ceftazidime
Mechanisms of ResistanceStructural Insights into Inhibition of the Acinetobacter-Derived Cephalosporinase ADC-7 by Ceftazidime and Its Boronic Acid Transition State AnalogExtended-spectrum class C β-lactamases have evolved to rapidly inactivate expanded-spectrum cephalosporins, a class of antibiotics designed to be resistant to hydrolysis by β-lactamase enzymes. To better understand the mechanism by which Acinetobacter-derived cephalosporinase-...
Editor's Pick Mechanisms of ResistanceAdding Insult to Injury: Mechanistic Basis for How AmpC Mutations Allow Pseudomonas aeruginosa To Accelerate Cephalosporin Hydrolysis and Evade AvibactamPseudomonas aeruginosa is a leading cause of nosocomial infections worldwide and notorious for its broad-spectrum resistance to antibiotics. A key mechanism that provides extensive resistance to β-lactam antibiotics is the inducible expression of AmpC β-lactamase. Recently, a number of clinical isolates expressing mutated forms of AmpC have been found to be clinically...
Mechanisms of ResistanceStructural Basis of Reduced Susceptibility to Ceftazidime-Avibactam and Cefiderocol in Enterobacter cloacae Due to AmpC R2 Loop DeletionCeftazidime-avibactam and cefiderocol are two of the latest generation β-lactam agents that possess expanded activity against highly drug-resistant bacteria, including carbapenem-resistant Enterobacterales. Here, we show that structural changes in AmpC β-lactamases can confer reduced susceptibility to both agents. A multidrug-resistant Enterobacter cloacae...
Mechanisms of ResistanceCeftazidime-Avibactam Resistance Mediated by the N346Y Substitution in Various AmpC β-LactamasesChromosomal and plasmid-borne AmpC cephalosporinases are a major resistance mechanism to β-lactams in Enterobacteriaceae and Pseudomonas aeruginosa. The new β-lactamase inhibitor avibactam effectively inhibits class C enzymes and can fully restore ceftazidime susceptibility. The conserved amino acid residue Asn346 of AmpC cephalosporinases directly...
PharmacologyActivity of Antibiotics against Pseudomonas aeruginosa in an In Vitro Model of Biofilms in the Context of Cystic Fibrosis: Influence of the Culture MediumPseudomonas aeruginosa is a major cause of respiratory biofilm-related infections in patients with cystic fibrosis. We developed an in vitro pharmacodynamic model to study the activity of antipseudomonal antibiotics against PAO1 biofilms grown in artificial sputum medium with agar [ASM(+)] versus that against biofilms grown in Trypticase soy broth...
Mechanisms of ResistanceMutation-Driven Evolution of Pseudomonas aeruginosa in the Presence of either Ceftazidime or Ceftazidime-AvibactamCeftazidime-avibactam is a combination of β-lactam/β-lactamase inhibitor, the use of which is restricted to some clinical cases, including cystic fibrosis patients infected with multidrug-resistant Pseudomonas aeruginosa, in which mutation is the main driver of resistance. This study aims to predict the mechanisms of mutation-driven resistance that are selected for...
- Clinical Therapeuticsβ-Lactam Dosage Regimens in Septic Patients with Augmented Renal Clearance...
Augmented renal clearance is commonly observed in septic patients and may result in insufficient β-lactam serum concentrations. The aims of this study were to evaluate potential correlations between drug concentrations or total body clearance of β-lactam antibiotics and measured creatinine clearance and to quantify the need for drug dosage adjustments in septic patients with different levels of augmented renal clearance.
- Mechanisms of ResistanceCombination of Amino Acid Substitutions Leading to CTX-M-15-Mediated Resistance to the Ceftazidime-Avibactam Combination
Single amino acid substitutions in the Ω loop of KPC β-lactamases are known to lead to resistance to the ceftazidime-avibactam combination. Here, we investigate this mechanism of resistance in CTX-M enzymes, which are the most widely spread extended-spectrum β-lactamases worldwide.
- Mechanisms of ResistanceDefining Substrate Specificity in the CTX-M Family: the Role of Asp240 in Ceftazidime Hydrolysis