Which bacteria are pathogens? Bacteria and humans

Among a huge number of microorganisms can be found as friends who provide the vital functions of our body, and the worst enemies. These forms of life are divided into bacteria, viruses, fungi and protozoa. Sometimes these microorganisms are united by the word "microbes". Bacteria are the causative agents of many diseases, some species pose a serious danger to human life. However, those organisms that live in the human body, on the contrary, help the bodies cope with their functions.

Bacteria, their structure

Bacteria are called the simplest unicellular organisms. They have small dimensions (0.5-10 μm) and different shapes. The cell of these organisms consists of a membrane and a cytoplasm. The cell membrane plays a big role in the metabolism with the environment. The cytoplasmic membrane is tightly attached to the membrane and consists of proteins, lipids and enzymes. It is responsible for the processes of excretion and entry into the cell of substances, being an osmotic barrier. The main component of the cytoplasm is protein. It is here that the energy processes that ensure the vital activity of the cell occur. There is no nucleus in the bacterium. Instead, there is a nuclear substance that contains DNA and RNA.

Chemical composition of the cell

The main constituent of a bacterial cell is water. It occupies 80% of the total mass of the microorganism. However, in disputes, its content is much less - about 20%. Many bacteria fairly well tolerate a decrease in the amount of water (drying). At the same time metabolic processes slow down, and they stop multiplying. In addition, the cell contains proteins, carbohydrates, fats, as well as minerals and nucleic acids.

Movement of bacteria

Bacterial cells move through a special organ - flagella. These are thin threadlike formations, their number and location are varied. Their thickness is approximately 0.01-0.03 μm. In this case, several types are distinguished. If the flagella is one and it is placed on one pole - such bacteria are called monotorichs. Microorganisms, which have a bundle of flagella at one of the poles - monopolar lofotrihi. Those bacteria that have beams placed on poles are called amphitrichs. But if the whole cell surface is covered with flagella, then it is peritrichi. Another way to move bacteria is sliding. It is assumed that this is due to the fact that the cells are undulating in wave form.

How do microorganisms multiply. Spore formation

The way of reproduction in bacteria is fairly simple. The essence of it is that the cell is divided into two, reaching a certain size. First it lengthens, then a transverse septum arises, the sets of cells diverge at the poles. If favorable conditions are created, the division of bacteria can occur every 20 minutes. But most organisms die under the influence of the environment. To transfer adverse conditions, bacteria are able to form spores. In this state they are capable of preserving vital activity for thousands of years. Even in ancient mummies, spores of bacteria were found. They are formed in several types: inside, in the middle or at the end of the cell.

Morphology of bacteria

Depending on the form, bacteria are classified into the following types:

1. Spherical. These bacteria are the causative agents of various diseases. These include staphylococci (in the form of grapes), streptococci (form a long chain). The latter microorganisms are the cause of inflammatory processes and diseases such as tonsillitis, otitis media, pneumonia. Staphylococcal bacteria are pathogens of the food tract, purulent processes. The most dangerous representative is Staphylococcus aureus.
2. Bacilliform. This view is in the form of a cylinder. Often they form spores. Such microorganisms are called bacilli. Such bacteria are the causative agents of anthrax.
3. Spiral-shaped. They got their name because of the shape with the curls. They include the spirilla, which is a fairly harmless organism. Spirochetes look like a thin twisted strand. It is known that these bacteria are the causative agents of syphilis.
4. Vibrio. Representatives of this category have a slightly curved shape. They have a characteristic feature: such bacteria-pathogens are stable in alkaline environment. Cause a disease like cholera.
5. Mycoplasmas. A feature of this type is the absence of a cell membrane. Outside the body of the host, they are not capable of life. The question of which pathogens are mycoplasma bacteria has a fairly simple answer: they mainly provoke the appearance of diseases in cattle or plants.

Cholera

One of the most dangerous infections is cholera. It affects the digestive organs and causes severe intoxication of the body. Which bacteria are the causative agents of cholera? These microorganisms were discovered by Robert Koch. The cholera vibrio has the shape of a slightly curved stalk. A distinctive feature of these bacteria is greater mobility. Cholera vibrios enter the small intestine and are fixed there. There they produce protein toxins, as a result of which the water-salt balance is violated, the body is highly dehydrated. Bacteria are characterized by their resistance to alkaline environment, but the acid for them is fatal. In addition, despite the fact that low temperatures are transferred by them well, boiling kills the cholera vibrio instantly. Infection is possible by contact with a sick person, through food or water. The incubation period is 5 days.

Pneumonia

Inflammation of the lungs is a rather serious disease, which can lead to death. Particularly hard for children are pneumonia. It can cause not only viruses. The answer to the question of which bacteria are the causative agents of the disease is known: pneumococci (up to 90%). Also provoke the appearance of inflammatory processes of staphylococcus (about 5%) and streptococci. Bacteria are located in the nasal passages and throat.

The most common symptoms of pneumonia are high fever, shortness of breath, general intoxication of the body. One of the most dangerous is intrauterine pneumonia. It can provoke group B Streptococcus, Staphylococcus aureus. Often such a disease occurs as a result of a transferred flu. Bacterial pneumonia is treated with antibacterial drugs. In particularly severe cases, such as the patient's small age, hospitalization is necessary. How the methods of prevention use vaccination, the promotion of breastfeeding for up to six months (exclusively mother's milk). It is also important to monitor personal hygiene and clean indoor air.

Chlamydia

Only recently has been established the fact that chlamydia belong to bacteria. What kind of disease is caused by bacteria of this species? First of all, they can cause conjunctivitis of the eye, urogenital infection, trachoma. A special kind of chlamydia causes pneumonia and acute respiratory diseases. Once in the host cells, the microorganisms begin to divide. The entire cycle takes approximately 72 hours, as a result of which the affected cell is destroyed. Such an infection is especially dangerous for women. It plays a significant role in the formation of infertility. If infection of the fetus with chlamydia occurs, then the probability of his death is high. That is why it is important to undergo a study before planning for pregnancy, since often such infection is asymptomatic.

Scabies and other diseases

Quite often dilettantes are wondering whether bacteria are the causative agents of scabies. This, of course, is not so. Such a disease, like scabies, provokes a tick, which when it gets on the skin begins to multiply intensively, thereby causing itching. But the complication of this disease - pyoderma, that is, a purulent lesion of the skin - can cause bacteria in the coccus group. As a treatment, special ointments are used, as well as disinfecting clothes and linen.

The question of which bacteria are the causative agent of hepatitis is also relevant. In general, hepatitis is the common name for inflammatory liver diseases. They are mainly caused by viruses. However, there is also bacterial hepatitis (with leptospirosis or syphilis). Leptospira, treponema - these bacteria are the causative agents of hepatitis.

Another serious disease is malaria. The disease is transmitted to a person with insect bites (malarial mosquitoes). It is accompanied by a fever, an increase in the size of the liver (possibly a spleen), high fever. If you do not start treatment on time, then a lethal outcome is possible. Pathogens are bacteria of malaria of the genus Plasmodium. To date, there are 4 types of such microorganisms. The most dangerous thing is that it can cause tropical malaria. As you can see, bacteria are the causative agents of diseases that have serious complications and require medical care.