Development status: Approved, off-patent

Gram-negative activity

Mechanism of Action/Target pathogen: Disrupts the outer membrane by direct interaction with the lipid A component of the LPS and and disrupts the physical integrity of the phospholipid bilayer of the inner membrane, and possibly additional modes of action. Active against Gram-negative bacteria including Acinetobacter and Pseudomonas

Additional information: Natural product produced by Bacillus colistinus composed of a mixture of Polymyxins E1 and E2 (or Colistins A, B, and C). For systemic treatment it is used as the prodrug Colistimethate sodium (CMS) for topical use as Colistin sulfate. Nephrotoxic but still active in most cases of pan drug resistant Gram-negative bacteria.