Polypeptide antibiotic

Polypeptide Antibiotic

Chemical structure of Bacitracin

A polypeptide antibiotic is a type of antibiotic that consists of a chain of amino acids linked by peptide bonds. These antibiotics are known for their ability to disrupt the cell membrane of bacteria, making them effective against a variety of bacterial infections.

Bacitracin

Bacitracin is a well-known example of a polypeptide antibiotic. It is produced by the bacterium Bacillus subtilis and is primarily used in topical applications due to its effectiveness against Gram-positive bacteria.

Mechanism of Action

Bacitracin works by interfering with the synthesis of the bacterial cell wall. It inhibits the dephosphorylation of bactoprenol, a lipid carrier molecule that transports peptidoglycan precursors across the cell membrane. This disruption in cell wall synthesis ultimately leads to bacterial cell death.

Clinical Uses

Bacitracin is commonly used in topical ointments for the treatment of skin infections, wounds, and burns. It is often combined with other antibiotics such as neomycin and polymyxin B in over-the-counter products to enhance its antibacterial spectrum.

Resistance

Resistance to bacitracin is relatively rare, but it can occur through the modification of the target site or increased efflux of the antibiotic from the bacterial cell. The use of bacitracin is generally limited to topical applications to minimize the development of resistance.

Related Pages

• Antibiotic
• Bacterial cell wall
• Gram-positive bacteria
• Peptidoglycan