Publications by authors named "Ziad Tarazi"

Early efforts to broaden the spectrum and potency of cyclic boronic acid β-lactamase inhibitor vaborbactam included a series of 7-membered ring boronates. Exploration of stereoisomers and incorporation of heteroatoms allowed identification of the all-carbon cyclic boronate with substituents trans as the preferred core structure, showing inhibition of Class A and C enzymes. Crystal structures of one analog bound to important β-lactamase enzymes were obtained.

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In recognition of the need for effective oral therapies to treat Gram-negative bacterial infections, efforts were directed toward identifying an oral prodrug of β-lactamase inhibitor clinical candidate QPX7728. Seventeen prodrugs were synthesized; key properties investigated were rates of cleavage to the active form in vitro, pharmacokinetics across species, and crystallinity. Compound (QPX7831 Sodium) emerged with optimal properties across all key attributes.

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Resistance to beta-lactams has created a major clinical issue. QPX7728 is a novel ultrabroad-spectrum cyclic boronic acid beta-lactamase inhibitor with activity against both serine and metallo-beta-lactamases developed to address this resistance for use in combination with beta-lactam antibiotics. The objective of these studies was to evaluate the activity of QPX7728 in combination with multiple beta-lactams against carbapenem-resistant isolates in a neutropenic mouse thigh infection model.

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Despite major advances in the β-lactamase inhibitor field, certain enzymes remain refractory to inhibition by agents recently introduced. Most important among these are the class B (metallo) enzyme NDM-1 of Enterobacteriaceae and the class D (OXA) enzymes of . Continuing the boronic acid program that led to vaborbactam, efforts were directed toward expanding the spectrum to allow treatment of a wider range of organisms.

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infections are difficult to treat and have limited treatment options. Carbapenems, including meropenem, are currently considered the first-line agents for the treatment of infections caused by spp. The percentage of a 24-hour period that the concentration of free drug in plasma is above the MIC (%24-h T>MIC) to achieve stasis, 1 log CFU, or 2 log CFU of bacterial killing against has not been studied previously for meropenem.

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Vaborbactam is a novel beta-lactamase inhibitor with activity against important beta-lactamases, in particular, serine carbapenemases, and is currently approved in combination with meropenem as Vabomere for the treatment of complicated urinary tract infections, including pyelonephritis. This combination is highly active against Gram-negative pathogens, especially carbapenemase (KPC)-producing carbapenem-resistant The objective of these studies was to evaluate vaborbactam pharmacokinetics (PK) and pharmacodynamics (PD) relationships for efficacy in a neutropenic mouse thigh infection model, as well as in an hollow-fiber infection model, in combination with a fixed exposure of meropenem using KPC-containing strains of For both models, the meropenem dosage regimen was designed to simulate a 2-g dose administered every eight hours (q8h) by 3-h infusion. Vaborbactam dosage regimens were designed to produce a wide range of 24-h areas under the concentration-time curves (AUCs) in the thigh infection model.

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Minocycline is currently approved in the United States for the treatment of infections caused by susceptible isolates of spp. The objective of these studies was to determine the minocycline exposures associated with an antibacterial effect against in a rat pneumonia model. Rats received minocycline doses as 30-min intravenous infusions.

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We have evaluated the activity of meropenem-vaborbactam against clinical isolates of in a neutropenic mouse thigh infection model. Data show that meropenem-vaborbactam regimens equivalent to 3-h infusions every 8 h with 2 g meropenem and 2 g vaborbactam produced bacterial killing against strains with MICs of 2 to 16 mg/liter and suggests that this combination may have utility in the treatment of infections caused by and .

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The objective of these studies was to evaluate the exposures of meropenem and vaborbactam that would produce antibacterial activity and prevent resistance development in carbapenem-resistant carbapenemase (KPC)-producing strains when tested at an inoculum of 10 CFU/ml. Thirteen isolates, three isolates, and one isolate were examined in an hollow-fiber model over 32 h. Simulated dosage regimens of 1 to 2 g of meropenem with 1 to 2 g of vaborbactam, with meropenem administered every 8 h by a 3-h infusion based on phase 1 or phase 3 patient pharmacokinetic data, were studied in the model.

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Meropenem-vaborbactam (Vabomere) is highly active against Gram-negative pathogens, especially carbapenemase (KPC)-producing, carbapenem-resistant The objective of these studies was to evaluate the efficacy of meropenem alone and in combination with vaborbactam in mouse thigh and lung infection models. Thighs or lungs of neutropenic mice were infected with KPC-producing carbapenem-resistant , with meropenem MICs ranging from ≤0.06 to 8 mg/liter in the presence of 8 mg/liter vaborbactam.

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The increasing dissemination of carbapenemases in Gram-negative bacteria has threatened the clinical usefulness of the β-lactam class of antimicrobials. A program was initiated to discover a new series of serine β-lactamase inhibitors containing a boronic acid pharmacophore, with the goal of finding a potent inhibitor of serine carbapenemase enzymes that are currently compromising the utility of the carbapenem class of antibacterials. Potential lead structures were screened in silico by modeling into the active sites of key serine β-lactamases.

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Inflammation resulting from chronic bacterial infection in the lung contributes to long-term pulmonary complications in chronic pulmonary infections such as cystic fibrosis. Aerosol administration of levofloxacin as in the form of the investigational formulation MP-376 results in higher concentrations in lung tissues that are higher than those that can be attained with oral or intravenous dosing of levofloxacin. The objective of this study was to evaluate the effect of high concentrations of levofloxacin achieved with aerosol administration of MP-376 on proinflammatory cytokine secretion by immortalized human bronchial epithelia cells in vitro.

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