[Chemistry Class Notes] on Antibiotics Types and Side Effects Pdf for Exam

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.

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.

1. 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.

2. The other kind of antibiotics tends to inhibit the multiplication action of the bacteria.

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:

1. Penicillins

2. Macrolides

3. Sulfonamides

4. Cephalosporin

5. Tetracyclines

6. Fluoroquinolones

7. 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:

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

These types of antibiotics typically attack Gram-positive bacteria or gram-negative bacteria. For e.g; Penicillin G

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.