Mechanisms of Resistance – Interaction of Avibactam with Class B Metallo-β-Lactamases
Antimicrob. Agents Chemother. October 2016 V.60 N.10 P.5655-5662
Martine I. Abboud, Christian Damblon, Jürgen Brem, Nicolas Smargiasso, Paola Mercuri, Bernard Gilbert, Anna M. Rydzik, Timothy D. W. Claridge, Christopher J. Schofield, and Jean-Marie Frère
aDepartment of Chemistry, University of Oxford, Oxford, United Kingdom
bLaboratoire de Chimie Biologique Structurale (CBS), Département de Chimie, Université de Liège, Liège, Belgium
cLaboratory of Mass Spectrometry, GIGA-R-CART, Université de Liège, Liège, Belgium
dCentre d’Ingénierie des Protéines, Université de Liège, Liège, Belgium
eChimie Analytique Inorganique, Département de Chimie, Université de Liège, Liège, Belgium
β-Lactamases are the most important mechanisms of resistance to the β-lactam antibacterials. There are two mechanistic classes of β-lactamases: the serine β-lactamases (SBLs) and the zinc-dependent metallo-β-lactamases (MBLs).
Avibactam, the first clinically useful non-β-lactam β-lactamase inhibitor, is a broad-spectrum SBL inhibitor, which is used in combination with a cephalosporin antibiotic (ceftazidime). There are multiple reports on the interaction of avibactam with SBLs but few such studies with MBLs.
We report biochemical and biophysical studies on the binding and reactivity of avibactam with representatives from all 3 MBL subfamilies (B1, B2, and B3). Avibactam has only limited or no activity versus MBL-mediated resistance in pathogens.
Avibactam does not inhibit MBLs and binds only weakly to most of the MBLs tested; in some cases, avibactam undergoes slow hydrolysis of one of its urea N-CO bonds followed by loss of CO2, in a process different from that observed with the SBLs studied.
The results suggest that while the evolution of MBLs that more efficiently catalyze avibactam hydrolysis should be anticipated, pursuing the development of dual-action SBL and MBL inhibitors based on the diazabicyclooctane core of avibactam may be productive.