HealthMedicine

Gram-positive and Gram-negative bacteria

The world of bacteria is surprisingly diverse and very rich. They are found everywhere: in the air, the soil, on the skin of a person, on its mucous membranes. Under certain circumstances, bacteria become dangerous to humans, causing serious illness. Some of them can be easily treated with antibiotics or even ordinary antiseptics, others are much more difficult to get rid of. Therefore, when making a diagnosis, as well as when prescribing treatment, Gram-positive and Gram-negative bacteria are isolated. This method of dividing microorganisms was proposed in the XIX century, but is still used.

The world of bacteria

The kingdom of microorganisms is so diverse and complex that even modern science has not yet fully studied it. There are bacteria that survive at high temperatures and do not die even with prolonged boiling, while others die at the slightest change in temperature or composition of the external environment, for example, after adding ordinary sugar. Some microorganisms feel great in hot springs, in acid, eat methane or other chemicals.

Bacteria are the most ancient organisms and are very widespread in the world. They are found everywhere: at the bottom of the ocean, in the air, in the soil - even at great depth, in the body of living beings. Moreover, science has proved that bacterial cells inside a person are 10 times larger than their own. Some microorganisms simply live next to other living beings, while others interact actively with them. They can be beneficial or cause a variety of diseases. And useful bacteria are tens times more than pathogenic.

Many microorganisms are beneficial. For example, those that live in the human intestine, participate in digestion and protect it from infections. These are lactobacilli and bifidobacteria. About 40 million species of bacteria live in the human mouth, but only 5% of them are pathogenic. There are microorganisms that participate in the decomposition of waste. But, despite the fact that there are more beneficial bacteria, their pathogenic species bring a lot of harm, since they cause dangerous diseases. Until now, many people all over the world are dying of tuberculosis, cholera, tetanus, typhoid, botulism and other infections. Therefore, it is very important to learn how to properly interact with the world of bacteria.

Gram Method

Man has long been looking for ways to treat infectious diseases. After the existence of pathogenic bacteria was discovered, scientists try to classify them to find out how to deal with them. The best way was proposed in 1884 by a doctor Hans Christian Gram. It's pretty simple, but informative and is still used. According to this method, gram-positive and gram-negative bacteria differ.

Dr. Gram used a violet dye to study microorganisms and noticed that some of them are amenable to staining, others did not. He found out that this is due to the peculiarities of the bacterial cell walls. Since these microorganisms consist of one, rarely two cells, it is very important for them to have a strong shell. Therefore, the cell walls they have a complex structure. They protect the internal environment from the penetration of liquids. The structure of Gram-negative bacteria is the most difficult. They are resistant to penetration of saliva, gastric juice and other liquids.

The essence of the Gram method is that the test medium is treated with an aniline dye, fixed with iodine, and then washed off with alcohol. In this case, gram-negative bacteria discolour, and Gram-positive bacteria acquire a blue color. After repeated treatment with red dye, negative species can turn pink, and the dead microorganisms are colored brighter.

Application of the method in medicine

Gram's method for the separation of microorganisms into gram-positive and gram-negative bacteria promoted the improvement of microbiological studies. It helps to identify the resistance of pathogenic species to medicines, and develop new antibiotics to control them. After all, a strong cell wall of gram-negative bacteria makes them insensitive to conventional antibacterial drugs. A shell of Gram-positive microorganisms, although very thick, but permeable to liquids and antibiotics.

Gram-positive and Gram-negative bacteria

Gram's method allowed to divide all microorganisms into two large groups. Their characteristics and characteristics help to choose a more suitable treatment for infectious diseases. Gram-positive bacteria, which quickly turn blue in an aniline dye, form spores, exotoxins, so they are quite dangerous for health. But their membrane is permeable for antibacterial drugs.

Like gram-positive, gram-negative bacteria are the causative agents of serious diseases. They do not form a dispute, and in many cases are conditionally pathogenic. But under certain conditions they begin to release endotoxins and are the cause of severe inflammation and intoxication. Due to the complex structure of the cell wall, they are almost insensitive to antibiotics.

In the human body, both kinds of these microorganisms are contained. The correct ratio of gram-positive and gram-negative bacteria maintains the normal microflora of the vagina, intestine, and oral cavity. This helps protect the body from infections.

Gram-positive flora

Most bacteria that can be dyed with a violet dye, that is, have a permeable cell wall, are dangerous to humans. These include streptococci, staphylococci, listeria, bacilli, clostridia, mycobacteria, actinomycetes. Especially dangerous is Staphylococcus aureus, which affects the weakened body and without treatment quickly leads to the death of the patient. But they also include useful lactic acid lactobacilli.

Gram-positive microorganisms affect the respiratory tract, heart muscle, brain, skin. They provoke a purulent infection in the wounds, the infection of blood.

Diseases that they cause

It is Gram-positive bacteria that cause such common infectious diseases as:

  • Tonsillitis, pharyngitis;
  • Sinusitis, otitis media;
  • rheumatism;
  • blood poisoning;
  • pneumonia;
  • Inflammation of the brain;
  • anthrax;
  • Food poisoning;
  • botulism;
  • diphtheria;
  • tetanus;
  • Gas gangrene.

Gram-negative bacteria

The list is quite large, but there are many of them that do not do any harm to a person. These are basically conditionally pathogenic microorganisms. Under normal conditions, they live in the human body, without harming him. The most common are the following gram-negative bacteria. Their types are diverse:

  • Proteobacteria;
  • Pseudomonads;
  • Chlamydia;
  • Meningococci;
  • Brucella;
  • Spirochetes;
  • Gonococci;
  • Helicobacteria.

Microorganisms that do not stain violet are also resistant to any antibodies and antibacterial drugs. Therefore, the diseases caused by them are very difficult to treat.

What diseases cause

Under certain conditions, gram-negative bacteria cause serious illnesses. This is due to the fact that the complex shell of these microorganisms during the destruction releases a lot of toxins, which, when carried on the bloodstream of a person, cause the strongest intoxication. It turns out that pathogens are not bacteria themselves, but features of their cell membrane - the lipopolysaccharide layer, which causes an immune reaction of the body. They lead to the development of inflammation. But if a person's immunity is in order, he easily copes with such microorganisms, and the infection is not terrible for him.

Gram-negative bacteria include microorganisms that cause gonorrhea, syphilis, meningitis and respiratory diseases. Especially common are bacteria that cause damage to the respiratory and urinary tract, gastrointestinal tract. Gram-negative are such well-known pathogens of infections, as proteus, escherichia, enterobacteria, salmonella. They cause salmonellosis, meningitis, typhoid fever, dysentery. In addition, it is such resistant microorganisms that cause severe nosocomial infections. After all, they can survive even after serious disinfection.

Use of this knowledge in the treatment of diseases

When diagnosing the disease, Grama method is used to determine the most effective treatment to determine which microorganisms caused the disease: gram-positive or gram-negative bacteria. Antibiotics are prescribed depending on this. After all, the wrong treatment can only aggravate the situation.

To determine the causative agent, sputum, nasal or vaginal discharge, fecal, synovial or pleural fluid analysis is investigated. These samples are subjected to the Gram examination.

The most difficult to cure diseases caused by gram-negative bacteria. Basically they are affected by a combination of two antibiotics or preparations of a new generation. Effective against them can be "Ampicillin" or "Amoxicillin", "Chloramphenicol", "Streptomycin", and a group of cephalosporins. They can cope with the outer membrane of such bacteria.

Knowledge of the structure of the bacterial wall has made it possible to improve the effectiveness of the treatment of infectious diseases.

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