Полимиксина B сульфа

The polymyxins are cationic peptides originally isolated from B. polymyxa. They bind and kill Gram-negative bacteria. The B series of polymyxins consist of a cyclic heptapeptide and a tripeptide side chain acylated at the amino terminus by a fatty acid. Polymyxin B (sulfate) is a mixture of at least four closely related components, polymyxin B₁ to B₄, with polymyxin B₁ and B₂ being the two major components. Polymyxin B (sulfate) has rapid in vitro bactericidal activity against major multidrug-resistant Gram-negative bacteria, such as P. aeruginosa, A. baumannii, and K. pneumoniae.

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Polymyxin B sulfate is used as topical antibiotic agent, often used in combination with neomycin; products include ointments, creams, eye, and ear drops.

Polymyxin B is one of a group of cyclic polypeptides elaborated by Bacillus polymyxa. The drug is a surface-active agent. It is thought to alter the lipoprotein membrane of bacteria so that it no longer functions as an effective barrier, thereby allowing the cell contents to escape. Polymyxin B is effective against Pseudomonas, E. coli, and other gram-negative bacteria except the Proteus and Serratia species. It has little effect on gram-positive organisms.

Polymyxin (Aerosporin) was discovered in 1947 almost simultaneouslyin three separate laboratories in the UnitedStates and Great Britain. As often happens whensimilar discoveries are made in widely separated laboratories,differences in nomenclature, referring to both theantibiotic-producing organism and the antibiotic itself, appearedin references to the polymyxins. Because the organismsfirst designated as Bacillus polymyxa and B.aerosporus Greer were found to be identical species, thename B. polymyxa is used to refer to all of the strains thatproduce the closely related polypeptides called polymyxins.Other organisms (e.g., see “Colistin” later) also producepolymyxins. Identified so far are polymyxins A, B1,B2, C, D1, D2, M, colistin A (polymyxin E1), colistin B(polymyxin E2), circulins A and B, and polypeptin. Theknown structures of this group and their properties havebeen reviewed by Vogler and Studer. Of these,polymyxin B as the sulfate usually is used in medicine because,when used systemically, it causes less kidney damagethan the others. Polymyxin B sulfate is a nearly odorless, white to buff powder. It is freely soluble in water and slightly soluble in alcohol.

Polymyxin B is produced by fermentation of Bacillus polymyxa. It is separated from a mixture of related cyclic peptides and is primarily active against Gram-negative microorganisms. It apparently binds to phosphate groups in bacterial cytoplasmic membranes and disrupts their integrity. It is used IM or IV as a sulfate salt to treat serious urinary tract infections, meningitis, and septicemia, primarily caused by Pseudomonas aeruginosa, but some other Gram-negative bacteria also will respond. Irrigation of the urinary bladder with solutions of polymyxin B sulfate is employed as well by some to reduce the incidence of infections subsequent to installation of indwelling catheters. Additionally, it is used ophthalmically to treat infections by P. aeruginosa. When given parenterally, the drug is neuro- and nephrotoxic and, therefore, is employed only after other drugs have failed.