Sulfhydryl variable 12 beta-lactamase (SHV-12) (SHV-12)

SHV-12 is a clinically significant extended-spectrum beta-lactamase (ESBL) belonging to the Ambler Class A group of serine beta-lactamases [2, 6]. It is a variant of the SHV-1 enzyme, typically evolving from SHV-5 through specific amino acid substitutions, such as Gln35Leu, Ser238, and Lys240, which expand its hydrolytic spectrum to include third- and fourth-generation cephalosporins and monobactams like aztreonam [1, 4]. Primarily found in Enterobacteriaceae such as Klebsiella pneumoniae and Escherichia coli, SHV-12 is often encoded on highly mobile plasmids, facilitating its rapid global dissemination [3, 5]. As a major driver of antimicrobial resistance, it poses a severe challenge in hospital settings by rendering standard beta-lactam therapies ineffective [10, 11]. Therapeutic strategies involve the use of beta-lactamase inhibitors like clavulanic acid or newer agents like avibactam in combination with antibiotics to restore their activity [10, 12]. The enzyme's ability to hydrolyze a broad range of antibiotics while remaining susceptible to certain inhibitors makes it a critical focal point for both diagnostic testing and the development of novel antimicrobial combinations [6, 9].

Other names

blaSHV-12SHV-12 ESBLClass A beta-lactamase SHV-12Extended-spectrum beta-lactamase SHV-12

Beta-lactamase inhibitors target SHV-12 by binding to its active site, often forming a stable covalent acyl-enzyme intermediate that prevents the enzyme from hydrolyzing beta-lactam antibiotics, thereby restoring the efficacy of the co-administered antibiotic [6, 10, 12].