Oxacillinase-48 β-lactamase (OXA-48) (OXA-48)

Oxacillinase-48 β-lactamase (OXA-48) is a prominent Ambler Class D carbapenemase that mediates high-level resistance to penicillins and low-level resistance to carbapenems in Gram-negative bacteria [1, 6]. Primarily found in Enterobacteriaceae such as Klebsiella pneumoniae and Escherichia coli, it functions as a serine-based enzyme that hydrolyzes the β-lactam ring of antibiotics, thereby neutralizing their antibacterial activity [5, 8]. The enzyme is particularly clinically significant due to its rapid dissemination via highly mobile IncL plasmids and its ability to evade detection in routine phenotypic susceptibility tests [1, 6, 11]. While it does not naturally hydrolyze expanded-spectrum cephalosporins, it is frequently co-produced with extended-spectrum β-lactamases (ESBLs), leading to multidrug-resistant phenotypes [1, 11]. Therapeutic management of OXA-48-producing infections often relies on the use of next-generation β-lactamase inhibitors like avibactam, which covalently inactivates the enzyme to restore the efficacy of partner antibiotics [2, 4, 6]. The global spread of OXA-48 represents a major public health challenge, necessitating robust molecular surveillance and the development of novel inhibitory agents [6, 10].

Other names

OXA-48 carbapenemaseClass D carbapenemaseCarbapenem-hydrolyzing class D beta-lactamaseCHDLBeta-lactamase OXA-48OXA-48-like carbapenemaseOXA-48-like enzyme

Covalent inhibition of the active-site serine residue (Ser-70) to prevent antibiotic hydrolysis [8, 9]