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Streptogramins
Streptogramins are a class of antibiotics. Streptogramins are effective in the treatment of vancomycin-resistant ''Staphylococcus aureus'' (VRSA) and vancomycin-resistant ''Enterococcus'' (VRE), two of the most rapidly growing strains of multidrug-resistant bacteria. They fall into two groups: streptogramin A and streptogramin B. Members include: * Quinupristin/dalfopristin * Pristinamycin * Virginiamycin * NXL 103 Linopristin/flopristin (development codes NXL103 and XRP 2868) is an experimental drug candidate under development by Novexel. It is an oral streptogramin antibiotic that has potent ''in vitro'' activity against certain Gram-positive bacteria i ..., an experimental streptogramin in clinical trials for the treatment of respiratory tract infections. References Antibiotics {{antibiotic-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Streptogramin A
Streptogramin A is a group of antibiotics within the larger family of antibiotics known as streptogramins. They are synthesized by the bacteria '' Streptomyces virginiae''. The streptogramin family of antibiotics consists of two distinct groups: group A antibiotics contain a 23-membered unsaturated ring with lactone and peptide bonds while group B antibiotics are depsipeptides (lactone-cyclized peptides). While structurally different, these two groups of antibiotics act synergistically, providing greater antibiotic activity than the combined activity of the separate components. These antibiotics have until recently been commercially manufactured as feed additives in agriculture, although today there is increased interest in their ability to combat antibiotic-resistant bacteria, particularly vancomycin-resistant bacteria. Biosynthesis Streptogramin A is a polyketide in nature, but contains some amino acid components as well. Its gene cluster codes for a hybrid PKS-NRPS protein t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Streptogramin B
Streptogramin B is a subgroup of the streptogramin antibiotics family. These natural products are cyclic hexa- or hepta depsipeptides produced by various members of the genus of bacteria '' Streptomyces''. Many of the members of the streptogramins reported in the literature have the same structure and different names; for example, pristinamycin IA = vernamycin Bα = mikamycin B = osteogrycin B. Biosynthesis The biosynthesis of streptogramin B is carried out by large multifunctional enzymes called non-ribosomal peptide synthetases (NRPS). In the NRPS system, each amino acid is activated as an aminoacyladenylate and is linked to the enzyme as a thioester with a phosphopantetheinyl group. An elongation reaction then occurs by transferring the activated carboxyl to the amino group in the next amino acid, thus executing the N-to-C stepwise condensation. NRPSs contain several modules on a single polypeptide. Each of these modules can catalyze activation, condensation and a modification r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quinupristin/dalfopristin
Quinupristin/dalfopristin, or quinupristin-dalfopristin, (pronunciation: kwi NYOO pris tin / dal FOE pris tin) (trade name Synercid) is a combination of two antibiotics used to treat infections by staphylococci and by vancomycin-resistant ''Enterococcus faecium''. Quinupristin and dalfopristin are both streptogramin antibiotics, derived from pristinamycin. Quinupristin is derived from pristinamycin IA; dalfopristin from pristinamycin IIA. They are combined in a weight-to-weight ratio of 30% quinupristin to 70% dalfopristin. Administration Intravenous, usually 7.5 mg/kg every 8 hours (infections/life threatening VRSA); every 12 hours (skin infections). No renal dosing adjustments, hepatic dosing adjustments are not defined, consider reducing dose. Mechanism of action Quinupristin and dalfopristin are protein synthesis inhibitors in a synergistic manner. While each of the two is only a bacteriostatic agent, the combination shows bactericidal activity. *Dalfopristin binds to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pristinamycin
Pristinamycin ( INN), also spelled pristinamycine, is an antibiotic used primarily in the treatment of staphylococcal infections, and to a lesser extent streptococcal infections. It is a streptogramin group antibiotic, similar to virginiamycin, derived from the bacterium '' Streptomyces pristinaespiralis''. It is marketed in Europe by Sanofi-Aventis under the trade name Pyostacine. Pristinamycin is a mixture of two components that have a synergistic antibacterial action. Pristinamycin IA is a macrolide, and results in pristinamycin's having a similar spectrum of action to erythromycin. Pristinamycin IIA (streptogramin A) is a depsipeptide. PI and PII are coproduced by ''S. pristinaespiralis'' in a ratio of 30:70. Each compound binds to the bacterial 50 S ribosomal subunit and inhibits the elongation process of the protein synthesis, thereby exhibiting only a moderate bacteriostatic activity. However, the combination of both substances acts synergistically and leads to a potent b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Virginiamycin
Virginiamycin is a streptogramin antibiotic similar to pristinamycin and quinupristin/dalfopristin. It is a combination of pristinamycin IIA (virginiamycin M1) and virginiamycin S1. Virginiamycin is used in the fuel ethanol Ethanol (abbr. EtOH; also called ethyl alcohol, grain alcohol, drinking alcohol, or simply alcohol) is an organic compound. It is an alcohol with the chemical formula . Its formula can be also written as or (an ethyl group linked to a ... industry to prevent microbial contamination. It is also used in agriculture, specifically in livestock, to accelerate the growth of the animals and to prevent and treat infections. Antibiotics also save as much as 30% in feed costs among young swine, although the savings fade as pigs get older, according to a USDA study. References Combination antibiotics {{antiinfective-drug-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vancomycin-resistant Staphylococcus Aureus
Vancomycin-resistant ''Staphylococcus aureus'' (VRSA) are strains of ''Staphylococcus aureus'' that have become resistant to the glycopeptide antibiotic vancomycin. Mechanism of acquired resistance Strains of hVISA and vancomycin-intermediate ''Staphylococcus aureus'' (VISA) do not have resistant genes found in ''Enterococcus'' and the proposed mechanisms of resistance include the sequential mutations resulting in a thicker cell wall and the synthesis of excess amounts of D-ala-D-ala residues. VRSA strain acquired the vancomycin resistance gene cluster ''vanA'' from VRE. Diagnosis The diagnosis of vancomycin-resistant Staphylococcus aureus can be done with disk diffusion(and VA screen plate) Treatment of infection For isolates with a vancomycin minimum inhibitory concentration (MIC) , an alternative to vancomycin should be used. The approach is to treat with at least one agent to which VISA/VRSA is known to be susceptible by ''in vitro'' testing. The agents that are used i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vancomycin-resistant Enterococcus
Vancomycin-resistant ''Enterococcus'', or vancomycin-resistant enterococci (VRE), are bacterial strains of the genus ''Enterococcus'' that are resistant to the antibiotic vancomycin. Mechanism of acquired resistance Six different types of vancomycin resistance are shown by enterococcus: Van-A, Van-B, Van-C, Van-D, Van-E and Van-G. The significance is that Van-A VRE is resistant to both vancomycin and teicoplanin, Van-B VRE is resistant to vancomycin but susceptible to teicoplanin, and Van-C is only partly resistant to vancomycin. The mechanism of resistance to vancomycin found in enterococcus involves the alteration of the peptidoglycan synthesis pathway. The D-alanyl-D-lactate variation results in the loss of one hydrogen-bonding interaction (four, as opposed to five for D-alanyl-D-alanine) being possible between vancomycin and the peptide. The D-alanyl-D-serine variation causes a six-fold loss of affinity between vancomycin and the peptide, likely due to steric hindrance. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Multidrug-resistant Bacteria
Multidrug-resistant bacteria (MDR bacteria) are bacteria that are resistant to three or more classes of antimicrobial drugs. MDR bacteria have seen an increase in prevalence in recent years and pose serious risks to public health. MDR bacteria can be broken into 3 main categories: Gram-positive, Gram-negative, and other ( acid-stain). These bacteria employ various adaptations to avoid or mitigate the damage done by antimicrobials. With increased access to modern medicine there has been a sharp increase in the amount of antibiotics consumed. Given the abundant use of antibiotics there has been a considerable increase in the evolution of antimicrobial resistance factors, now outpacing the development of new antibiotics. Examples identified as serious threats to public health Examples of MDR bacteria identified as serious threats to public health include: ;Gram-positive MDR bacteria * ''Clostridioides difficile'' * '' Staphylococcus aureus'' * ''Streptococcus pneumoniae'' ;Gram-nega ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NXL 103
Linopristin/flopristin (development codes NXL103 and XRP 2868) is an experimental drug candidate under development by Novexel. It is an oral streptogramin antibiotic that has potent ''in vitro'' activity against certain Gram-positive bacteria including methicillin resistant ''Staphylococcus aureus'' (MRSA), as well as the important respiratory pathogens including penicillin-, macrolide- and quinolone-resistant strains.Novexel Reports Positive Phase II Trial Results With NXL103 in Adult Patients With Community Acquired Pneumonia , drugs.com It is a combination of [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
