Blog by Mufaddal IfuM Dewaswala
Antibiotics are compounds which are either of biological or chemical origin which stop the growth of bacteria or kill them. They act on various process of the bacteria like DNA replication, cell wall synthesis, protein synthesis etc.
They are divided into two groups:
Bacteriostatic (antibiotics which inhibit the growth)
Bactericidal (antibiotics which kill the organisms)
The bacteriostatic antibiotics stop the growth of the organisms until they are killed by the body's immune system they include some protein synthesis inhibitors.
Classes of antibiotics:
Antibiotics are classified among various classes with respect to their action, chemical structure, or spectrum of activity.
Action: As mentioned earlier, different antibiotics have different action such as inhibiting DNA replication, cell wall synthesis, protein synthesis etc.
Spectrum of activity: Microorganisms are of different types eg. gram postivie organisms, gram negative organisms, fungi etc. Due to the different modes of action the antibiotics maybe effective on some organisms and may not have any action on others.
Due to this, the antibiotics are classified as 'narrow spectrum antibiotics' which are effective against only a narrow range of bacteria while 'broad spectrum antibiotics' are effective on various types of bacteria.
Chemical structure: Classification usually is on the basis of chemical structures and chemical names.
Lists of various antibiotics and important examples
Protein synthesis inhibitors:
Aminoglycosides: Streptomycin, Gentamicin etc
Macrolides: Azithromycin, Erythromycin etc
Tetracyclines: Tetracycline, Doxycycline etc
Cell wall synthesis inhibitors:
Penicillins: Mithicillins, Penicillin G etc
Cephalosporin: Ceftobiprole, cefeprime etc
DNA synthesis inhibitors:
Quinolones: Ciprofloxacin, Norfloxacin etc
Folic acid inhibitors:
Sulfonamides: Sulfadiazine, Silver sulfadiazine etc
Production of antibiotics:
Antibiotics are produced by chemical methods or biological methods or both combined. Fungi like Streptomyces, Pencillium produce certain antibiotics in their stationary phase.
Some of the penicillins are first synthesised biologically by Peinicillium species and then the strutures of these penicillin are chemically modified to produce more effective antibiotics.
