A nitrocefin disc supplemented with ertapenem for rapid screening of carbapenemase-producing Enterobacteriaceae

Reliable, simple and rapid methods for laboratory detection of carbapenemases are important for an appropriate antibiotic administration. A nitrocefin disc containing ertapenem for rapid screening of carbapenemase production among Enterobacteriaceae is developed in the present study. A total of 87 molecularly-confirmed Enterobacteriaceae including 31 carbapenemase producers and 56 non-carbapenemase producers, were tested with nitrocefin discs supplemented with and without ertapenem (20 μg/disc). Nitrocefin discs with ertapenem successfully discriminated all 31 carbapenemase and all non-carbapenemase producers within 30 minutes. The sensitivity and specificity of the method were 100%. The minimum inhibitory concentrations (MICs) of ertapenem against all carbapenemase-producing isolates ranged from 1 to ≥256 μg/mL. This simple test could help to minimize the treatment failure and control the dissemination of infections caused by carbapenemase-associated resistant bacteria. It is a promising approach that could be performed routinely in any laboratory.