority of pustular diseases), pneumococcus (pneumonia), streptococcus (tonsillitis, erysipelas, streptoderma).

rod-shaped bacteria – cell shape in the form of a straight or curved rod. The causative agents of the diseases are: E. coli (acute intestinal infections, inflammatory diseases of the internal organs), shigella (dysentery), mycobacterium tuberculosis, diphtheria bacillus (diphtheria), tetanus.

crimson bacteria – in shape resemble a corkscrew spiral: pale treponema – the causative agent of syphilis, leptospira – the disease of leptospirosis (it is interesting that the shape of the corkscrew helps spirochetes literally “get in” through the human skin and thus penetrate the body).

bacteria that change form – a special group of bacteria without a cell wall – are intracellular parasites: mycoplasmas (chronic diseases of the genitourinary organs that are difficult to treat).

flagellate forms – bacteria on the cell have flagella, actively move in the external environment, which allows them to increase the possibility of infection (cholera vibrio – causative agent of cholera).

Pathogenesis of bacterial infections

The most important in the development of diseases caused by a bacterial infection is the release of toxins (poisons) by bacteria that have an inflammatory effect, cause intoxication of the organism and damage internal organs:

endotoxins – is released after the death of the bacterium and the destruction of its cells (intestinal infections). The most dangerous is meningococcal endotoxin in meningococcal infections. In the event of the death of a significant number of bacteria, the released endotoxin can lead to the development of an infectious-toxic shock and lead to death.
 exotoxins – poisons released by living bacteria in the process of their vital activity (diphtheria).

Principles of diagnosis of bacterial infections

The main method for diagnosing bacterial infections is bacteriological research. In this case, the patient takes the material containing the bacteria, and is sown on special nutrient media. After the colonies grow on nutrient media (about 48 hours), the bacteria are identified. The huge advantage of this method is the ability to conduct a sensitivity study of the isolated bacterium to antibiotics, for the purpose of rational treatment. Also used are:

microscopic examination of the material – allows you to put an indicative diagnosis when detecting bacteria with a microscope.
     serological examination – the presence of antibodies in the blood to certain bacteria is determined, an increase in the antibody titer indicates the presence of bacteria in the body.

Principles of treatment of bacterial infections

Treatment of bacterial infections, like any other disease, is complex and includes:

etiotropic therapy – treatment aimed at eliminating the cause of the disease – bacteria. For this, an arsenal of antibiotics is used. At the moment there are several groups of antibiotics, but the most important is their separation into bactericidal antibiotics (kill bacteria) and bacteriostatic (suppress the growth and reproduction of bacterial cells). This is very important to know, especially in the case of meningococcal infection, the appointment of bactericidal antibiotics will lead to mass death of meningococci and the release of endotoxins into the blood.

pathogenetic therapy – is aimed at removing from the body of bacterial toxins that accumulate in the course of an infectious disease (detoxification). Also, treatment aimed at restoring damaged organs is carried out.

symptomatic therapy – is needed to alleviate the condition of a person with bacterial infection and reduce the severity of symptoms.

At the present time, thanks to antibiotics, it is possible to cure most bacterial infections, but it should be remembered that improper intake of antibiotics can lead to the development of resistance (insensitivity) in bacteria and even dependence on antibiotics.

local_offerevent_note April 17, 2018

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