KEY POINTS
- Polymyxin B works as a cationic detergent, damaging bacterial cytoplasmic membrane and causing leakage of intracellular contents
- Polymyxin E (colistin, colistmethate sodium) is very similar to polymyxin B in spectrum and toxicity
- See below resource “chalk and cheese” for a great comparison of the two
- Polymyxin E (colistin, colistmethate sodium) is very similar to polymyxin B in spectrum and toxicity
- Available as injectable and is used topical intra-operative as well
- Only used for Gram negative bacteria, like Pseudomonas aeruginosa and Acinetobacter baumannii
- A last-line antibiotic and is typically only used when few to no other options exist
- Strongly consider combination therapy when using this antibiotic
- Highly associated with nephrotoxicity
RESOURCES
- Polymyxin B Package Insert
- Polymyxins: antibacterial activity, susceptibility testing, and resistance mechanisms encoded by plasmids or chromosomes (CMR 2017)
- Nephrotoxicity of polymyxins: is there any difference between colistimethate and polymyxin B? (AAC 2016)
- Colistin and polymyxin B: peas in a pod, or chalk and cheese? (CID 2014)
- Top 5 unanswered questions with invasive drug-resistant Gram negative infections (2016)
- Polymyxin B & colistin tips sheet from Stanford Medicine
- Detailed polymyxin information from antimicrobe.org