Polymyxins are
cationic detergent
antibiotics, with a general structure of a cyclic
peptide with a long hydrophobic tail. They disrupt the
structure of the bacterial cell membrane by interacting with
its phospholipids. Polymyxins have a bactericidal effect on
Gram-negative bacilli, especially on pseudomonas and
coliform organisms. Polymyxin antibiotics are highly
neurotoxic and nephrotoxic, and very poorly absorbed from the
gastrointestinal tract.
Well known examples:
- Colistin
Polymyxin B
Surfactin
Polymyxin acts as an antibiotic by damaging the
cytoplasmic membrane of bacteria. Also polymyxins biological
source is Bacillius polymyxa.