The world of bacteria is amazingly diverse and very rich. They are found everywhere: in the air, soil, on human skin, on its mucous membranes. Under certain circumstances, bacteria become dangerous to humans, causing serious illness. Some of them are easily treated with antibiotics or even conventional antiseptics, while 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 back in the 19th century, but is still used today.
World of bacteria
The kingdom of microorganisms is so diverse and complex that even modern science has not yet fully explored 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 the addition of ordinary sugar. Some microorganismsthrive in hot springs, acid, 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 depths, in the body of living beings. Moreover, science has proven that bacteria cells inside a person are 10 times more than their own. Some microorganisms simply live next to other living things, while others actively interact with them. They can be beneficial or cause various diseases. Moreover, there are dozens of times more beneficial bacteria than pathogenic ones.
Many microorganisms are beneficial. For example, those that live in the human intestine are involved in digestion and protect it from infections. These are lactobacilli and bifidobacteria. About 40 million species of bacteria live in the human oral cavity, but only 5% of them are pathogenic. There are microorganisms that are involved in the decomposition of waste. But, despite the fact that there are still more beneficial bacteria, their pathogenic species do a lot of harm, as they cause dangerous diseases. Until now, many people around the world are dying from tuberculosis, cholera, tetanus, typhoid fever, 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. Once the existence of pathogenic bacteria has been discovered, scientists try to classify them in order to figure out how to deal with them. The best way was proposed in 1884 by the physician Hans Christian Gram. It is quite simple, but informative and is still used today. This method differentiates between Gram-positive and Gram-negative bacteria.
Dr. Gram used a purple dye to study microorganisms and noticed that some of them were stainable, while others were not. He found that this is due to the peculiarities of the cell walls of bacteria. Since these microorganisms consist of one, less often two cells, it is very important for them to have a strong shell. Therefore, their cell walls 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 the penetration of saliva, gastric juice and other fluids.
The essence of the Gram method is that the test medium is treated with aniline dye, fixed with iodine, and then washed off with alcohol. In this case, gram-negative bacteria become discolored, and gram-positive ones acquire a blue color. After re-treatment with red dye, negative species may turn pink, with dead microorganisms staining brighter.
Application of the method in medicine
The Gram method of separating microorganisms into Gram-positive and Gram-negative bacteria has contributed to the improvement of microbiological research. It helps to identify the resistance of pathogenic species to drugs, to develop new antibiotics to combat them. After all, strong cellularthe wall of gram-negative bacteria makes them insensitive to conventional antibacterial drugs. And the shell of gram-positive microorganisms, although very thick, is permeable to liquids and antibiotics.
Gram-positive and Gram-negative bacteria
Gram's method made it possible to divide all microorganisms into two large groups. Their features and characteristics help to choose a more appropriate treatment for infectious diseases. Gram-positive bacteria, which quickly stain blue with aniline dye, form spores, exotoxins, and therefore are quite dangerous to he alth. But their shell is permeable to antibacterial drugs.
Like gram-positive, gram-negative bacteria are the causative agents of serious diseases. They do not form spores, and in many cases are opportunistic pathogens. But under certain conditions, they begin to secrete endotoxins and cause severe inflammation and intoxication. Due to the complex structure of the cell wall, they are almost insensitive to antibiotics.
The human body contains both types of these microorganisms. The correct ratio of gram-positive and gram-negative bacteria maintains the normal microflora of the vagina, intestines, and oral cavity. This helps protect the body from infections.
Gram-positive flora
Most bacteria that can be stained with violet dye, that is, have a permeable cell wall, are dangerous to humans. These include streptococci,staphylococci, listeria, bacilli, clostridia, mycobacteria, actinomycetes. Staphylococcus aureus is especially dangerous, which affects a weakened body and, without treatment, quickly leads to the death of the patient. But they also include beneficial lactic acid bacteria.
Gram-positive microorganisms infect the respiratory tract, heart muscle, brain, skin. They provoke a purulent infection in wounds, blood poisoning.
The diseases they cause
It is Gram-positive bacteria that are the cause of such common infectious diseases as:
- tonsillitis, pharyngitis;
- sinusitis, otitis media;
- rheumatism;
- blood poisoning;
- pneumonia;
- brain inflammation;
- anthrax;
- food poisoning;
- botulism;
- diphtheria;
- tetanus;
- gas gangrene.
Gram-negative bacteria
The list of them is quite large, but among them there are many that do not bring any harm to humans. These include mainly opportunistic pathogens. Under normal conditions, they live in the human body without harming it. The most common are the following gram-negative bacteria. Their types are varied:
- proteobacteria;
- pseudomonas;
- chlamydia;
- meningococci;
- brucella;
- spirochetes;
- gonococci;
- helicobacteria.
Microorganisms that do not stain purple are also resistant to any antibodies and antibacterial drugs. Therefore, the diseases they cause are very difficult to treat.
What diseases cause
Under certain conditions, gram-negative bacteria cause serious illness. This is due to the fact that the complex shell of these microorganisms, when destroyed, releases many toxins, which, spreading through the human bloodstream, cause severe intoxication. It turns out that it is not the bacteria themselves that are pathogenic, but the features of their cell membrane - the lipopolysaccharide layer, which causes the body's immune response. They lead to inflammation. But if a person's immunity is in order, he can easily cope with such microorganisms, and he is not afraid of infection.
Gram-negative bacteria include those that cause gonorrhea, syphilis, meningitis, and respiratory infections. Especially common are such bacteria that cause damage to the respiratory and urinary tract, gastrointestinal tract. Gram-negative bacteria include such well-known infectious agents as Proteus, Escherichia, Enterobacteria, Salmonella. They cause salmonellosis, meningitis, typhoid fever, dysentery. In addition, it is these resistant microorganisms that cause severe nosocomial infections. After all, they can survive even after serious disinfection.
Useof this knowledge in the treatment of diseases
When diagnosing a disease to determine more effective treatment, the Gram method is necessarily used to determine which microorganisms caused the disease: gram-positive or gram-negative bacteria. Antibiotics are prescribed depending on this. After all, the wrong choice of treatment can only aggravate the situation.
To determine the pathogen, sputum, discharge from the nose or vagina, analysis of feces, synovial or pleural fluid are examined. These samples are subjected to a Gram examination.
The most difficult diseases to cure are those caused by Gram-negative bacteria. Basically, they are affected by a combination of two antibiotics or new generation drugs. Effective against them can be "Ampicillin" or "Amoxicillin", "Chloramphenicol", "Streptomycin", as well as a group of cephalosporins. They can handle the outer membrane of such bacteria.
Knowledge of the structure of the bacterial wall has improved the effectiveness of the treatment of infectious diseases.
