Evaluation of the Carba NP Test in Oregon, 2013

Carbapenem-resistant Enterobacteriaceae (CRE) are an urgent public health threat. We evaluated the capacity of the Carba NP test to detect carbapenemase production in 206 isolates: 143 Enterobacteriaceae identified by Oregon's CRE surveillance program in 2013 and 63 known carbapenemase-positive organisms. Overall, test sensitivity and specificity were 89% (59/66 isolates; 95% confidence interval [CI], 81 to 97%) and 100% (140/140 isolates; 95% CI, 98 to 100%), respectively. All KPC, NDM-1, VIM, and IMP producers but no (0/7 isolates) OXA-48-like strains were Carba NP positive prior to a post hoc protocol modification. We subsequently incorporated Carba NP into Oregon's CRE screening algorithm.