Dissemination of carbapenemase-producing Enterobacteriaceae

During the last decade, Gram-negative clinical isolates, including Enterobacteriaceae, Pseudomonas spp. and Acinetobacter spp. with decreased susceptibility to carbapenems, have been increasingly reported in Europe. Carbapenem resistance in Enterobacteriaceae may be related either to the association of a decrease in bacterial outer-membrane permeability with overexpression of b-lactamases possessing a very weak carbapenemase activity, or to a b-lactamase with strong hydrolytic activity towards carbapenems, i.e. a carbapenemase. Differentiation of these mechanisms may have consequences for the clinical management of patients and prevention of nosocomial outbreaks. – 5 The main carbapenemases described in Enterobacteriaceae are the Ambler class A KPC enzymes, Ambler class B b-lactamases (metallo-b-lactamases) of VIM, IMP and NDM types, and Ambler class D carbapenemases of theOXA-48type. Thecarbapenemase-producingEnterobacteriaceaeareusually resistanttomanyotherb-lactamandnon-b-lactam antibiotics, giving rise to multiresistant and pandrug-resistant isolates. Methods