HomeSearch by AntimicrobialPolymyxin E (Colistin)
Antimicrobial Name: Polymyxin E (Colistin)
Type of Antibiotic: Polypeptides II
Origin: Chemical/Synthetic
Functional Category: Antibiotic
Mechanism of Action: Colistin is polycationic and has both hydrophilic and lipophilic moieties. These poly cationic regions interact with the bacterial outer membrane, by displacing bacterial counter ions in the lipopolysaccharide. hydrophobic/hydrophillic regions interact with the cytoplasmic membrane just like a detergent, solubilizing the membrane in an aqueous environment. This effect is bactericidal even in an isosmolaric environment.
Comments:

Polymyxin E (Colistin) is a polymyxin antibiotic produced by certain strains of Bacillus polymyxa var. colistinus. Colistin is a mixture of cyclic polypeptides colistin A and B. Colistin is effective against most Gram-negative bacilli and is used as a polypeptide antibiotic. It is one of the last resort antibiotics for multidrug resistant Pseudomonas aeruginosa, and Acinetobacter. New Delhi metallo-β-Lactamase multidrug-resistant Enterobacteriaceae have also shown susceptibility to Colistin.