681 research outputs found

    Antimicrobial activity of dalbavancin tested against Gram-positive clinical isolates from Latin American medical centres

    Get PDF
    The activity of dalbavancin, a new semi-synthetic lipoglycopeptide antibiotic, was evaluated in comparison with other antibacterial agents against 1229 Gram-positive organisms collected from medical centres in Latin America. Dalbavancin was the most potent compound tested against isolates of Staphylococcus aureus (MIC50, 0.06 mg/L) and coagulase-negative staphylococci (MIC50, 0.03 mg/L), independently of methicillin susceptibility. Dalbavancin inhibited all Streptococcus pneumoniae isolates at less than or equal to 0.06 mg/L. Dalbavancin also demonstrated excellent activity against beta-haemolytic (MIC50, less than or equal to 0.008 mg/L) and viridans group (MIC50, 0.016 mg/L) streptococci. All vancomycin-susceptible Enterococcus spp. isolates were inhibited by dalbavancin at less than or equal to 0.25 mg/L, but some vancomycin-resistant Enterococcus spp. isolates were only inhibited by dalbavancin levels of greater than or equal to 8 mg/L. Dalbavancin exhibited excellent activity against isolates of Corynebacterium spp. and Listeria spp. Dalbavancin may provide an important therapeutic option for Gram-positive infections, excluding those caused by enterococci with VanA-type resistance.Universidade Federal de São Paulo, Div Infect Dis, São Paulo, BrazilJONES Grp, JMI Labs, N Liberty, IA USATufts Univ, Sch Med, Boston, MA 02111 USAUniversidade Federal de São Paulo, Div Infect Dis, São Paulo, BrazilWeb of Scienc

    Blind Normalization of Speech From Different Channels

    Full text link
    We show how to construct a channel-independent representation of speech that has propagated through a noisy reverberant channel. This is done by blindly rescaling the cepstral time series by a non-linear function, with the form of this scale function being determined by previously encountered cepstra from that channel. The rescaled form of the time series is an invariant property of it in the following sense: it is unaffected if the time series is transformed by any time-independent invertible distortion. Because a linear channel with stationary noise and impulse response transforms cepstra in this way, the new technique can be used to remove the channel dependence of a cepstral time series. In experiments, the method achieved greater channel-independence than cepstral mean normalization, and it was comparable to the combination of cepstral mean normalization and spectral subtraction, despite the fact that no measurements of channel noise or reverberations were required (unlike spectral subtraction).Comment: 25 pages, 7 figure

    Global assessment of the antimicrobial activity of polymyxin B against 54 731 clinical isolates of Gram-negative bacilli: report from the SENTRY antimicrobial surveillance programme (2001-2004)

    Get PDF
    In total, 54 731 Gram-negative bacilli isolated worldwide between 2001 and 2004 from diverse sites of infection were tested for susceptibility to polymyxin B by the broth reference microdilution method, with interpretation of results according to CLSI (formerly NCCLS) guidelines. Polymyxin B showed excellent potency and spectrum against 8705 Pseudomonas aeruginosa and 2621 Acinetobacter spp. isolates (MIC50, 98% susceptible) against Citrobacter spp., Escherichia coli and Klebsiella spp., but activity was more variable against Enterobacter spp. (MIC50, 8 mg/L) against Burkholderia cepacia (11.8% susceptible), Serratia spp. (5.4% susceptible), indole-positive Proteus spp. (1.3% susceptible) and Proteus mirabilis (0.7% susceptible).Universidade Federal de São Paulo, Div Infect Dis, BR-04025010 São Paulo, BrazilJMI Labs, N Liberty, IA USATufts Univ, Sch Med, Boston, MA 02111 USAUniversidade Federal de São Paulo, Div Infect Dis, BR-04025010 São Paulo, BrazilWeb of Scienc

    Trapping and relocating seals from salmonid fish farms in Tasmania, 1990-2000: was it a success?

    Get PDF
    In an effort to reduce the impact of seals on fish farms, the trapping and relocation of seals at Tasmanian salmonid farms began in 1990. To the end of May 2000,353 identified individual seals had been trapped in 672 capture events. Most were non-breeding male Australian fur seals (Arctocephalus pusillus doriftrus). The number of seals captured increased (from four in 1990 ro a peak of 164 in 1998) with the size and extent of the farms, and an increase in salmon production from 55 tonnes in 1986/87 to almost 10000 tonnes in 1999/2000. Of 586 capture events 52% were of seals that had been captured more than once. When seals are recaptured following trapping and relocation, this occurs on average 25 days after capture. Capture-mark-recapture calculations show that many seals in the vicinity of fish farms are not 'trappable', suggesting that trapping is only effective for certain individuals. Some individuals are recaptured many times, reflecting the predisposition of some individuals to be captured ('trap-happy'). Interaction is seasonal, with most seals trapped during winter, between May and September. The assessment of trends in capture rates is problematic, due to the lack of capture effort information from the farms. A further confounding factor has been the change in management practice both between farms and over time, as the use of predator nets has become more widespread. Two seals trapped at fish farms and fitted with satellite transmitters before relocation have either not returned to the farm or returned to the vicinity of farms and not interacted with them, although on one occasion the individual was trapped. The effectiveness of the relocation program as a management tool to reduce seal interactions cannot be quantified from the relocation data per se, but relocation does not stop seals interacting with farms

    Antimicrobial susceptibility patterns of unusual nonfermentative gram-negative bacilli isolated from Latin America: report from the SENTRY Antimicrobial Surveillance Program (1997-2002)

    Get PDF
    The antimicrobial susceptibility of 176 unusual non-fermentative gram-negative bacilli (NF-GNB) collected from Latin America region through the SENTRY Program between 1997 and 2002 was evaluated by broth microdilution according to the National Committee for Clinical Laboratory Standards (NCCLS) recommendations. Nearly 74% of the NF-BGN belonged to the following genera/species: Burkholderia spp. (83), Achromobacter spp. (25), Ralstonia pickettii (16), Alcaligenes spp. (12), and Cryseobacterium spp. (12). Generally, trimethoprim/sulfamethoxazole (MIC50, 16 µg/ml; 18.8% susceptible) and meropenem (MIC50, 8 µg/ml; 50% susceptible) against Ralstonia pickettii. Since selection of the most appropriate antimicrobial agents for testing and reporting has not been established by the NCCLS for many of NF-GNB species, results from large multicenter studies may help to guide the best empiric therapy.Universidade Federal de São Paulo (UNIFESP) Departamento de MedicinaJMI Laboratories The Jones GroupUNIFESP, Depto. de MedicinaSciEL

    Nitric oxide release from antimicrobial peptide hydrogels for wound healing

    Get PDF
    Nitric oxide (NO) is an endogenously produced molecule that has been implicated in several wound healing mechanisms. Its topical delivery may improve healing in acute or chronic wounds. In this study an antimicrobial peptide was synthesized which self-assembled upon a pH shift, forming a hydrogel. The peptide was chemically functionalized to incorporate a NO-donor moiety on lysine residues. The extent of the reaction was measured by ninhydrin assay and the NO release rate was quantified via the Griess reaction method. The resulting compound was evaluated for its antimicrobial activity against Escherichia coli, and its effect on collagen production by fibroblasts was assessed. Time-kill curves point to an initial increase in bactericidal activity of the functionalized peptide, and collagen production by human dermal fibroblasts when incubated with the NO-functionalized peptide showed a dose-dependent increase in the presence of the NO donor within a range of 0–20 µM.This work was financed by FEDER (Fundo Europeu de Desenvolvimento Regional) funds via COMPETE 2020 (Operacional Programme for Competitiveness and Internationalisation (POCI), Portugal 2020), and by Portuguese funds through FCT (Fundação para a Ciência e a Tecnologia/ Ministério da Ciência, Tecnologia e Ensino Superior) in the framework of the projects “Institute for Research and Innovation in Health Sciences” (POCI-01-0145-FEDER-007274) and PTDC/QUI-QFI/29914/2017, as well through the grant SFRH/BD/84914/2012. Thanks to FCT also for supporting Research Unit LAQV-REQUIMTE through the project UID/QUI/5006/2013
    corecore