Metallo-beta-lactamase IMP-type enzyme (IMP-type MBL)

Metallo-beta-lactamase IMP-type enzymes are zinc-dependent beta-lactamases classified within subclass B1 of the metallo-beta-lactamase (MBL) family. Originally identified in Japan in the early 1990s, these enzymes confer broad resistance to nearly all beta-lactam antibiotics—including carbapenems, cephalosporins, and penicillins—by catalyzing hydrolysis of the beta-lactam ring through a di-zinc mechanism[1][2][3][4][6]. Clinically, IMP-type MBLs are major drivers of multidrug resistance among Gram-negative bacteria, particularly Pseudomonas aeruginosa, Enterobacterales, and Acinetobacter species. Over 80 genetic variants (e.g., IMP-1, IMP-27) have been described, with ongoing evolution to enhance substrate affinities and metal-ion utilization[3]. The genes encoding these enzymes are often located on integrons, facilitating horizontal transfer and rapid global dissemination. There are no clinically available inhibitors, and the rise of IMP-type MBL-producing bacteria is a critical public health concern due to severely limited effective antimicrobials[7].

Other names

IMP-type metallo-beta-lactamaseIMP-type MBLImipenemase (in some clinical contexts)Class B1 metallo-beta-lactamase (subset)IMP enzyme

Hydrolyzes the beta-lactam ring of beta-lactam antibiotics via a zinc-dependent nucleophilic attack, deactivating antibiotic activity[1][4][5]. Renders bacteria resistant to a wide range of beta-lactam antibiotics, including carbapenems, through enzymatic degradation[2][3][4].