Bacterial serine beta-lactamase (SBL)

Bacterial serine beta-lactamases are a diverse group of enzymes produced by bacteria to hydrolyze the beta-lactam ring of antibiotics, such as penicillins, cephalosporins, and carbapenems, thereby rendering them inactive (Bush & Jacoby, 2010). These enzymes are categorized into Ambler classes A, C, and D based on their amino acid sequences and utilize a conserved serine residue in their active site to facilitate the hydrolytic reaction (Ambler, 1980). They represent a primary mechanism of antibiotic resistance in clinically significant Gram-negative pathogens like Klebsiella pneumoniae, Escherichia coli, and Pseudomonas aeruginosa (StatPearls, "Beta Lactamase Inhibitors"). In clinical practice, these enzymes are targeted by beta-lactamase inhibitors, such as clavulanic acid or avibactam, which are often administered in combination with a beta-lactam antibiotic to protect the latter from degradation (Drawz & Bonomo, 2010). The emergence and global spread of extended-spectrum beta-lactamases (ESBLs) and serine carbapenemases (e.g., KPC) have significantly limited treatment options for serious hospital-acquired infections (CDC, "Antibiotic Resistance Threats in the United States"). Understanding the structural and functional diversity of these enzymes is critical for the development of next-generation inhibitors capable of overcoming evolving bacterial resistance mechanisms (Bush, 2018).

Other names

Serine-based beta-lactamaseAmbler Class A beta-lactamaseAmbler Class C beta-lactamaseAmbler Class D beta-lactamasePenicillinaseCephalosporinaseExtended-spectrum beta-lactamaseSerine carbapenemase

Inhibition of the serine beta-lactamase enzyme through covalent or non-covalent binding to the active site serine residue, preventing the degradation of co-administered beta-lactam antibiotics and restoring their antibacterial efficacy (Drawz & Bonomo, 2010; Bush, 2018).