Beschreibung:
<jats:title>Abstract</jats:title>
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<jats:title>Objectives</jats:title>
<jats:p>To assess the performance of three commercial molecular assays for detecting major families of carbapenemases in pure bacterial isolates.</jats:p>
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<jats:title>Methods</jats:title>
<jats:p>A panel of 450 isolates with previously defined carbapenem resistance mechanisms was tested using the Check-Direct CPE kit, the eazyplex® SuperBug complete A kit and the Xpert® Carba-R kit. Isolates included 438 Enterobacteriaceae and 12 Pseudomonas spp. comprising 100 isolates each with KPC, NDM, VIM or OXA-48-like enzymes, two isolates producing both an NDM and an OXA-48-like enzyme, 24 IMP producers and 24 isolates without a known carbapenemase gene. Discordant results (commercial versus in-house) were investigated using in-house PCR and amplicons were sequenced to define the carbapenemase allele present.</jats:p>
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<jats:title>Results</jats:title>
<jats:p>All three commercial assays detected all isolates with KPC, VIM, NDM and classic OXA-48 carbapenemases (no false-negatives). Isolates producing the OXA-181 variant (n = 18) were not detected by the Xpert® Carba-R kit or the eazyplex® SuperBug complete A kit, but were subsequently detected with modified versions of these kits. Only the Xpert® Carba-R kit could detect IMP carbapenemases, although this was limited to the IMP-1 subgroup. Invalid or false-positive results were either not observed when following the manufacturer's protocols or were eliminated by making simple interpretative adjustments to allow use with bacterial isolates rather than clinical samples.</jats:p>
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<jats:title>Conclusions</jats:title>
<jats:p>Commercial assays offer a reliable means of detecting bacteria with clinically significant carbapenemases. Coverage of some assays required expansion to maximize the sensitivity for OXA-48-like carbapenemases. Choice will ultimately depend on preferred gene coverage, intended throughput, cost and ability to fit into local workflows.</jats:p>
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