The Renaissance of Polymyxins

Polymyxins are polypeptide antibiotics, with a primary effect of membrane damaging due to their selective binding to the lipopolysaccharide of Gram-negative bacteria. Their nephro- and neurotoxic side effects limited their use, however, in the last decade the emergence of multidrug-resistant Gram-negative bacteria led to the reintroduction of polymyxins into clinical practice. This review provides an overview about the history and the latest developments of polymyxins. We describe the antimicrobial effects, pharmacodynamics, pharmacokinetics and different routes of administration. We highlight natural classic polymyxins, namely polymyxin B and E, the non-classic agents polymyxin M, S and T. Novel polymyxin chemical structure derivatives will be listed including NAB739, NAB740, NAB741 and NAB7061, that can have important therapeutical role in the future. Keywords: Antimicrobial activity, colistin, mechanism of action, polymyxin B, polymyxin derivatives, structure-activity relationship, toxicity.