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

CTX-M-15 serine β-lactamase is a prominent member of the Class A extended-spectrum beta-lactamases (ESBLs) and is currently the most prevalent CTX-M variant worldwide [1.2.1, 1.3.1]. It is primarily produced by Gram-negative bacteria, such as Escherichia coli and Klebsiella pneumoniae, where it confers high-level resistance to third-generation cephalosporins like cefotaxime and ceftriaxone [1.2.2, 1.4.1]. The enzyme operates as a serine hydrolase (EC 3.5.2.6), utilizing an active-site serine residue to nucleophilically attack and break the four-membered beta-lactam ring of antibiotics, thereby inactivating them [1.2.3, 1.3.3]. This resistance mechanism significantly limits treatment options for common infections, including urinary tract infections and sepsis, leading to increased morbidity and mortality [1.3.1, 1.5.1]. CTX-M-15 is frequently encoded on highly mobile plasmids, facilitating its rapid global dissemination through horizontal gene transfer [1.2.2, 1.4.2]. To overcome this resistance, clinical practice often employs combinations of beta-lactam antibiotics with beta-lactamase inhibitors such as tazobactam, avibactam, or vaborbactam [1.1.1, 1.2.3]. These inhibitors bind to the enzyme's active site, preventing the degradation of the co-administered antibiotic and restoring its therapeutic efficacy [1.2.3, 1.2.5]. The emergence of mutations within the enzyme or its overproduction continues to pose a challenge to the long-term effectiveness of these inhibitor combinations [1.2.3, 1.2.4].

Other names

Cefotaximase-Munich 15Extended-spectrum beta-lactamase CTX-M-15ESBL CTX-M-15blaCTX-M-15

Beta-lactamase inhibitors target the enzyme by forming a stable acyl-enzyme complex with the active-site serine or through reversible non-covalent binding, thereby preventing the hydrolysis of co-administered beta-lactam antibiotics [1.2.3, 1.2.5].