Monitoring of the Pre-Equilibrium Step in the Alkyne Hydration Reaction Catalyzed by Au(III) Complexes: A Computational Study Based on Experimental Evidences.

The coordination ability of the [(ppy)Au(IPr)] fragment [ppy = 2-phenylpyridine, IPr = 1,3-(2,6-di-isopropylphenyl)-imidazol-2-ylidene] towards different anionic and neutral X ligands (X = Cl, BF, OTf, HO, 2-butyne, 3-hexyne) commonly involved in the crucial pre-equilibrium step of the alkyne hydration reaction is computationally investigated to shed light on unexpected experimental observations on its catalytic activity. Experiment reveals that BF and OTf have very similar coordination ability towards [(ppy)Au(IPr)] and slightly less than water, whereas the alkyne complex could not be observed in solution at least at the NMR sensitivity. Due to the steric hindrance/dispersion interaction balance between X and IPr, the [(ppy)Au(IPr)] fragment is computationally found to be much less selective than a model [(ppy)Au(NHC)] (NHC = 1,3-dimethylimidazol-2-ylidene) fragment towards the different ligands, in particular OTf and BF, in agreement with experiment.

In vitro activities of posaconazole, fluconazole, itraconazole, voriconazole, and amphotericin B against a large collection of clinically important molds and yeasts.

The in vitro activity of the novel triazole antifungal agent posaconazole (Noxafil; SCH 56592) was assessed in 45 laboratories against approximately 19,000 clinically important strains of yeasts and molds. The activity of posaconazole was compared with those of itraconazole, fluconazole, voriconazole, and amphotericin B against subsets of the isolates. Strains were tested utilizing Clinical and Laboratory Standards Institute broth microdilution methods using RPMI 1640 medium (except for amphotericin B, which was frequently tested in antibiotic medium 3).

Application of real-time quantitative PCR to molecular analysis of Candida albicans strains exhibiting reduced susceptibility to azoles.

Real-time quantitative PCR was used to measure expression levels of genes encoding efflux pumps, ERG11 and two control genes, ACT1 and PMA1, in a collection of 14 fluconazole-susceptible Candida albicans isolates. For each gene, average expression levels and variations within the population were determined. These values were then used as reference points to make predictions about the molecular basis of resistance in 38 clinical isolates (the majority of which were resistant to fluconazole) obtained from 18 patients treated with posaconazole for refractory oropharyngeal candidiasis.

In vitro activity of evernimicin and selected antibiotics against methicillin-resistant staphylococci: a 24-country study.

Objective: To collect and analyze data on susceptibility of methicillin-resistant staphylococci to evernimicin and other antimicrobial agents.

Methods: Recent clinical isolates of methicillin-resistant staphylococci from 33 laboratories in North America, Europe and South Africa were investigated.

Results: Of the antimicrobial agents tested, evernimicin had the lowest MIC90s for methicillin-resistant Staphylococcus aureus and methicillin-resistant coagulase-negative staphylococci (0.

In vitro Gram-positive antimicrobial activity of evernimicin (SCH 27899), a novel oligosaccharide, compared with other antimicrobials: a multicentre international trial.

The antimicrobial activity of evernimicin (formerly SCH 27899), a novel oligosaccharide antimicrobial of the everninomicin class, was evaluated against four groups of Gram-positive pathogens: (i) Streptococcus pneumoniae (n = 1452); (ii) methicillin- or oxacillin-resistant Staphylococcus aureus (MRSA) and coagulase-negative staphylococci (MR-CoNS; n = 1427); (iii) enterococci (n = 1517); and (iv) non-pneumococcal streptococci (n = 1388), using the Etest method at each study centre throughout Eastern and Western Europe, Scandinavia, South Africa, Turkey and North America. Comparative MICs were determined for a variety of reference compounds, including vancomycin, quinupristin/dalfopristin, chloramphenicol, penicillin, ampicillin, oxacillin, ceftriaxone and ciprofloxacin. Evernimicin was highly active against all strains tested, with MIC90 values < or = 1.