Comparison of the binding of gram-negative bacterial endotoxin by polymyxin B sulphate, colistin sulphate and colistin sulphomethate sodium.
Polymyxins are cyclic polypeptide antibiotics. In addition to their bactericidal activity they bind lipid A and neutralize the biological effects of bacterial endotoxin. We have studied the three available polymyxin preparations: polymyxin B sulphate (PB), colistin sulphate (CS) and colistin sulphomethate sodium (CMS), and compared their endotoxin binding capacity at equivalent therapeutic dosage. Each polymyxin was bound to a column of Sepharose 4B and challenged with 5 micrograms of endotoxin from Escherichia coli O127:B8. Recovery of endotoxin in the eluate was measured by a quantitative Limulus lysate microassay. PB and CS bound 94% of the challenge dose, CMS 89% and the control column (Sepharose alone) 24%. These results suggest that parenteral CMS (the least toxic polymyxin) retains useful anti-endotoxin capacity, and that in neutropenic patients, oral polymyxin may exert both anti-endotoxin and antimicrobial effects.
D003091:Colistin / Q000031:analogs & derivatives* / Q000378:metabolism*; D004731:Endotoxins / Q000378:metabolism*; D004926:Escherichia coli; D008033:Limulus Test; D011112:Polymyxin B / Q000378:metabolism*; D011113:Polymyxins / Q000378:metabolism*
D004731:Endotoxins; D011113:Polymyxins; C004691:colistinmethanesulfonic acid; D011112:Polymyxin B; D003091:Colistin