Activity of quinupristin/dalfopristin and its components against Haemophilus influenzae
James H. Jorgensen,M L McElmeel +1 more
TLDR
Unlike the synergic activity noted against Gram-positive bacteria, the activity of quinupristin/dalfopristin against H. influenzae appears to be due almost entirely to the dalfopristsin component of the combination.Abstract:
Quinupristin/dalfopristin is an injectable streptogramin antibiotic that is constituted in a 30:70 (w/w) ratio of the two components. Quinupristin and dalfopristin are thought to act synergically by binding to two separate sites on the bacterial 50S ribosomal subunit. The in-vitro activities of the two components separately and together in different ratios were determined for a collection of 100 Haemophilus influenzae strains representing various antimicrobial resistance phenotypes. The NCCLS microdilution susceptibility testing procedure incorporating Haemophilus test medium (HTM) broth was used to determine MICs of quinupristin, dalfopristin and seven other antimicrobial agents. The MIC 50 and MIC 90 values were 4 and 8, 4 and 16, and 64 and 128 mg/L for quinupristin/dalfopristin (30:70), dalfopristin and quinupristin, respectively. MICs of quinupristin and dalfopristin were also determined in Mueller-Hinton lysed horse blood broth and by HTM agar dilution testing. Compared with HTM broth-derived results, the MICs of quinupristin/dalfopristin and its components were the same or one dilution higher in lysed horse blood and HTM agar incubated in air, and were equivalent or one dilution lower in HTM agar incubated in a CO 2 atmosphere. The MICs of quinupristin and dalfopristin separately or together were directly proportional to erythromycin MICs, but were otherwise unaffected by any of the resistance mechanisms represented in these strains. MICs of quinupristin and dalfopristin combined in ratios of 10:90, 70:30 and 90:10 did not differ significantly from those of the 30:70 ratio. Thus, unlike the synergic activity noted against Gram-positive bacteria, the activity of quinupristin/ dalfopristin against H. influenzae appears to be due almost entirely to the dalfopristin component of the combination.read more
Citations
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Journal ArticleDOI
Quinupristin/dalfopristin: a therapeutic review.
TL;DR: The results of comparative clinical trials suggest that quinupristin/dalfopristin has similar efficacy to that of commonly used antibiotics, including cefazolin, oxacillin, and vancomycin, in patients with skin and skin-structure infections or nosocomial pneumonia.
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In vitro activity of macrolides against traditional susceptible bacteria
TL;DR: Antibiotics belonging to the macrolide class have been in use for almost 40 years and are considered to be among the best-tolerated antibiotics.
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Streptogramins and their Potential Role in Geriatric Medicine
TL;DR: Streptogramins may offer a useful alternative in the treatment of infections in the elderly due to their coverage of organisms commonly causing infections in this population and because of their favourable pharmacokinetic profiles.
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L A Collins,G J Malanoski,George M. Eliopoulos,Christine Wennersten,Mary Jane Ferraro,Robert C. Moellering +5 more
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