Beta-lactamase CMY-2 (CMY-2)

CMY-2 is a plasmid-mediated Ambler Class C (AmpC-type) serine beta-lactamase that confers high-level resistance to a broad spectrum of beta-lactam antibiotics, including penicillins, cephamycins, and extended-spectrum cephalosporins. It is one of the most prevalent and clinically significant plasmid-encoded AmpC enzymes, frequently identified in Enterobacteriaceae such as Escherichia coli and Salmonella species. The enzyme utilizes a catalytic serine residue to nucleophilically attack and hydrolyze the four-membered beta-lactam ring, effectively neutralizing the antibiotic before it can inhibit bacterial cell wall synthesis. CMY-2 is notably resistant to first-generation beta-lactamase inhibitors like clavulanic acid and sulbactam, which necessitates the use of newer agents such as avibactam or vaborbactam in clinical practice. Its widespread dissemination via mobile genetic elements represents a major challenge in the management of multidrug-resistant bacterial infections.

Other names

CMY-2 serine beta-lactamaseCMY-2 cephalosporinasePlasmid-mediated AmpC beta-lactamase CMY-2Ambler class C beta-lactamase CMY-2blaCMY-2

CMY-2 is a serine-dependent enzyme that catalyzes the hydrolysis of the beta-lactam ring in antibiotics such as penicillins and cephalosporins, rendering them inactive. Therapeutic inhibitors like avibactam or vaborbactam work by covalently binding to the active-site serine or acting as transition-state analogs to block the enzyme's catalytic activity, thereby restoring the efficacy of co-administered beta-lactam antibiotics.