Avibactam is a non-β-lactam β-lactamase inhibitor with a spectrum of activity that includes β-lactamase enzymes of classes A, C, and selected D examples. In this work acylation and deacylation rates were measured against the clinically important enzymes CTX-M-15, KPC-2, Enterobacter cloacae AmpC, Pseudomonas aeruginosa AmpC, OXA-10, and OXA-48. The efficiency of acylation (k2/Ki) varied across the enzyme spectrum, from 1.1 × 10(1) m(-1)s(-1) for OXA-10 to 1.0 × 10(5) for CTX-M-15. Inhibition of OXA-10 was shown to follow the covalent reversible mechanism, and the acylated OXA-10 displayed the longest residence time for deacylation, with a half-life of greater than 5 days. Across multiple enzymes, acyl enzyme stability was assessed by mass spectrometry. These inhibited enzyme forms were stable to rearrangement or hydrolysis, with the exception of KPC-2. KPC-2 displayed a slow hydrolytic route that involved fragmentation of the acyl-avibactam complex. The identity of released degradation products was investigated, and a possible mechanism for the slow deacylation from KPC-2 is proposed.
Download full-text PDF |
Source |
---|---|
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3784710 | PMC |
http://dx.doi.org/10.1074/jbc.M113.485979 | DOI Listing |
Antimicrob Agents Chemother
January 2025
Microbiology department, A Coruna University Hospital (CHUAC), Institute of Biomedical Research of A Coruna (INIBIC), A Coruna, Spain.
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 PDFAntimicrob Agents Chemother
December 2024
Louis Stokes Cleveland VA Medical Center, Cleveland, Ohio, USA.
() presents significant clinical challenges. This study evaluated the synergistic effects of a β-lactam and β-lactamase inhibitor combination against and explored the underlying mechanisms. Synergy was assessed through MIC tests and time-kill studies, and binding affinities of nine β-lactams and BLIs to eight target receptors (L,D-transpeptidases [LDT] 1-5, D,D-carboxypeptidase, penicillin-binding protein [PBP] B, and PBP-lipo) were assessed using mass spectrometry and kinetic studies.
View Article and Find Full Text PDFInt J Antimicrob Agents
January 2025
Institute of Antibiotics, Huashan Hospital, Fudan University, Shanghai, China; Key Laboratory of Clinical Pharmacology of Antibiotics, Ministry of Health, Shanghai, China. Electronic address:
Objectives: In this study, we discovered bla in ceftazidime-avibactam resistant clinical isolates of K. pneumoniae from a patient with multiple comorbidities and investigated the resistance & transfer mechanism of bla.
Methods: K.
J Glob Antimicrob Resist
December 2024
Medical and Molecular Microbiology Unit, University of Fribourg, Fribourg, Switzerland; Swiss National Center for Emerging Antibiotic Resistance, University of Fribourg, Fribourg, Switzerland. Electronic address:
Background: Several bacterial species belonging to the Gammaproteobacteria possess intrinsic class A β-lactamase genes that may represent a source of further dissemination and acquisition to other Gram-negative species. Here we characterised KSA-1 class A β-lactamase, the gene of which was identified within the chromosome of an environmental Enterobacterales species, namely Kosakonia sacchari, which was also recently identified as the progenitor of an MCR-like colistin-resistance determinant.
Methods: In silico analysis using the GenBank database identified a class A β-lactamase gene within the chromosome of K.
Eur J Clin Microbiol Infect Dis
October 2024
Center of Infectious Diseases, West China Hospital, Sichuan University, Chengdu, China.
A novel KPC variant, KPC-84, identified in a Klebsiella pneumoniae isolate from China, exhibits a threonine (T) to proline (P) amino acid substitution at Ambler position 243(T243P), altering from the KPC-2 sequence. Cloning and expression of bla in Escherichia coli, with subsequent MIC assessments, revealed increased resistance to ceftazidime-avibactam and significantly reduced carbapenemase activity compared to KPC-2. Kinetic measurements showed that KPC-84 exhibited sligthly higher hydrolysis of ceftazidime and reduced affinity for avibactam compared to KPC-2.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!