Figure 1. Representative results of the Carba NP test. The Carba NP
test was performed with a noncarbapenemase producer (Escherichia
coli producing the extended-spectrum β-lactamase CTX-M-15,
upper panel) and with a carbapenemase producer (Klebsiella
pneumoniae–producing New Delhi metallo-β-lactamase-1,
lower panel) in a reaction medium without (left panel) and with
(right panel) imipenem. Uninoculated wells are shown as controls.
Photographs were taken after a 1.5-hour incubation. A color
version of this fi gure is available online (wwwnc.cdc.gov/EID/
article/18/9/12-0355-F1.htm)