Karbapenemázy

Karbapenemázy (carbapenemases) are beta-lactamase enzymes that hydrolyze carbapenem antibiotics, such as imipenem and meropenem, enabling high-level resistance to many beta-lactams in Gram-negative bacteria and representing a major mechanism of carbapenem resistance.

They are classified by Ambler as class A serine carbapenemases (for example KPC), class B metallo-beta-lactamases (NDM, VIM, IMP, and others), and class D oxacillinase carbapenemases (OXA-48-like). Serine carbapenemases use a serine residue; metallo-beta-lactamases require zinc. Many carbapenemases are carried on mobile genetic elements such as plasmids, promoting spread between species.

Geographically widespread, karbapenemázy are found in Enterobacterales (notably Klebsiella pneumoniae and Escherichia coli) and in nonfermenters such as Pseudomonas aeruginosa and Acinetobacter baumannii, contributing to the emergence of carbapenem-resistant Enterobacterales (CRE).

Detection relies on phenotypic tests like the Carba NP test or the carbapenem inactivation method, and molecular assays for bla genes (e.g., blaKPC, blaNDM, blaVIM, blaIMP, blaOXA-48). Surveillance and rapid diagnostics are key to infection control and treatment decisions.

Treatment is challenging and depends on the enzyme type and resistance profile. Some serine carbapenemases are susceptible to certain beta-lactamase inhibitors (for example, ceftazidime-avibactam, meropenem-vaborbactam, imipenem-relebactam). Metallo-beta-lactamase producers may require aztreonam in combination with inhibitors or other non-beta-lactam agents; options continue to evolve with ongoing research.