Transcending the challenge of evolving resistance mechanisms in through β-lactam-enhancer-mechanism-based cefepime/zidebactam.

Compared to other genera of Gram-negative pathogens, is adept in acquiring complex non-enzymatic and enzymatic resistance mechanisms thus remaining a challenge to even novel antibiotics including recently developed β-lactam and β-lactamase inhibitor combinations. This study shows that the novel β-lactam enhancer approach enables cefepime/zidebactam to overcome both non-enzymatic and enzymatic resistance mechanisms associated with a challenging panel of . This study highlights that the β-lactam enhancer mechanism is a promising alternative to the conventional β-lactam/β-lactamase inhibitor approach in combating ever-evolving MDR .

β-Lactam Resistance in ESKAPE Pathogens Mediated Through Modifications in Penicillin-Binding Proteins: An Overview.

Bacteria acquire β-lactam resistance through a multitude of mechanisms among which production of β-lactamases (enzymes that hydrolyze β-lactams) is the most common, especially in Gram-negatives. Structural changes in the high-molecular-weight, essential penicillin-binding proteins (PBPs) are widespread in Gram-positives and increasingly reported in Gram-negatives. PBP-mediated resistance is largely achieved by accumulation of mutation(s) resulting in reduced binding affinities of β-lactams.

In vitro evolution of cefepime/zidebactam (WCK 5222) resistance in Pseudomonas aeruginosa: dynamics, mechanisms, fitness trade-off and impact on in vivo efficacy.

Objectives: To study the dynamics, mechanisms and fitness cost of resistance selection to cefepime, zidebactam and cefepime/zidebactam in Pseudomonas aeruginosa.

Methods: WT P. aeruginosa PAO1 and its ΔmutS derivative (PAOMS) were exposed to stepwise increasing concentrations of cefepime, zidebactam and cefepime/zidebactam.

In vitro activity of cefepime/zidebactam (WCK 5222) against recent Gram-negative isolates collected from high resistance settings of Greek hospitals.

Cefepime/zidebactam is in clinical development for the treatment of carbapenem-resistant Gram-negative infections. MICs of cefepime/zidebactam (1:1) and comparators against Enterobacterales (n = 563), Pseudomonas (n = 172) and Acinetobacter baumannii (n =181) collected from 15 Greek hospitals (2014-2018) were determined by reference broth microdilution method. The isolates exhibited high carbapenem resistance rates [(Enterobacterales (75%), Pseudomonas (75%) and A.

Efficacy and Safety of a Novel Broad-Spectrum Anti-MRSA Agent Levonadifloxacin Compared with Linezolid for Acute Bacterial Skin and Skin Structure Infections: A Phase 3, Openlabel, Randomized Study.

Background: Levonadifloxacin is a novel broad-spectrum anti-MRSA agents belonging to the benzoquinolizine subclass of quinolone. It is developed for oral or intravenous administration for the treatment of infections caused by Gram-positive organisms including methicillin-resistant Staphylococcus aureus (MRSA).

Objectives: To establish the non-inferiority of levonadifloxacin compared with linezolid for the treatment of acute bacterial skin and skin structure infections (ABSSSI) and to compare the safety of the two antimicrobials.

Immunomodulatory dose of clindamycin in combination with ceftriaxone improves survival and prevents organ damage in murine polymicrobial sepsis.

Sepsis is a life-threatening organ dysfunction resulting from inflammatory responses instigated by toxins secreted by bacteria. Immunomodulatory effect of clindamycin is earlier reported in a murine lipopolysaccharide (LPS)-induced sepsis model. There are no studies demonstrating the immunomodulatory effect of clindamycin in combination with ceftriaxone in a clinically relevant murine polymicrobial sepsis model induced by cecal ligation and puncture (CLP).

Immunomodulatory Effect of Doxycycline Ameliorates Systemic and Pulmonary Inflammation in a Murine Polymicrobial Sepsis Model.

Acute lung injury is an inflammatory condition developed after severe sepsis in response to excessive secretion of pro-inflammatory cytokines. Doxycycline is widely reported to possess immunomodulatory activity through inhibition of various inflammatory pathways. Considering the broad spectrum of anti-inflammatory activity, protective effect of doxycycline was evaluated in clinically relevant murine polymicrobial sepsis model induced by caecal ligation and puncture (CLP).

Levonadifloxacin, a Novel Broad-Spectrum Anti-MRSA Benzoquinolizine Quinolone Agent: Review of Current Evidence.

Levonadifloxacin and its prodrug alalevonadifloxacin are novel broad-spectrum anti-MRSA agents belonging to the benzoquinolizine subclass of quinolone, formulated for intravenous and oral administration, respectively. Various in vitro and in vivo studies have established their antimicrobial spectrum against clinically significant Gram-positive, Gram-negative, atypical, and anaerobic pathogens. The potent activity of levonadifloxacin against MRSA, quinolone-resistant , and hetero-vancomycin-intermediate strains is an outcome of its well-differentiated mechanism of action involving preferential targeting to DNA gyrase.

Pharmacokinetic/Pharmacodynamic Targets of Levonadifloxacin against Staphylococcus aureus in a Neutropenic Murine Lung Infection Model.

Levonadifloxacin is a novel benzoquinolizine subclass of fluoroquinolone, active against quinolone-resistant A phase 3 trial for levonadifloxacin and its oral prodrug was recently completed. The present study identified area under the concentration-time curve for the free, unbound fraction of a drug divided by the MIC (AUC/MIC) as an efficacy determinant for levonadifloxacin in a neutropenic murine lung infection model. Mean plasma AUC/MIC requirement for static and 1 log kill effects against 9 were 8.

and Activities of β-Lactams in Combination with the Novel β-Lactam Enhancers Zidebactam and WCK 5153 against Multidrug-Resistant Metallo-β-Lactamase-Producing Klebsiella pneumoniae.

Zidebactam and WCK 5153 are novel bicyclo-acyl hydrazide (BCH) agents that have previously been shown to act as β-lactam enhancer (BLE) antibiotics in and The objectives of this work were to identify the molecular targets of these BCHs in and to investigate their potential BLE activity for cefepime and aztreonam against metallo-β-lactamase (MBL)-producing strains and Penicillin binding protein (PBP) binding profiles were determined by Bocillin FL assay, and 50% inhibitory concentrations (ICs) were determined using ImageQuant TL software. MICs and kill kinetics for zidebactam, WCK 5153, and cefepime or aztreonam, alone and in combination, were determined against clinical isolates producing MBLs VIM-1 or NDM-1 (plus ESBLs and class C β-lactamases) to assess the enhancer effect of BCH compounds in conjunction with β-lactams. Additionally, murine systemic and thigh infection studies were conducted to evaluate BLE effects Zidebactam and WCK 5153 showed specific, high PBP2 affinity in The MICs of BLEs were >64 μg/ml for all MBL-producing strains.

The Novel β-Lactam Enhancer Zidebactam Augments the Pharmacodynamic Activity of Cefepime in a Neutropenic Mouse Lung Infection Model.

WCK 5222 is a combination of cefepime and the high-affinity PBP2-binding β-lactam enhancer zidebactam. The cefepime-zidebactam combination is active against multidrug-resistant Gram-negative bacteria, including carbapenemase-expressing The mechanism of action of the combination involves concurrent multiple penicillin binding protein inhibition, leading to the enhanced bactericidal action of cefepime. The aim of the present study was to assess the impact of the zidebactam-mediated enhanced bactericidal action in modulating the percentage of the time that the free drug concentration remains above the MIC (percent >MIC) for cefepime required for the killing of Cefepime and cefepime-zidebactam MICs were comparable and ranged from 2 to 16 mg/liter for the strains ( = 5) employed in the study.

Azithromycin in Combination with Ceftriaxone Reduces Systemic Inflammation and Provides Survival Benefit in a Murine Model of Polymicrobial Sepsis.

Sepsis is a life-threatening systemic inflammatory condition triggered as a result of an excessive host immune response to infection. In the past, immunomodulators have demonstrated a protective effect in sepsis. Azithromycin (a macrolide antibiotic) has immunomodulatory activity and was therefore evaluated in combination with ceftriaxone in a clinically relevant murine model of sepsis induced by cecal ligation and puncture (CLP).