Carbapenemase OXA-48 and its variants pose a serious threat to the development of effective treatments for bacterial infections. OXA-48-producing Enterobacterales are the most prevalent carbapenemase-producing bacteria in large parts of the world. Although these bacteria exhibit low-level carbapenem resistance , the infections they cause are challenging to treat with conventional therapies, owing to their spread and complex detection in clinical settings.
View Article and Find Full Text PDFBiomed Pharmacother
December 2024
Introduction: The rise in multidrug-resistant bacteria challenges clinical microbiology. Tigecycline, eravacycline, and omadacycline show promise against carbapenem-resistant Enterobacterales and Acinetobacter baumannii. This study evaluates their activity and resistance mechanisms.
View Article and Find Full Text PDFAntimicrob Agents Chemother
December 2024
carbapenemase (KPC) variants selected during ceftazidime/avibactam treatment usually develop susceptibility to carbapenems and carbapenem/β-lactamase inhibitors, such as imipenem and imipenem/relebactam. We analyzed imipenem and imipenem/relebactam single-step mutant frequencies, resistance development trajectories and differentially selected resistance mechanisms using two representative isolates that had developed ceftazidime/avibactam resistance during therapy (ST512/KPC-31 and ST258/KPC-35). Mutant frequencies and mutant prevention concentrations were measured in Mueller-Hinton agar plates containing incremental concentrations of imipenem or imipenem/relebactam.
View Article and Find Full Text PDFWe describe the emergence of resistance to ceftazidime/avibactam via modification of AmpC in a clinical isolate during therapy with this combination. Paired ceftazidime/avibactam-susceptible/resistant isolates were obtained before and during ceftazidime/avibactam treatment. Whole genome sequencing revealed a differential mutation in AmpC (R148W) in the ceftazidime/avibactam-resistant isolate.
View Article and Find Full Text PDFIntroduction: Linezolid is a broadly used antibiotic to treat complicated infections caused by gram-positive bacteria. Therapeutic drug monitoring of linezolid concentrations is recommended to maximise its efficacy and safety, mainly haematological toxicity. Different pharmacokinetic/pharmacodynamic targets have been proposed to improve linezolid exposure: the ratio of the area under the concentration-time curve during a 24-hour period to minimum inhibitory concentration (MIC) between 80 and 120; percentage of time that the drug concentration remains above the MIC during a dosing interval greater than 85% and the trough concentration between 2 and 7 mg/L.
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