VerifiedHint: The literal meaning of the term antibiotics is ‘against life’. Antibiotics are medicines that are used to treat several diseases like tuberculosis, cholera, etc which are caused by either bacteria or other microorganisms. They are produced by bacteria to kill other bacteria or microorganisms.
Complete Answer:
Antibiotics are chemical substances that are used against bacteria i.e. they are antibacterial in nature. These are used to treat various infections as these antibiotics either kill the bacterial causing disease or inhibit their reproduction. They are also used for treating protozoan diseases. But antibiotics do not kill viruses so they are not effective in viral diseases such as common cold.
The five examples of bacteria producing antibiotics are:
(I) Cephalosporium acremonium- It produces antibiotic cephalosporin.
(II) Streptomyces griseus- It produces antibiotic streptomycin.
(III) Streptomyces orientalis- It produces antibiotic vancomycin.
(IV) Penicillium griseofulvum- It produces antibiotic griseofulvin.
(V) Micromonospora purpurea- It produces antibiotic gentamicin.
- The different antibiotics have different mechanisms of action. Some antibiotics inhibit the bacterial cell wall synthesis, some inhibit protein synthesis in the bacteria, some interfere with RNA synthesis in bacteria, etc.
- Based on their activity, antibiotics are categorized as narrow spectrum and broad spectrum. Narrow spectrum antibiotics primarily affect gram positive bacteria while broad spectrum antibiotics affect both gram positive and gram negative bacteria. Tetracycline is an example of broad spectrum antibiotics and penicillin G is an example of narrow spectrum antibiotics.
Note: Penicillin was the first antibiotic discovered by Alexander Fleming in 1929. It was obtained from <i>Penicillium notatum</i> that inhibited the growth of <i>Staphylococcus aureus</i> in the petri plate.
