Objectives: To evaluate the performance of the eazyplex(®) SuperBug CRE system, a loop-mediated isothermal amplification (LAMP)-based system, for confirming the presence of carbapenemases in addition to CTX-M-type ESBLs in previously genotypically and/or phenotypically characterized clinical Enterobacteriaceae isolates recovered in two centres in Spain.
Methods: A collection of 94 carbapenemase-producing strains previously characterized by conventional PCR and sequencing and a total of 45 prospectively collected isolates with phenotypes compatible with the presence of a carbapenemase were tested with the eazyplex(®) SuperBug CRE system. In both cases, the presence of an ESBL was also assessed. Results were evaluated to establish the accuracy of this rapid LAMP-based system as well as to determine the concordance between all approaches.
Results: The eazyplex(®) SuperBug CRE system correctly detected bla carbapenemase genes with or without blaCTX-M genes in 100% of the molecularly characterized strains. Absolute concordance (100%) was also observed in the case of isolates with phenotypes compatible with the presence of a carbapenemase with or without an ESBL inferred by susceptibility patterns and phenotypic inhibitory profiles. Determinations performed with the eazyplex(®) SuperBug CRE system took 15 min.
Conclusions: The eazyplex(®) SuperBug CRE system proved to be a powerful tool for the detection of different carbapenemases as well as CTX-M-type ESBLs in Enterobacteriaceae with a rapid resolution time. The test has the high-performance parameters attributable to the sensitivity and specificity already demonstrated by LAMP-based assays. These results assure the usefulness of this test for routine rapid confirmation of carbapenemase-producing Enterobacteriaceae.
Keywords: LAMP; isothermal amplification; β-lactamases.
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