Beta-lactamase CTX-M-15 (CTX-M-15)

Beta-lactamase CTX-M-15 is a prominent member of the Class A extended-spectrum beta-lactamases (ESBLs), characterized by its potent ability to hydrolyze cefotaxime and other oxyimino-cephalosporins [1, 10, 13]. This enzyme is a critical factor in the development of antimicrobial resistance among Gram-negative pathogens, most notably Escherichia coli and Klebsiella pneumoniae [5, 6, 8]. It functions by cleaving the amide bond within the beta-lactam ring of antibiotics, effectively neutralizing them before they can inhibit bacterial cell wall synthesis [1, 4, 14]. The gene encoding CTX-M-15, blaCTX-M-15, is frequently located on highly mobilizable plasmids, which has facilitated its rapid global dissemination across both clinical and community environments [5, 8, 13]. Infections involving CTX-M-15-producing bacteria, such as complicated urinary tract infections and bacteremia, are associated with increased morbidity and limited treatment options [6, 7, 8]. To combat this resistance, clinicians often employ combinations of beta-lactam antibiotics with beta-lactamase inhibitors like tazobactam or avibactam, which bind to and inactivate the enzyme [2, 10, 13]. However, the ongoing evolution of CTX-M variants and the emergence of co-resistance to other antibiotic classes present significant therapeutic challenges [10, 13, 14]. Understanding the structural and functional properties of CTX-M-15 remains essential for the development of next-generation inhibitors and effective infection control strategies [2, 4].

Other names

Cefotaximase-Munich 15 [8]Extended-spectrum beta-lactamase CTX-M-15 [5]blaCTX-M-15 [1, 2]CTX-M-15 type beta-lactamase [6]

Beta-lactamase CTX-M-15 acts by hydrolyzing the amide bond of the beta-lactam ring in antibiotics, such as penicillins and cephalosporins, rendering them inactive and unable to inhibit bacterial cell wall synthesis [1, 4, 14]. Therapeutic inhibitors, such as tazobactam and avibactam, counteract this by forming a stable, covalent acyl-enzyme complex with the active site serine residue (Ser70), thereby preventing the enzyme from processing antibiotic substrates [2, 10].