Beta-lactamase (Class A and Class B) (Class A/B BLs)

Beta-lactamases are bacterial enzymes that confer resistance to beta-lactam antibiotics by catalyzing the hydrolysis of the antibiotic's core ring structure. According to the Ambler classification system, Class A enzymes are serine-beta-lactamases that utilize a covalent serine-acyl intermediate, while Class B enzymes are metallo-beta-lactamases (MBLs) that require zinc ions for their catalytic mechanism [1][2]. These enzymes are primary drivers of multi-drug resistance in Gram-negative pathogens, such as Klebsiella pneumoniae and Pseudomonas aeruginosa, often leading to severe healthcare-associated infections [3]. Therapeutic strategies involve combining beta-lactam antibiotics with beta-lactamase inhibitors (BLIs) to restore the antibiotic's efficacy [4]. While traditional BLIs primarily target Class A enzymes, the emergence of Class B MBLs has led to the development of next-generation inhibitors like taniborbactam, which are designed to inhibit both Class A and Class B enzymes simultaneously [5]. The presence of these enzymes is often detected through molecular techniques like PCR or phenotypic assays like the Carba NP test to guide clinical decision-making. Effective inhibition of both classes is a major goal in modern drug development to combat carbapenem-resistant Enterobacteriaceae (CRE).

Other names

Serine beta-lactamaseMetallo-beta-lactamasePenicillinaseCephalosporinaseCarbapenemaseAmbler Class A beta-lactamaseAmbler Class B beta-lactamase

Inhibition of beta-lactamase activity through covalent binding to the active-site serine (Class A) or coordination/displacement of catalytic zinc ions (Class B) to prevent the hydrolysis of beta-lactam antibiotics.