Class C serine beta-lactamase (AmpC)

Class C serine beta-lactamases, frequently referred to as AmpC enzymes, are bacterial hydrolases that play a critical role in antimicrobial resistance among Gram-negative pathogens such as Enterobacterales and Pseudomonas aeruginosa (StatPearls: NBK554446). These enzymes are characterized by their ability to hydrolyze a broad spectrum of beta-lactam antibiotics, including penicillins, most cephalosporins, and monobactams, while remaining largely unaffected by traditional inhibitors like clavulanic acid or sulbactam (PubMed: 19150859). They are encoded either on the chromosomes of various bacteria or on mobile plasmids, facilitating their rapid spread across different species. The expression of AmpC can be induced by the presence of certain antibiotics or become constitutively high through mutations in regulatory genes, a state known as derepression, which often leads to clinical failure during therapy (PubMed: 9145860). To combat these enzymes, novel non-beta-lactam inhibitors such as diazabicyclooctanes (e.g., avibactam) and boronic acid derivatives (e.g., vaborbactam) have been developed and are used in combination with existing antibiotics to restore their activity against resistant strains (PubMed: 26248265).

Other names

AmpC beta-lactamaseClass C beta-lactamaseCephalosporinaseAmbler Class C beta-lactamaseGroup 1 beta-lactamase

Inhibition of the catalytic serine residue within the enzyme active site, typically through covalent binding by diazabicyclooctanes or boronic acid derivatives, which prevents the enzyme from hydrolyzing the beta-lactam ring of antibiotics (PubMed: 26248265).