How antibiotics work: when they are effective and useless
Some swallow antibiotics at the slightest runny nose, while others categorically refuse to take them even with severe pneumonia, considering them terribly harmful. Both that and other approach are absolutely incorrect.
Antibiotics really help cope with many serious infections, but only if taken correctly.
To understand in which case the drug will work, and in which it will be completely useless and even harmful, you need to imagine how the antibiotic works in the human body.
Antibiotic – what is this medicine?
Already in the name of this group of drugs lies the basic principle of their action: anti – against; biotic is life.
Antibiotics are substances of natural origin that have the ability to destroy other living microorganisms or prevent their reproduction. In nature, antibiotics are produced by certain microorganisms as products of their vital functions.
In pharmacology, antibiotics are used:
natural – grow microorganisms on nutrient media;
semi-synthetic – add other substances to natural to improve their properties;
synthetic – get completely by chemical synthesis.
Not all antibiotics are chemically produced
Strictly speaking, the latter are referred not to antibiotics, but to antimicrobials, but in everyday life we also call them antibiotics.
How do antibiotics work?
In simple terms, antibiotics act in two ways.
1. Destroy microorganisms, in which case they are called bactericidal. As a rule, they destroy the wall of the bacterium that protects it. And the bacterium dies.
2. Do not allow microorganisms to grow and multiply. These are the so-called bacteriostatic antibiotics. They act on the membrane through which the microorganism receives food and removes metabolic products – the cytoplasmic membrane.
As a result, the bacterial metabolism is disrupted and it ceases to develop. Another action of bacteriostatic antibiotics is aimed at suppressing protein synthesis in bacteria. The result is the same – the cell, as it were, freezes.
What antibiotics act and do not act
Infections are mainly caused by bacteria, viruses and fungi.
Antibiotics act on different types of bacteria and fungi.
Antibiotics do not work against viruses.
To understand why antibiotics are powerless against viral infections, you need to imagine what a bacterium and a virus are.
Antibiotics won’t help against viral infections
A bacterium is a unicellular microorganism, that is, a cell that lives in the body – on the skin and mucous membranes. Pathogenic bacteria can penetrate into human blood plasma (bacteremia). The antibiotic penetrates the bacterial cell and produces its destructive effect.
The virus is much smaller than bacteria, you can’t even see it in an ordinary microscope, only in an electronic one. It represents DNA or RNA (nucleic acids that carry genetic information), enclosed in a shell of protein. The virus is able to exist exclusively in a foreign cell. Penetrating into it and integrating into its genome, it begins to multiply, causing illness.
That is why the antibiotic is not able to cope with viruses – he simply can not get them.
When can antibiotics help?
Antibiotics are prescribed for bacterial infections of various organs and systems:
respiratory – bronchitis, pneumonia;
urinary – cystitis, pyelonephritis;
digestive – peptic ulcer, gastritis;
nervous – encephalitis, meningitis;
ENT organs – tonsillitis, otitis media, sinusitis;
skin – boils.
Special antibiotics work against fungal infections, tuberculosis, syphilis.
In diseases caused by viruses, antibiotics are prescribed if a bacterial infection joins the viral.
When do antibiotics fail?
1. Antibiotics will not help in case of viral diseases: influenza, SARS, childhood infections (measles, mumps, rubella, etc.), HIV, etc.
Before taking antibiotics, you need to consult a doctor
2. The antibiotic may not work if it is chosen incorrectly. So, there are antibiotics with a wide and narrow spectrum of action. The former work against various pathogenic microorganisms; the latter act only on specific groups of bacteria.
For example, penicillin preparations will be effective against gram-positive bacteria, but will not help with tuberculosis or infection caused by gram-negative bacteria.
3. A specific antibiotic may be useless if the pathogenic microorganism has resistance to it, that is, resistance.
Such resistance arises under the influence of bacterial mutations as a result of constant use of the drug. Bacteria are living organisms, and they tend to adapt to changing conditions. This property also causes resistance to a certain antibiotic. Moreover, bacteria can transmit this resistance to their next generations, and then the drug stops working against a certain bacterial infection.