Tuesday, July 15, 2014

In Search of New Classes of Antibiotics

Over the history of medicine, the development of antibiotics (1930 – 1980) to combat virulent and dangerous infections has saved countless lives and helped avoid the onset of dangerous pandemics.  The use of these antibiotics has been of immense value in increasing the longevity of human populations.

Antibiotics currently fit into five classes as described in the following table –

Class
Mode of Action
Example
Β-lactam
Inhibits bacterial cell wall biosynthesis
Penicillin
Aminoglycoside
Inhibits protein synthesis in Gram-negative bacteria  such as Streptomyces griseus
Neomycin
Macrolide
Inhibits protein synthesis in Gram-positive bacteria such as Streptococcus pneumoniae by preferentially binding to the  50S component of the bacterial ribosome
Erythromycin
Tetracycline
Inhbits protein synthesis by preferentially binding to the  30S component of the bacterial ribosome
Tetracycline
Fluoroquinolone
Irreversibly binds to and inactivates key enzymes that maintain bacterial DNA
Norfloxacin

Note: Antibiotics are of no use in treating viral infections since the biology of the virus is markedly different than that of bacterial agents.


However, no new classes of antibiotics have been developed since 1980 and the overuse of the standard antibiotics has led to the insidious development of antibiotic –resistant strains of disease like tuberculosis (TB) and gonorrhea.  From a public health perspective, it is of enormous importance to encourage the development of new classes of antibiotics with unique modes of action.

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