Prospective evaluation of the Amplidiag® CarbaR+VRE assay for direct screening of carbapenemase producing gram-negative bacilli from rectal swabs

Abstract This prospective study evaluated the ability of the qPCR Amplidiag® CarbaR+VRE assay to detect Carbapenemase-producing Gram-negative bacilli (CP-GNB) directly on 1830 rectal swabs extracted using the fully automated platform Amplidiag® Easy instrument. The Amplidiag® CarbaR+VRE assay gave a positive signal for 94 rectal swabs, whereas only 70 grew with CP-GNB on chromogenic media including 4 VIM-producing P. aeruginosa, 8 OXA-23-producing A. baumannii and 58 carbapenemase-producing Enterobacteriaceae. All the CP-GNB culture positive were detected by the Amplidiag® CarbaR+VRE assay. Twenty-four qPCR positive and culture negative samples were further investigated using targeted PCRs and subsequent DNA sequencing. Seventeen and seven of these were positive and negative with PCR/DNA sequencing, respectively. Taken together, the Amplidiag® CarbaR+VRE could detect carbapenemases directly from rectal swabs in 3 h30 using a fully automated platform and showed high biological performances (sensitivity, specificity, negative and positive predictive values were 100, 98.6, 100 and 74.5%, respectively).