Carbapenemases: molecular diversity and clinical consequences.
Carbapenemases are beta-lactamases that hydrolyze most beta-lactams including carbapenems. Carbapenemases are classified in four molecular classes; those belonging to class A are the chromosomally-encoded and clavulanic acid-inhibited IMI, NMC-A and SME, identified in Enterobacter cloacae and Serratia marcescens; the plasmid-encoded KPC enzymes identified in Enterobacteriaceae (and rarely in Pseudomonas aeruginosa); and the GES-type enzymes identified in Enterobacteriaceae and P. aeruginosa. The class B enzymes are the most clinically-significant carbapenemases; they are metallo-beta-lactamases, mostly of the IMP and the VIM series. They have been reported worldwide and their genes are plasmid- and integron-located, hydrolyzing all beta-lactams with the exception of aztreonam. One single plasmid-mediated AmpC beta-lactamase, CMY-10, identified in an Enterobacter aerogenes isolate, has been shown to be a cephaslosporinase with some carbapenemase properties. Finally, the class D carbapenemases are being increasingly reported, mostly in Acinetobacter baumannii, and they compromise the efficacy of imipenem and meropenem significantly.
Poirel
Laurent
L
Université Paris XI, Service de Bactériologie-Virologie, Hôpital de Bicêtre, Assistance Punblique/Hôpitaux de Paris, Faculté de Médecine Paris-Sud, 94275 K.-Bicêtre, France. laurent.poirel@bct.aphp.fr
Pitout
Johann D
JD
Nordmann
Patrice
P
D001426:Bacterial Proteins / Q000145:classification* / Q000235:genetics / Q000378:metabolism; D015780:Carbapenems / Q000378:metabolism / Q000494:pharmacology*; D024881:Drug Resistance, Bacterial; D006090:Gram-Negative Bacteria / Q000201:enzymology / Q000235:genetics; D016905:Gram-Negative Bacterial Infections / Q000382:microbiology; D006801:Humans; D001618:beta-Lactamases / Q000145:classification* / Q000235:genetics / Q000378:metabolism
D001426:Bacterial Proteins; D015780:Carbapenems; D001618:beta-Lactamases; C063912:carbapenemase