These are substance produced by micro-organisms or synthetic compounds, which suppress the growth or kill other micro-organisms.
These are a group of semi synthetic antibiotics derived from ‘Cephalosporin-C’ obtained from a fungus Cephalosporium acremonium.
Mechanism of action :
Cephalosporins are bactericidal and have the same mode of action as other beta-lactam antibiotics (such as penicillin).
Cephalosporins disrupt the synthesis of the peptidoglycan layer of bacterial cell walls.
The peptidoglycan layer is important for cell wall structural integrity.
It is active against both Gram-positive and Gram-negative organisms.
These has been conventionally classified into four generations.
This is based on chronological sequence of development, but more importantly ,takes into consideration the overall antibacterial spectrum as well as potency.
First-generation cephalosporins are predominantly active against Gram-positive bacteria, and successive generations have increased activity against Gram-negative bacteria (albeit often with reduced activity against Gram-positive organisms).
Developed in 1960, active against Gm+ weaker on Gm- orgnisms.
Cephalothin: 1 st cephalosporin used. (Parenteral)
active against: Streptococci, Staphylococci, gonococci, meningococci, C.diptheriae and clostridia.