Volume 18, Number 9—September 2012
Author affiliations: Faculté de Médecine Paris Sud, Le Kremlin-Bicêtre, France (P. Nordmann, L. Poirel, L. Dortet); and Institut National de la Santé et de la Recherche Médicale, Paris, France (P. Nordmann, L. Poirel, L. Dortet)
To rapidly identify carbapenemase producers in Enterobacteriaceae, we developed the Carba NP test. The test uses isolated bacterial colonies and is based on in vitro hydrolysis of a carbapenem, imipenem. It was 100% sensitive and specific compared with molecular-based techniques. This rapid (<2 any="any" be="be" hours="hours" implemented="implemented" in="in" inexpensive="inexpensive" laboratory.="laboratory." may="may" p="p" technique="technique">2>
Multidrug resistance is emerging worldwide at an alarming rate among a variety of bacterial species, causing both community-acquired and nosocomial infections (1). Carbapenems, the last line of therapy, are now frequently needed to treat nosocomial infections, and increasing resistance to this class of β-lactams leaves the health care system with almost no effective drugs (1). However, reports of carbapenem-resistant Enterobacteriaceae have increased (2,3). Resistance may be related to association of a decrease in bacterial outer-membrane permeability, with overexpression of β-lactamases with no carbapenemase activity or to expression of carbapenemases (2,4,5). Spread of carbapenemase producers is a relevant clinical issue because carbapenemases confer resistance to most β-lactams (2). Various carbapenemases have been reported in Enterobacteriaceae, such as the following types: Klebsiella pneumoniae carbapenemase (KPC; Ambler class A); Verona integron–encoded metallo-β-lactamase (VIM), imipenemase (IMP), New Delhi metallo-β-lactamase (NDM) (all Ambler class B); and oxacillinase-48 (OXA-48; Ambler class D) (2,4–6). In addition, carbapenemase producers are usually associated with many other non–β-lactam resistance determinants, which give rise to multidrug- and pandrug-resistant isolates (2,3,7).