Increasing resistance to cephalosporins among Gram-negative bacterial pathogens, especially among hospital-acquired infections, results in part from the production of β-lactamase enzymes that deactivate these antibiotics. While the co-administration of a β-lactamase inhibitor can restore antibacterial activity to the cephalosporin, previously approved β-lactamase inhibitors such as tazobactam and clavulanic acid do not inhibit important classes of β-lactamases, including Klebsiella pneumoniaecarbapenemases (KPCs), New Delhi metallo-β-lactamase 1 (NDM-1), and AmpC-type β-lactamases. Whilst avibactam inhibits class A (KPCs, CTX-M, TEM, SHV), class C (AmpC), and some class D serine β-lactamases (such as OXA-23, OXA-48), it has been reported to be a poor substrate/weak inhibitor of class B metallo-β-lactamases, such as VIM-2, VIM-4, SPM-1, BcII, NDM-1, Fez-1.[6]
For infections sustained by metallo-β-lactamases producing bacteria, a therapeutic strategy consists in administering avibactam as companion drug administered alongside aztreonam. In fact, although in theory aztreonam is not hydrolyzed by metallo-β-lactamases, many metallo-β-Lactamases-producing strains co-produce enzymes that could hydrolyze aztreonam (e.g. AmpC, ESBL), therefore avibactam is given to protect aztreonam exploiting its robust β-lactamases inhibition.[7] Avibactam is available in a combination with aztreonam (aztreonam/avibactam) and (Meropenem/avibactum) by the brand name Meropran-AV (Pranada Biopharma).
