Antibiotic

An antibiotic is a drug that kills or slows the growth of bacteria. Antibiotics are one class of antimicrobials, a larger group which also includes anti-viral, anti-fungal, and anti-parasitic drugs. They are relatively harmless to the host, and therefore can be used to treat infections. The term, coined by Selman Waksman, originally described only those formulations derived from living organisms, in contradistinction to "chemotherapeutic agents", which were purely synthetic. Nowadays the term "antibiotic" is also applied to synthetic antimicrobials, such as the sulfonamides. Antibiotics are small molecules with a molecular weight less than 2000. They are not enzymes.

Related Topics:
Drug - Bacteria - Antimicrobial - Treat - Infection - Selman Waksman - Synthetic - Sulfonamide - Molecule - Molecular weight - Enzyme

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Unlike previous treatments for infections, which included poisons such as strychnine and arsenic, antibiotics were labelled "magic bullets": drugs which targeted disease without harming the host. Antibiotics are not effective in viral, fungal and other nonbacterial infections, and individual antibiotics vary widely in their effectiveness on various types of bacteria. Some specific antibiotics (called "narrow-spectrum antibiotics") target either gram-negative or gram-positive bacteria, while others are more wide-spectrum antibiotics.

Related Topics:
Strychnine - Arsenic - Drug - Viral - Fungal - Gram-negative - Gram-positive

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The effectiveness of individual antibiotics varies with the location of the infection, the ability of the antibiotic to reach the site of infection, and the ability of the bacteria to resist or inactivate the antibiotic. Some antibiotics actually kill the bacteria (bactericidal), whereas others merely prevent the bacteria from multiplying (bacteriostatic) so that the host's immune system can overcome them.

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Oral antibiotics are the simplest approach when effective, with intravenous antibiotics reserved for more serious cases. Antibiotics may sometimes be administered topically, as with eyedrops or ointments.

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