1,720,972 research outputs found
New peptidyl -beta-lactams: solution-solid phase synthesis for the preparation of antibiotic libraries
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Convergent Solution Phase and Solid Phase Synthesis for the Preparation of β-Lactam Antibiotic Libraries
No full textNew peptidyl-β-lactams: solution-solid phase synthesis for the preparation of antibiotic libraries.
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SAR and Anti-Mycobacterial Activity of Quinolones and Triazoloquinolones: An Update
No full textFluoroquinolones (FQ) are an important family of synthetic antimicrobial agents being clinically used over the
past thirty years. Currently some FQ are under investigation for the treatment of multidrug-resistant tuberculosis (MDRTB),
defined as resistance to at least isoniazid and rifampicin, and are under investigation as first-line drugs. Their main
biological target in Mycobacterium tuberculosis is the DNA gyrase, a topoisomerase II encoded by gyrA and gyrB that is
essential to maintain the DNA supercoil. It has been demonstrated that mutations in short regions of DNA gyrase are associated
with quinolone resistance or hypersusceptibility and take place in several MDR clinical isolates of M. tuberculosis.
In this article we update§ our previous review (Carta et al. Anti-infective agents, 2008, 7, 134-147) about the anti mycobacterial
properties, mode of action and structure activity relationship (SAR) studies of the known quinolone derivatives. Furthermore,
we update the synthesis and activity of 3,9-disubstituted-6-oxo-6,9-dihydro-3H-[1,2,3]-triazolo[4,5-
h,g]quinolone-carboxylic acids and their esters as a new class of potent and selective anti-mycobacterial agents, coupled
with absence of cytotoxicity. Furthermore, particularly interesting is their activity against MDR M. tuberculosis
A multicentre European study on the prevalence of glycopeptide resistance among clinical isolates of enterococci
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Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
European survey of vancomycin-resistant enterococci in at-risk hospital wards and in vitro susceptibility testing of ramoplanin against these isolates
No full textA survey in eight European countries, including 13 hospitals, of vancomycin-resistant enterococci (VRE) in at-risk hospital wards (such as the ICU and the haematology ward) was performed in 2001, and the in vitro susceptibility of the isolates ramoplanin and other drugs was tested. A total of 1314 non-duplicate clinical enterococcal isolates were collected, and 38 (2.9%) were vancomycin resistant: 27 Enterococcus faecium and 11 Enterococcus faecalis; 35 VanA and three VanB phenotypes. Rates of VRE among clinical enterococcal isolates varied between 0 and 1.7% for the participating countries, except the UK (10.4%) and Italy (19.6%). One hundred and twenty-three (3.5%) VRE were found among 3499 stool samples tested for the presence of these organisms: 111 (3.2%) E. faecium and 12 (0.3%) E. faecalis; 114 (3.3%) VanA and nine (0.3%) VanB phenotypes. Rates of intestinal colonization with VRE varied between 0 and 1.2% for the participating countries, except Italy (7.5%) and the UK (32.6%). In vitro susceptibility testing showed that the Italian and UK VRE are multi-resistant (including resistance to ampicillin and high-level resistance to gentamicin and streptomycin), and that ramoplanin was active against all strains of VRE, with an MIC90 of 0.5 mg/L for clinical isolates. Pulsed-field gel electrophoresis showed that the high prevalence of VRE in the Italian and UK centres was related to the monoclonal emergence and spread of three centre-specific clones. This survey suggests that in some centres in Europe, a similar situation may be encountered to that in the USA (monoclonal spread of multi-resistant VRE in at-risk wards)
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