Epidemiology Research Today is a free monthly online journal that collates and summarizes the latest research about Epidemiology, including details on twin studies, statistics, environmental and genetic factors.

Carbapenem resistance in Acinetobacter baumannii: mechanisms and epidemiology.

Poirel L, Nordmann P

Service de Bactériologie-Virologie, Hôpital de Bicêtre, South-Paris Medical School, University Paris XI, Le Kremlin-Bicêtre, France. laurent.poirel@bct.ap-hop-paris.fr

The increasing trend of carbapenem resistance in Acinetobacter baumannii worldwide is a concern since it limits drastically the range of therapeutic alternatives. Metallo-beta-lactamases (VIM, IMP, SIM) have been reported worldwide, especially in Asia and western Europe, and confer resistance to all beta-lactams except aztreonam. The most widespread beta-lactamases with carbapenemase activity in A. baumannii are carbapenem-hydrolysing class D beta-lactamases (CHDLs) that are mostly specific for this species. These enzymes belong to three unrelated groups of clavulanic acid-resistant beta-lactamases, represented by OXA-23, OXA-24 and OXA-58, that can be either plasmid- or chromosomally-encoded. A. baumannii also possesses an intrinsic carbapenem-hydrolysing oxacillinase, the expression of which may vary, that may play a role in carbapenem resistance. In addition to beta-lactamases, carbapenem resistance in A. baumannii may also result from porin or penicillin-binding protein modifications. Several porins, including the 33-kDa CarO protein, that constitute a pore channel for influx of carbapenems, might be involved in carbapenem resistance.

Published 2 August 2006 in Clin Microbiol Infect, 12(9): 826-36.
Full-text of this article is available online (may require subscription).

© 2005-2008 Epidemiology Research Today. All Rights Reserved.