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Publication Abstract from PubMed

Avibactam is a novel non-beta-lactam beta-lactamase inhibitor that inhibits a wide range of beta-lactamases. These include class A, class C and some class D enzymes, which erode the activity of beta-lactam drugs in multi-drug-resistant pathogens like Pseudomonas aeruginosa and Enterobacteriaceae. Avibactam is currently in clinical development in combination with the beta-lactam antibiotics ceftazidime, ceftaroline fosamil and aztreonam. Avibactam has the potential to be the first beta-lactamase inhibitor that could provide activity against class C-mediated resistance, which represents a growing concern in both hospital- and community-acquired infections. Avibactam has an unusual mechanism of action: it is a covalent inhibitor that acts via ring-opening but, in contrast to other currently used beta-lactamase inhibitors, this reaction is reversible. Here we present a high resolution structure of avibactam bound to a class C beta-lactamase, AmpC, from P. aeruginosa that provided insight into the mechanism of both acylation and recyclization in this enzyme class and highlighted the differences observed between class A and class C inhibition. Furthermore, variants resistant to avibactam were isolated that identified the residues that are important for inhibition. Finally, the structural information was used to predict effective inhibition by sequence analysis and functional studies of class C beta-lactamases from a large and diverse set of contemporary clinical isolates (P. aeruginosa and several Enterobacteriaceae spp.) obtained from recent infections to understand any pre-existing variability in the binding pocket that could affect inhibition by avibactam.

Avibactam and class C beta-lactamases: mechanism of inhibition, conservation of binding pocket and implications for resistance.,Lahiri SD, Johnstone M, Ross PL, McLaughlin R, Olivier NB, Alm RA Antimicrob Agents Chemother. 2014 Jul 14. pii: AAC.03057-14. PMID:25022578^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.