What are Antibiotics?
What do Antibiotics do?
Antibiotics are a group of powerful medicines which fight against infections and can also save our lives when we use them correctly. They work either by stopping the bacterial reproduction or by destroying them completely. However, before bacteria are multiplied and cause symptoms, our immune system kills them. The white blood cells attack the harmful bacteria and even though it causes symptoms, our immune system can usually cope and fight with the infection. However, sometimes, when the harmful bacteria are excessive in number and our immune system cannot fight them, antibiotics are used.
If you know what is penicillin, you would know that it was the first-ever antibiotic to be discovered. There are several penicillin-based antibiotics like amoxicillin, ampicillin, and penicillin G, which are used even today in the treatment of several infections. There are many topical antibiotics available as well in the form of OTC ointments and creams.
Today we will discuss what are antibiotics, what do antibiotics do, what are antibiotics used for, and how long do antibiotics take to work.
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Antibiotics Definition
Let us now discuss the antibiotic meaning and its definition.
Antibiotics are defined as a type of an antimicrobial drug that is used for treating and preventing bacterial infections through the inhibition of the growth of bacteria. Antibiotics are not effective on the diseases that are caused due to viruses, like flu or cold.
History of Antibiotics
Let us discuss the penicillin meaning, penicillin history, how penicillin work, and take a look at what penicillin is used for.
Initially, the antibiotics were obtained from microorganisms. In the later years after the advancement of synthetic methods, antibiotics were developed synthetically.
In the nineteenth century, a German bacteriologist, Paul Ehrlich, started to look for a chemical which could kill bacteria in both the bodies of humans as well as animals, but which does not affect their health. After conducting several types of research, he discovered a medicine called arsphenamine, which is also called salvarsan. It was used in the treatment of syphilis, caused by the bacteria spirochete. He received a Nobel Prize for the same in the year 1908. Though this medicine had some side effects, its impact on the bacteria was so much more than on the humans.
In the year 1932, another drug known as prontosil was discovered by the group of researchers located at Bayer Laboratories. This was much similar to salvarsan that tends to convert into sulphanilamide when taken into the body.
However, the actual transformation in regards to the antibacterial therapy happened with the discovery which was made by Alexander Fleming in the year 1929, of the naturally developed antibiotic called penicillin.
How do Antibiotics Work?
Although there are many different kinds of antibiotics, they tend to work in two basic ways.
Certain antibiotics like penicillin tend to get rid of the bacteria when they kill it. They usually do so by disrupting the formation of the cell content or the cell wall of the bacteria.
The other kind of antibiotics tends to inhibit the multiplication action of the bacteria.
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Types of Antibiotics
Antibiotics are typically classified depending on their chemical structure. Antibiotics having the same structural class have similar properties when it comes to effectiveness, allergy potential, and toxicity. They are:
Penicillins
Macrolides
Sulfonamides
Cephalosporin
Tetracyclines
Fluoroquinolones
Aminoglycosides
Depending on how they work to stop the bacterial infection, they are classified as follows:
Bactericidal: They tend to kill the bacteria that is present in the body that causes diseases. Examples include penicillin, polymyxin, etc.
Bacteriostatic: They are the medicines that are used for inhibiting microbial growth. The examples include Chloramphenicol, Tetracycline, etc.
Depending on the range of action of antibiotics, they are classified as follows:
Broad Spectrum
These are the drugs which inhibit or destroy the growth of a huge range of both the gram-positive and the gram-negative bacteria. For e.g; Amoxicillin
Narrow Spectrum
These types of antibiotics typically attack Gram-positive bacteria or gram-negative bacteria. For e.g; Penicillin G
Limited Spectrum
These antibiotics are effective against a particular type of organism or even a disease.
What is Antibiotic Resistance?
The emergence of bacterial resistance to antibiotics is quite a common phenomenon. The emergence of bacterial resistance tends to often reflect on the evolutionary processes which take place during the time of the antibiotics therapy. The treatment of antibiotics might tend to select for the bacterial strains having genetically or physiologically enhanced capacity for surviving higher doses of the antibiotic medication. Under a few conditions, it can result in a preferential resistant bacterial growth, whereas the susceptible bacterial growth gets inhibited by the antibiotic.
FAQs on Antibiotics Types and Side Effects
1. What are antibiotics and how do they work against bacteria?
Antibiotics are a class of antimicrobial drugs used to treat and prevent bacterial infections. They work through two primary mechanisms: some are bactericidal, meaning they directly kill the bacteria, often by disrupting the formation of the bacterial cell wall. Others are bacteriostatic, meaning they inhibit the growth and reproduction of bacteria, allowing the body's immune system to eliminate them.
2. What are the main types of antibiotics based on their chemical structure?
Antibiotics are often classified into groups based on their chemical structure, which determines their mechanism of action and effectiveness. Key types include:
- Penicillins: One of the first discovered types, used for a wide range of infections.
- Cephalosporins: Structurally similar to penicillins, used for conditions like pneumonia and skin infections.
- Tetracyclines: Broad-spectrum antibiotics effective against various bacteria.
- Macrolides: Often used as an alternative for patients with penicillin allergies.
- Fluoroquinolones: Synthetic broad-spectrum antibiotics used for urinary tract and respiratory infections.
- Sulfonamides: Synthetic antimicrobials that interfere with bacterial folic acid synthesis.
3. What is the difference between broad-spectrum and narrow-spectrum antibiotics?
The difference lies in the range of bacteria they are effective against. Broad-spectrum antibiotics, like Amoxicillin, can act against a wide variety of both gram-positive and gram-negative bacteria. In contrast, narrow-spectrum antibiotics, such as Penicillin G, are effective only against a specific, limited group of bacteria. Doctors prefer narrow-spectrum antibiotics when the causative bacterium is identified to minimise disruption to the body's normal flora.
4. What are some common side effects associated with taking antibiotics?
While antibiotics are crucial for fighting infections, they can cause side effects. The most common ones affect the digestive system, including nausea, diarrhoea, and abdominal pain, as the medication can disrupt the natural balance of bacteria in the gut. Other potential side effects include fungal infections (like thrush), rashes, and in rare cases, severe allergic reactions.
5. Why are antibiotics completely ineffective against viral infections like the common cold or flu?
Antibiotics are ineffective against viruses because of fundamental biological differences. Antibiotics work by targeting specific structures or metabolic pathways in bacteria, such as their cell walls or protein synthesis machinery. Viruses lack these structures; they are not cells and must use the host's cellular machinery to replicate. Since antibiotics have no target to attack in a virus, they cannot treat viral illnesses.
6. How does the overuse or misuse of antibiotics lead to the development of antibiotic resistance?
Antibiotic resistance is an example of natural selection. Within any bacterial population, some individuals may have a natural mutation that makes them resistant to an antibiotic. When the antibiotic is used, it kills the susceptible bacteria, but the resistant ones survive and multiply. Overuse or incomplete courses of antibiotics accelerate this process, leading to the emergence of 'superbugs' that are difficult or impossible to treat with existing drugs.
7. What is meant by the 'selective toxicity' of an antibiotic?
Selective toxicity is the key principle that makes antibiotics effective. It refers to the ability of a drug to harm a target microorganism (like bacteria) without harming the host (human). Antibiotics achieve this by targeting structures unique to bacterial cells, such as:
- The peptidoglycan cell wall, which human cells do not have.
- Bacterial ribosomes (70S type), which are different from human ribosomes (80S type).
- Specific enzymes essential for bacterial survival, which are not present in humans.
8. Are 'stronger' broad-spectrum antibiotics always better for treating an infection?
No, a 'stronger' or broad-spectrum antibiotic is not always the better choice. The most effective treatment uses a narrow-spectrum antibiotic that specifically targets the identified pathogen. Using powerful broad-spectrum antibiotics unnecessarily can lead to two major problems: it kills beneficial bacteria in the body, which can cause side effects, and it significantly increases the risk of promoting antibiotic resistance. The ideal antibiotic is the one that is most targeted and least disruptive.
