Class C beta-lactamase MOX-1 (MOX-1)

Class C beta-lactamase MOX-1 is a plasmid-mediated enzyme belonging to the AmpC family, originally identified in Klebsiella pneumoniae and derived from the chromosomal genes of Aeromonas species [1][2]. It functions as a serine hydrolase that efficiently degrades a wide range of beta-lactam antibiotics, including penicillins and extended-spectrum cephalosporins such as ceftazidime [3]. A defining characteristic of MOX-1 is its ability to confer resistance to cephamycins like cefoxitin, which are typically stable against Class A beta-lactamases [1]. As a plasmid-encoded enzyme, it is often expressed constitutively and can be rapidly disseminated among Gram-negative pathogens, complicating the treatment of hospital-acquired infections [2]. While resistant to classical inhibitors like clavulanic acid, MOX-1 is susceptible to modern non-beta-lactam beta-lactamase inhibitors such as avibactam, which are used in combination therapy to restore the efficacy of partner antibiotics [3].

Other names

MOX-1 beta-lactamasePlasmid-mediated AmpC beta-lactamase MOX-1CMY-1-like beta-lactamase

Inhibition of the enzyme's active site serine residue by beta-lactamase inhibitors, which forms a stable complex that prevents the hydrolysis of co-administered beta-lactam antibiotics [1][3].