scholarly journals Pharmacodynamics of Telavancin (TD-6424), a Novel Bactericidal Agent, against Gram-Positive Bacteria

2004 ◽  
Vol 48 (8) ◽  
pp. 3043-3050 ◽  
Author(s):  
Sharath S. Hegde ◽  
Noe Reyes ◽  
Tania Wiens ◽  
Nicole Vanasse ◽  
Robert Skinner ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Gram Positive ◽  
Time Curve ◽  
Once Daily ◽  
Gram Positive Bacteria ◽  
Resistant Strains ◽  
Vancomycin Resistant ◽  
Dose Dependent

ABSTRACT Telavancin (TD-6424) is a novel lipoglycopeptide that produces rapid and concentration-dependent killing of clinically relevant gram-positive organisms in vitro. The present studies evaluated the in vivo pharmacodynamics of telavancin in the mouse neutropenic thigh (MNT) and mouse subcutaneous infection (MSI) animal models. Pharmacokinetic-pharmacodynamic studies in the MNT model demonstrated that the 24-h area under the concentration-time curve (AUC)/MIC ratio was the best predictor of efficacy. Telavancin produced dose-dependent reduction of thigh titers of several organisms, including methicillin-susceptible Staphylococcus aureus (MSSA) and methicillin-resistant Staphylococcus aureus (MRSA), penicillin-susceptible and -resistant strains of Streptococcus pneumoniae, and vancomycin-resistant Enterococcus faecalis. The 50% effective dose (ED50) estimates for telavancin ranged from 0.5 to 6.6 mg/kg of body weight (administered intravenously), and titers were reduced by up to 3 log10 CFU/g from pretreatment values. Against MRSA ATCC 33591, telavancin was 4- and 30-fold more potent (on an ED50 basis) than vancomycin and linezolid, respectively. Against MSSA ATCC 13709, telavancin was 16- and 40-fold more potent than vancomycin and nafcillin, respectively. Telavancin, vancomycin, and linezolid were all efficacious and more potent against MRSA ATCC 33591 in the MSI model compared to the MNT model. This deviation in potency was, however, disproportionately greater for vancomycin and linezolid than for telavancin, suggesting that activity of telavancin is less affected by the immune status. The findings of these studies collectively suggest that once-daily dosing of telavancin may provide an effective approach for the treatment of clinically relevant infections with gram-positive organisms.

scholarly journals In Vitro and In Vivo Activities of DA-7867, a New Oxazolidinone, against Aerobic Gram-Positive Bacteria

2005 ◽  
Vol 49 (6) ◽  
pp. 2498-2500 ◽  
Author(s):  
Eun Jeong Yoon ◽  
Yeong Woo Jo ◽  
Sung Hak Choi ◽  
Tae Ho Lee ◽  
Jae Keol Rhee ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Streptococcus Pneumoniae ◽  
Gram Positive ◽  
Methicillin Resistant ◽  
Gram Positive Bacteria ◽  
Vancomycin Resistant Enterococci ◽  
Infection Models ◽  
Vancomycin Resistant

ABSTRACT In vitro and in vivo activities of DA-7867 were assessed against methicillin-resistant Staphylococcus aureus, vancomycin-resistant enterococci, and penicillin-resistant Streptococcus pneumoniae. All isolates were inhibited by DA-7867 at ≤0.78 μg/ml, a four-times-lower concentration than that of inhibition by linezolid. For murine infection models, DA-7867 also exhibited greater efficacy than linezolid against all isolates tested.

scholarly journals Postantibiotic Suppression of Growth of Erythromycin A-Susceptible and -Resistant Gram-Positive Bacteria by the Ketolides Telithromycin (HMR 3647) and HMR 3004

2000 ◽  
Vol 44 (6) ◽  
pp. 1749-1753 ◽  
Author(s):  
Wendy J. Munckhof ◽  
Glenn Borlace ◽  
John D. Turnidge
Keyword(s):  
Staphylococcus Aureus ◽  
Streptococcus Pneumoniae ◽  
Streptococcus Pyogenes ◽  
Gram Positive ◽  
Gram Positive Bacteria ◽  
Resistant Strains ◽  
Erythromycin A

ABSTRACT We investigated the in vitro postantibiotic effects (PAEs) of the ketolides telithromycin (HMR 3647) and HMR 3004 and analyzed the results using the sigmoid E max model. Mean maximum telithromycin PAEs against erythromycin A-susceptible strains of Staphylococcus aureus, Streptococcus pyogenes, and Streptococcus pneumoniae were 3.7, 8.9, and 9.7 h, respectively, while maximum PAEs for erythromycin A-resistant strains were much shorter. Mean maximum HMR 3004 PAEs were 3.2 to 4.4 h for all species.

scholarly journals RING finger E3 ligase PPP1R11 regulates TLR2 signaling and innate immunity

eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
Alison C McKelvey ◽  
Travis B Lear ◽  
Sarah R Dunn ◽  
John Evankovich ◽  
James D Londino ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Innate Immunity ◽  
Ring Finger ◽  
E3 Ligase ◽  
Gram Positive ◽  
Gram Positive Bacteria ◽  
Toll Like Receptor 2 ◽  
Ligand Stimulation

Toll-like receptor 2 (TLR2) is a pattern recognition receptor that recognizes many types of PAMPs that originate from gram-positive bacteria. Here we describe a novel mechanism regulating TLR2 protein expression and subsequent cytokine release through the ubiquitination and degradation of the receptor in response to ligand stimulation. We show a new mechanism in which an uncharacterized RING finger E3 ligase, PPP1R11, directly ubiquitinates TLR2 both in vitro and in vivo, which leads to TLR2 degradation and disruption of the signaling cascade. Lentiviral gene transfer or knockdown of PPP1R11 in mouse lungs significantly affects lung inflammation and the clearance of Staphylococcus aureus. There is a negative correlation between PPP1R11 and TLR2 levels in white blood cell samples isolated from patients with Staphylococcus aureus infections. These results suggest that PPP1R11 plays an important role in regulating innate immunity and gram-positive bacterial clearance by functioning, in part, through the ubiquitination and degradation of TLR2.

scholarly journals In vitro properties of antimicrobial bromotyrosine alkaloids

2006 ◽  
Vol 55 (4) ◽  
pp. 407-415 ◽  
Author(s):  
Neora Pick ◽  
Mamta Rawat ◽  
Dorit Arad ◽  
Jiong Lan ◽  
Junfa Fan ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Antimicrobial Agents ◽  
Lead Compound ◽  
Gram Positive ◽  
Gram Positive Bacteria ◽  
Monocytes And Macrophages ◽  
Natural Inhibitor ◽  
Low Toxicity ◽  
Vancomycin Resistant

A bromotyrosine alkaloid family of antimicrobial agents was synthesized using the known structure of a natural inhibitor of the mycobacterial mycothiol S-conjugate amidase (MCA) as a template. This series of compounds represents a novel class of anti-infective agents against Gram-positive pathogens, including mycobacteria and meticillin- and vancomycin-resistant Staphylococcus aureus. The fact that these compounds are active against mycobacterial strains in which the MCA gene is deleted and against Gram-positive bacteria lacking mycothiol suggests the existence of an alternative target for these compounds. One member of this family, EXEG1706, was identified as the lead compound possessing low MICs (2·5–25 μg ml−1) for several clinical isolates, whilst having low toxicity for THP-1 monocytes and macrophages.

scholarly journals In Vitro and In Vivo Activities of a Novel Cephalosporin, BMS-247243, against Organisms other than Staphylococci

2002 ◽  
Vol 46 (4) ◽  
pp. 1108-1111 ◽  
Author(s):  
Junius Clark ◽  
Joan C. Fung-Tomc ◽  
Beatrice Minassian ◽  
Yuan-Hwang Tsai ◽  
Hyekyung Yang ◽  
...  
Keyword(s):  
Streptococcus Pneumoniae ◽  
Enterococcus Faecalis ◽  
Enterococcus Faecium ◽  
Gram Positive ◽  
Methicillin Resistant ◽  
Gram Positive Bacteria ◽  
Resistant Species ◽  
Vancomycin Resistant

ABSTRACT BMS-247243, a novel cephalosporin inhibitory for methicillin-resistant staphylococci, primarily has activity against gram-positive bacteria. The activities of BMS-247243, cefotaxime, and ceftriaxone against streptococci and Streptococcus pneumoniae were similar. BMS-247243 inhibits Enterococcus faecalis but not Enterococcus faecium. BMS-247243 also inhibits many inherently vancomycin-resistant species (Leuconstoc, Lactobacillus, Pediococcus) and anaerobic gram-positive bacteria.

scholarly journals Mode of Action of Van-M-02, a Novel Glycopeptide Inhibitor of Peptidoglycan Synthesis, in Vancomycin-Resistant Bacteria

2009 ◽  
Vol 54 (2) ◽  
pp. 960-962 ◽  
Author(s):  
Kenji Miura ◽  
Hidenori Yamashiro ◽  
Kouichi Uotani ◽  
Satoshi Kojima ◽  
Takashi Yutsudo ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Inhibitory Activity ◽  
Mode Of Action ◽  
Resistant Bacteria ◽  
Gram Positive ◽  
Gram Positive Bacteria ◽  
Peptidoglycan Synthesis ◽  
Vancomycin Resistant Enterococci ◽  
Resistant Strains ◽  
Vancomycin Resistant

ABSTRACT Van-M-02, a novel glycopeptide, was revealed to exert potent activities against Gram-positive bacteria, including vancomycin-resistant enterococci (VRE) and vancomycin-resistant Staphylococcus aureus (VRSA). A crude assay system was then used to study the mode of action of Van-M-02 as a peptidoglycan synthesis model of both vancomycin-susceptible and -resistant strains. The results suggested that Van-M-02 inhibits the synthesis of lipid intermediates irrespective of their termini. This inhibitory activity may contribute to the anti-VRE and anti-VRSA activities observed.

scholarly journals In Vitro Activities of a New Ketolide, ABT-773, against Multidrug-Resistant Gram-Positive Cocci

2001 ◽  
Vol 45 (12) ◽  
pp. 3640-3643 ◽  
Author(s):  
Kavindra V. Singh ◽  
Kumthorn Malathum ◽  
Barbara E. Murray
Keyword(s):  
Staphylococcus Aureus ◽  
Enterococcus Faecium ◽  
Multidrug Resistant ◽  
Gram Positive ◽  
Methicillin Resistant ◽  
Gram Positive Bacteria ◽  
Vancomycin Resistant ◽  
Almost All ◽  
Gram Positive Cocci

ABSTRACT The in vitro activities of ABT-773 were evaluated against 324 strains of gram-positive bacteria, including multidrug-resistantStaphylococcus spp. and Enterococcus spp. ABT-773 had lower MIC ranges, MICs at which 50% of isolates are inhibited (MIC50s), and MIC90s than erythromycin or clindamycin for almost all isolates tested. The MICs of ABT-773 were also lower than those of quinupristin-dalfopristin (Q-D) for methicillin-susceptible Staphylococcus aureus,Rhodococcus spp., and Streptococcus spp., while the MICs of Q-D were lower than those of ABT-773 for methicillin-resistant S. aureus and Enterococcus faecium, including vancomycin-resistant isolates.

scholarly journals In Vitro Activities of Daptomycin, Vancomycin, Linezolid, and Quinupristin-Dalfopristin against Staphylococci and Enterococci, Including Vancomycin- Intermediate and -Resistant Strains

2000 ◽  
Vol 44 (4) ◽  
pp. 1062-1066 ◽  
Author(s):  
Michael J. Rybak ◽  
Ellie Hershberger ◽  
Tabitha Moldovan ◽  
Richard G. Grucz
Keyword(s):  
Multidrug Resistant ◽  
Gram Positive ◽  
Gram Positive Bacteria ◽  
Vancomycin Resistant Enterococci ◽  
Alternative Drug ◽  
Potential Alternative ◽  
Resistant Strains ◽  
Vancomycin Resistant ◽  
Time Kill

ABSTRACT The in vitro activity of daptomycin was compared with those of vancomycin, linezolid, and quinupristin-dalfopristin against a variety (n = 203) of gram-positive bacteria, including methicillin-resistant Staphylococcus aureus and S. epidermidis (MRSA and MRSE, respectively), vancomycin-resistant enterococci (VRE), and vancomycin-intermediate S. aureus(VISA). Overall, daptomycin was more active against all organisms tested, except Enterococcus faecium and VISA, against which its activity was similar to that of quinupristin-dalfopristin. In time-kill studies with MRSA, MRSE, VRE, and VISA, daptomycin demonstrated greater bactericidal activity than all other drugs tested, killing ≥3 log CFU/ml by 8 h. Daptomycin may be a potential alternative drug therapy for multidrug-resistant gram-positive organisms and warrants further investigation.

scholarly journals Daptomycin–β-Lactam Combinations in a Rabbit Model of Daptomycin-Nonsusceptible Methicillin-Resistant Staphylococcus aureus Endocarditis

2016 ◽  
Vol 60 (7) ◽  
pp. 3976-3979 ◽  
Author(s):  
Henry F. Chambers ◽  
Li Basuino ◽  
Stephanie M. Hamilton ◽  
Eun Ju Choo ◽  
Pamela Moise
Keyword(s):  
Staphylococcus Aureus ◽  
Rabbit Model ◽  
Beta Lactams ◽  
Once Daily ◽  
Methicillin Resistant ◽  
Content Type ◽  
Daily Dose ◽  
Resistant Strains

ABSTRACTBeta-lactams enhance thein vitroactivity of daptomycin against methicillin-resistant strains ofStaphylococcus aureus. Experiments were performed in a rabbit model of aortic valve endocarditis caused by methicillin-resistant daptomycin-nonsusceptibleS. aureusstrain CB5054 to determine if a cephalosporin, ceftriaxone, administered as a once-daily dose of 100 mg/kg of body weight, or a carbapenem, ertapenem, administered as a once-daily dose of 40 mg/kg, improved the efficacy of daptomycin, administered as a once-daily dose of 12 mg/kg. Daptomycin was ineffective alone in reducing organism densities compared to untreated controls in vegetations and spleen, but densities were 1.4 log10CFU/g lower in kidney. The combination of daptomycin plus ceftriaxone or daptomycin plus ertapenem reduced bacterial densities in all tissues compared to single agents, with 0.6 to 1.0 log10CFU/g fewer organisms in vegetations, 1.5 to 2.5 log10CFU/g fewer organisms in spleen, and 1.8 to 2.5 log10CFU/g fewer organisms in kidney, although differences were statistically significant only in spleen for daptomycin plus ceftriaxone and in kidney for daptomycin plus ertapenem. Drug exposures in rabbits were less than those achievable in humans, which may have limited thein vivoactivity, particularly in vegetations.

scholarly journals In Vitro Activities of Three New Dihydrofolate Reductase Inhibitors against Clinical Isolates of Gram-Positive Bacteria

2009 ◽  
Vol 53 (11) ◽  
pp. 4949-4952 ◽  
Author(s):  
Karen E. Bowker ◽  
Patrick Caspers ◽  
Bérengère Gaucher ◽  
Alasdair P. MacGowan
Keyword(s):  
Staphylococcus Aureus ◽  
Antimicrobial Agents ◽  
Washington Dc ◽  
Gram Positive ◽  
Gram Positive Bacteria ◽  
Reductase Inhibitors ◽  
Drug Classes ◽  
Vancomycin Resistant ◽  
Dihydrofolate Reductase Inhibitors

ABSTRACT BAL0030543, BAL0030544, and BAL0030545 are dihydrophthalazine inhibitors with in vitro potency against gram-positive pathogens. The MIC50s for methicillin (meticillin)-sensitive Staphylococcus aureus, methicillin-resistant Staphylococcus aureus, hetero-vancomycin-resistant Staphylococcus aureus, and vancomycin-resistant Staphylococcus aureus (VISA) range from 0.015 to 0.25 μg/ml (MIC90s ≤ 0.5 μg/ml). MIC50s for beta-hemolytic streptococci range from 0.03 to 0.06 μg/ml, MIC50s for Streptococcus pneumoniae range from 0.06 to 0.12 μg/ml, MIC50s for Listeria monocytogenes range from 0.015 to 0.06 μg/ml, and MIC50s for Streptococcus mitis are ≤0.015 μg/ml. These three dihydrophthalazine antifolates have improved potency compared to that of trimethoprim and activity against gram-positive pathogens resistant to other drug classes. (This work was presented in part at the 48th Interscience Conference on Antimicrobial Agents and Chemotherapy, Washington, DC, 2008 [1].)

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