Polymyxins


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Related to Polymyxins: colistin, Sulfonamides, Polyenes
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

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.

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.
References in periodicals archive ?
The growing epidemic of infections in the ICU caused by MDR pathogens has led clinicians to reconsider prescribing pPB and colistin (polymyxin E) drugs that were removed from use in the past because of their neuro-and nephro-toxicity.17 An earlier study evaluated the efficacy of PB in MDR pathogens when there is very narrow choice.18 In case of A.
Toxicity of polymyxins: a systematic review of the evidence from old and recent studies.
Patients who received polymyxin B treatment were selected from the hospital database and information on basic characteristics, laboratory results, therapeutic options, and outcomes was abstracted.
In Citrobacter spp resistance to polymyxin, aminoglycoside, quinolones, linezolid, vancomycin, macrolides, licosamide was 100% while 50% isolates were resistant to penicillin.
M2 EQUITYBITES-March 6, 2018-MicuRx awarded CARB-X's grant for innovative polymyxin antibiotic MRX-8
Molecular methods are rapid and more sensitive but are specific to the resistance genes examined and faced with the large number of molecular mechanisms conferring resistance to polymyxins, should only be used to screen mcr genes in clinical microbiology laboratories.
In this study, some reviving antibiotics, including fosfomycin and polymyxins, were found to be effective alternative treatments against CRE.
Bacteria which are intrinsically resistant to polymyxins include Gram-negative isolates like Burkholderia spp., Proteus spp., Providencia spp., Morganella morganii, and Serratia spp.
As of July 11, treatment was switched to the triple combination of meropenem (1 g IV TID), tigecycline (50 mg IV BID, after a 100 mg loading dose), and polymyxin B (500,000 units IV BID).
At this time, CDC recommends that Enterobacteriaceae isolates with a colistin or polymyxin B MIC >4 ftg/ml be tested for the presence of mcr-1; testing is available through CDC (5).
The nephrotoxicity and neurotoxicity are the main problems encountered in the clinical use of polymyxins. (2) Nephrotoxicity frequently appears within the first few days of treatment.