CAS 7722-44-3: (6R)-N-[(2S)-4-amino-1-{[(2S,3R)-1-{[(2S)-4-amino-1-oxo-1-{[(3S,6R,9S,12S,15R,18S,21S)-6,9,18-tris(2-aminoethyl)-3-[(1R)-1-hydroxyethyl]-12,15-bis(2-methylpropyl)-2,5,8,11,14,17,20-heptaoxo-1,4,7,10,13,16,19-heptaazacyclotricosan-21-yl]amino}butan-2-yl]am

Applications Colistin A Sulfate Hydrate is used as an antibiotic in the treatment of infectious diseases resulting from multi-drug resistant (MDR) gram-negative bacteria. References Wallace, S. et al.: J. Pharm. Sci., 102, 1578 (2013); Suzuki, T., et al.: J. Biochem., 54, 25 (1963); Barnett, M., et al.: Br. J. Pharmacol. Chemother., 23, 552 (1964); Littlewood, J, M., et al.: Respir. Med., 94, 632 (2000); Li, J., et al.: Int. J. Antimicrob. Ag., 25, 11 (2005); Tsubery, H. et al.: Antimicrob. Agents Chemother., 49, 3122 (2005)

Colistin A is an antimicrobial peptide, which is a type of polymyxin antibiotic derived from the bacterium *Paenibacillus polymyxa*. It exerts its bactericidal effect by interacting electrostatically with the lipopolysaccharides and phospholipids in the outer membrane of Gram-negative bacteria. This action disrupts the bacterial cell membrane, leading to increased permeability and cell death. Colistin A is particularly effective against multidrug-resistant Gram-negative pathogens such as *Pseudomonas aeruginosa*, *Acinetobacter baumannii*, and *Klebsiella pneumoniae*. It is often employed as a last-resort treatment for infections that are resistant to other antibiotics. Due to its nephrotoxic and neurotoxic potential, its use is usually reserved for severe infections where alternative treatments are ineffective or unavailable. Colistin A is a critical component in the therapeutic arsenal against antibiotic resistance and is subject to rigorous study to optimize its efficacy while minimizing adverse effects.

Colistin A, from Paenibacillus polymyxa, is an antibiotic effective against Gram-negative bacilli, part of the polymyxin class.