Antimicrobial
Polymyxins (colistin)
Cationic outer-membrane detergent
pol-ee-MIX-ins
High-yield clue
Polymyxins bind lipid A of LPS and disorganize the Gram-negative outer membrane, and mcr-1 is the transferable resistance gene concept.
Overview
A cationic cyclic-peptide class (colistin/polymyxin E, polymyxin B) studied as a last-resort Gram-negative agent that disrupts the outer membrane by binding lipid A of LPS.
Classification
- Cationic cyclic peptide
- Binds lipid A of lipopolysaccharide
- Membrane-permeabilizing / bactericidal
- Aerobic Gram-negative spectrum
Lab & identification clues
- Outer-membrane disruption / LPS binding concept
- Plasmid-borne mcr-1 resistance vocabulary
- Broth microdilution testing preference concept
Associations
- Carbapenem-resistant Gram-negative reserve vocabulary
- Nephrotoxicity and neurotoxicity study framing
- Intrinsic resistance in Proteus and Serratia concept
Commonly confused with
- Lipopeptides (daptomycin)
- Aminoglycosides
Frequently asked questions
What is Polymyxins (colistin)?
A cationic cyclic-peptide class (colistin/polymyxin E, polymyxin B) studied as a last-resort Gram-negative agent that disrupts the outer membrane by binding lipid A of LPS.
What is the high-yield clue for Polymyxins (colistin)?
Polymyxins bind lipid A of LPS and disorganize the Gram-negative outer membrane, and mcr-1 is the transferable resistance gene concept.
What is Polymyxins (colistin) associated with?
Polymyxins (colistin) is associated with Carbapenem-resistant Gram-negative reserve vocabulary, Nephrotoxicity and neurotoxicity study framing, and Intrinsic resistance in Proteus and Serratia concept.
What is Polymyxins (colistin) commonly confused with?
Polymyxins (colistin) is commonly confused with Lipopeptides (daptomycin) and Aminoglycosides.
Original mechanism summary for microbiology study. Sources checked: CDC antimicrobial-resistance guidance, NCBI Bookshelf Medical Microbiology, and standard coursework frameworks; reviewed 2026-06. Covers class, mechanism, and resistance vocabulary only; no prescribing, dosing, or patient-specific treatment guidance.