Question

What is an antibiotic? Give two examples.

Answer 1

Hint: The introduction of antibiotics into medicine revolutionized the way infectious diseases were treated.

Complete answer:
An antibiotic is an antimicrobial drug that is active against bacteria. It is derived from living matter or micro-organism, that can be used to kill or prevent the growth of other micro-organisms. They are applied to either kill or inhibit the growth of bacteria. Some of the antibiotics also possess antiprotozoal activity. Two examples of antibiotics are- penicillin and chloramphenicol.

Additional information: The term ‘Antibiotic’ was coined by ‘Selman Waksman' in 1943. In 1928, Scottish bacteriologist Alexander Fleming noticed that colonies of bacteria growing on a culture plate had been unfavorably affected by a mold, Penicillium notatum, which had contaminated the culture. A decade later British biochemist Ernst Chain, Australian pathologist Howard Florey, and others isolated the ingredient responsible, penicillin, and showed that it was highly effective against many serious bacterial infections. This led to the discovery of ‘penicillin’, the first antibiotic.

Note: Between 1945 and 1972, average human life expectancy jumped by eight years, with antibiotics used to treat infections that were previously likely to kill patients. Today, antibiotics are one of the most common classes of drugs used in medicine and it has made possible the treatment of many of the complex medical ailments.
Antibiotics kill bacteria mainly through five mechanisms, they are-
- Inhibition of cell wall synthesis (the most common mechanism).
- Inhibition of protein synthesis (Translation)
- Alteration of cell membranes.
- Inhibition of nucleic acid synthesis.
- Antimetabolite activity.