Tyrothricin

Tyrothricin is a mixture of antibiotics that is produced by the bacterium Bacillus brevis. It is composed of two cyclic polypeptides, gramicidin and tyrocidine, which constitute about 80% and 20% of tyrothricin, respectively. Tyrothricin is used topically in the treatment of skin infections and infected superficial wounds.

History

Tyrothricin was discovered in 1939 by the American microbiologist Rene Dubos, who was working at the Rockefeller Institute. It was the first antibiotic to be commercially manufactured and sold.

Composition

Tyrothricin is composed of two cyclic polypeptides, gramicidin and tyrocidine. Gramicidin makes up about 80% of the mixture, while tyrocidine constitutes the remaining 20%. Both of these polypeptides are produced by the bacterium Bacillus brevis.

Mechanism of action

Tyrothricin works by disrupting the cell membrane of bacteria, causing the contents of the cells to leak out, which leads to cell death. The two components of tyrothricin, gramicidin and tyrocidine, have different mechanisms of action. Gramicidin forms channels in the cell membrane, allowing ions to pass through, while tyrocidine disrupts the cell membrane's structure.

Medical uses

Tyrothricin is used topically to treat skin infections and infected superficial wounds. It is not used systemically because it can cause damage to the kidneys and nervous system.

Side effects

The most common side effects of tyrothricin are skin irritation and allergic reactions. In rare cases, it can cause damage to the kidneys and nervous system if it is absorbed into the bloodstream.

See also

• Antibiotic
• Bacillus brevis
• Gramicidin
• Tyrocidine

• Tyrothricin
  Tyrothricin