Source:http://linkedlifedata.com/resource/umls/id/C0032535
MSH: A mixture of polymyxins B1 and B2, obtained from Bacillus polymyxa strains. They are basic polypeptides of about eight amino acids and have cationic detergent action on cell membranes. Polymyxin B is used for infections with gram-negative organisms, but may be neurotoxic and nephrotoxic.,NCI: A mixture of the polypeptides polymyxins B1 and B2, both obtained from Bacillus polymyxa strains, with antimicrobial activity. Polymyxin B exerts its antimicrobial effect through its cationic detergent action on cell membranes. Specifically, this antibiotic binds to the negatively charged site in the lipopolysaccharide layer of the bacterial cell membrane via electrostatic affinity with the positively charged amino groups in the cyclic peptide portion. Subsequently, the fatty acid portion of polymyxin B dissolves in the hydrophobic region of the bacterial cell membrane. This results in an alteration in cell membrane structure, disruption of cell wall integrity and an increase in permeability for water and molecules.