Among the huge variety of microorganisms, you can meet both friends who provide the vital functions of our body, and the worst enemies. Such life forms are divided into bacteria, viruses, fungi and protozoa. Sometimes these microorganisms are combined with 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 organs cope with their functions.
Bacteria, their structure
Bacteria are the simplest unicellular organisms. They have small sizes (0.5-10 microns) and different shapes. The cell of these organisms consists of a membrane and a cytoplasm. The cell membrane plays a large role in the metabolism of the environment. The cytoplasmic membrane is tightly attached to the membrane and consists of proteins, lipids and enzymes. She 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. In bacteria, there is no formed nucleus. Instead, there is a nuclear substance that contains DNA and RNA.
Cell chemistry
The main component of a bacterial cell is water. It occupies 80% of the total mass of the microorganism. However, in disputes its content is much lower - about 20%. Many bacteria tolerate a decrease in the amount of water (drying) quite well. At the same time, metabolic processes slow down, and they cease to multiply. In addition, the composition of the cell includes proteins, carbohydrates, fats, as well as minerals and nucleic acids.
Bacteria movement
Bacterial cells make movements thanks to a special organ - flagella. These are thin threadlike formations, their number and location are diverse. Their thickness is approximately 0.01-0.03 microns. At the same time, several types are distinguished. If the flagellum is one and it is placed at the same pole, such bacteria are called monotrich. Microorganisms in which at one of the poles there is a bundle of flagella - monopolar lofotrich. Those bacteria in which beams are placed at the poles are called amphitrichs. But if the entire surface of the cell is covered with flagella, then these are peritrichi. Another way to move bacteria is to slip. It is believed that this is due to the fact that the cells contract in waves.
How microorganisms multiply. Spore formation
The method of reproduction in bacteria is quite simple. Its essence lies in the fact that the cell is divided into two, reaching a certain size. First, it lengthens, then a transverse septum appears, sets of cells diverge at the poles. If you create favorable conditions, then the division of bacteria can occur every 20 minutes. But most organisms die under the influence of the environment. To tolerate adverse conditions, bacteria can form spores. In this state, they are able to maintain life for thousands of years. Even in ancient mummies, bacterial spores were found. They are formed in several types: inside, in the middle or at the end of the cell.
Bacteria morphology
Depending on the form, bacteria are classified into the following types:
- Spherical. These bacteria are pathogens of various diseases. These include staphylococci (have the form of grapes), streptococci (form a long chain). Recent microorganisms cause inflammation and diseases such as tonsillitis, otitis media, pneumonia. Staphylococcal bacteria are pathogens of the digestive tract, purulent processes. The most dangerous representative is Staphylococcus aureus.
- Rod-shaped. This view has the shape of a cylinder. Often they form spores. Such microorganisms are called bacilli. Such bacteria are causative agents of anthrax.
- Spiral-shaped. They got their name because of the shape with curls. These include spirills, which are a fairly harmless organism. Spirochetes look like a thin twisted thread. It is known that these bacteria are causative agents of syphilis.
- Vibrios. Representatives of this category have a slightly curved shape. They have a characteristic feature: such pathogen bacteria are stable in an alkaline environment. Cause a disease like cholera.
- Mycoplasmas. A feature of this type is the absence of a cell membrane. Outside the host’s body, they are not capable of life. The question of which pathogens of the disease are mycoplasma bacteria has a rather simple answer: basically they provoke the appearance of diseases in cattle or plants.
Cholera
One of the most dangerous infections is cholera. It affects the digestive system and causes severe intoxication of the body. What bacteria are the causative agents of cholera? These microorganisms were discovered by
Robert Koch. Vibrio cholerae has the shape of a slightly curved stick. A distinctive feature of these bacteria is their high mobility. Vibrio cholerae enter the small intestine and are fixed there. There they produce protein toxins, as a result of which the water-salt balance is disturbed, the body is greatly dehydrated. Bacteria are resistant to alkaline conditions, but acid is harmful to them. In addition, despite the fact that they are well tolerated by low temperatures, boiling kills the cholera vibrio instantly. Infection is possible through 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 that can lead to death. Children are especially difficult to tolerate pneumonia. It can be caused not only by viruses. The answer to the question of which bacteria are the causative agents of the disease is known: these are pneumococci (up to 90%). Also provoke the appearance of inflammatory processes of staphylococcus (about 5%) and streptococcus. 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 be provoked by group B streptococci, Staphylococcus aureus. Often such a disease occurs as a result of the transferred flu. Bacterial pneumonia is treated with antibacterial drugs. In especially severe cases, such as, for example, the young age of the patient, hospitalization is necessary. How prevention methods use vaccination, promotion of breastfeeding up to six months (exclusively breast milk). It is also important to monitor personal hygiene and indoor air cleaning.
Chlamydia
Only recently has the fact been established that chlamydia refers to bacteria.
What disease pathogens are bacteria of this species? First of all, they can cause conjunctivitis of the eye,
urogenital infection, trachoma. A special type of chlamydia causes pneumonia and acute respiratory infections. Once in the host cells, microorganisms begin to divide. The entire cycle takes approximately 72 hours, as a result of which the affected cell is destroyed. A particular danger is such an infection for women. It plays a significant role in the formation of infertility. If there is an infection with chlamydia of the fetus, 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 an infection is asymptomatic.
The causative agents of scabies and other diseases
Quite often, amateurs ask themselves whether the bacteria are the causative agents of scabies. This, of course, is not so. A disease such as scabies provokes a tick, which when it enters the skin begins to multiply intensively, causing itching. But the complication of this disease - pyoderma, that is, purulent lesion of the skin - can cause bacteria of the cocci group. As a treatment, special ointments are used, as well as disinfection of clothes and linen.
The question of which bacteria are the causative agent of hepatitis is also relevant. Basically, hepatitis is the common name for inflammatory liver diseases. Mostly viruses cause them. However, there is bacterial hepatitis (with leptospirosis or syphilis). Leptospira, treponema - these bacteria are causative agents of hepatitis.
Another serious illness is malaria. The disease is transmitted to humans by insect bites (malaria mosquitoes). It is accompanied by fever, an increase in the size of the liver (possibly the spleen), and high fever. If treatment is not started on time, then a fatal outcome is possible. The causative agents are bacteria of the plasmodium genus malaria. To date, 4 species of such microorganisms are known. The most dangerous one that can cause tropical malaria. As you can see, bacteria are pathogens that have serious complications and require medical attention.