Polymyxins


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Related to Polymyxins: colistin, Sulfonamides, Polyenes

Polymyxins

 

a group of polypeptide antibiotics, or acylcy-clopeptides, produced by certain strains of bacilli, primarily Bacillus polymyxa. The molecules of most polymyxins contain residues of threonine, lucine, α,γ-diaminobutyric acid, and 6-methyloctanoic acid.

Polymyxins are active only against gram-negative bacteria such as Pseudomonas aeruginosa, dysentery causative agent, Escherichia coli, Salmonellae, and Klebsiellae. The antimicrobial mechanism in polymyxins is associated with damage to the membrane of the bacterial cell. Polymyxins are differentiated by their nature and by the intensity of their side effects, which are chiefly neurotoxic and nephrotoxic and which restrict their use. Polymyxins B, M, and E (colistin) are used in medical practice.

References in periodicals archive ?
Aleksandar Danilovski, said, "As the world's leading supplier of both polymyxin B and colistin, Xellia has the experience and capability to develop new, polymyxin-like drugs with less side-effects.
The NAB compounds are polymyxin derivatives that have less cationic charges than the polymyxins currently in clinical use.
the developer of novel polymyxin derivatives for the treatment of infections caused by multidrug-resistant Gram-negative bacteria, revealed today animal efficacy and pharmacokinetic data from their NAB compounds at the 48th Annual ICAAC/IDSA 46th Annual Meeting in Washington, DC.
Just 60% of respondents said polymyxins were available in their hospitals, and only a quarter said they were on formulary.
The derivatives contain three positive charges only, while polymyxin B and colistin have five.
coli (including ESBL-producing strains) the MIC90 is identical to that of polymyxin B.
Susceptibility to polymyxins was not considered in these criteria because susceptibility testing for these drugs is not routinely performed.
Thus, more toxic agents such as polymyxins have been used as alternative therapeutic drugs against multidrug-resistant Acinetobacter infections (5,6).
The similar has been shown for combination with polymyxin B; furthermore, the myrtle essential oil resulted in re-sensitization of the MDR wound isolates, i.
The polymyxin group of antibiotics was discovered in the 1940s, [9,10] but their popularity soon faded due to reports of nephrotoxicity and the availability of safer antibiotics in the 1970s.
Only polymyxin (colistin) can be said to be reliable with 97% susceptibility.