Youri Glupczynski1, Stéphanie Evrard2, Isabelle Ote3, Pascal Mertens3, Te-Din Huang2, Thierry Leclipteux3, Pierre Bogaerts2. 1. National Reference Laboratory for Monitoring of Antimicrobial Resistance in Gram-Negative Bacteria, CHU Dinant-Godinne, UCL Namur, B-5530 Yvoir, Belgium gerald.glupczynski@uclouvain.be. 2. National Reference Laboratory for Monitoring of Antimicrobial Resistance in Gram-Negative Bacteria, CHU Dinant-Godinne, UCL Namur, B-5530 Yvoir, Belgium. 3. Coris BioConcept, Crealys Park, B-5032 Gembloux, Belgium.
Abstract
BACKGROUND: Rapid detection and confirmation of carbapenemases remains very challenging for diagnostic laboratories. OBJECTIVES: The objective of this study was to assess the performance of two new immunochromatographic (IC) commercial assays for the rapid detection of OXA-48-producing and KPC-producing Enterobacteriaceae in pure bacterial isolates. METHODS: A panel of 92 bacterial isolates predominantly including carbapenem-non-susceptible Enterobacteriaceae with previously defined carbapenem resistance mechanisms was tested. Then, 342 consecutive carbapenem-non-susceptible Enterobacteriaceae isolates referred to the reference laboratory were investigated prospectively in parallel with other phenotypic tests and with multiplex PCR and sequencing as the gold standard. RESULTS: In the collection panel, each of the two IC assays correctly detected all 30 OXA-48-like-producing isolates and 25 KPC-producing isolates, whatever the species, their association with other β-lactamases and the level of resistance to carbapenems. All other carbapenemase producers and all non-carbapenemase-producing isolates yielded negative results with both tests. In the prospective evaluation, all OXA-48-like-producing Enterobacteriaceae isolates (n = 130) and KPC-producing Enterobacteriaceae isolates (n = 33) were correctly detected by the individual IC assays, while 179 non-OXA-48-like-producing and non-KPC-producing strains (137 non-carbapenemase producers and 42 isolates belonging to other carbapenemase family types) yielded negative results. Thus, each assay yielded 100% sensitivity and 100% specificity for the detection of OXA-48-like or KPC enzymes, respectively, at 15 min. CONCLUSIONS: The two IC assays allow rapid and reliable direct confirmation of OXA-48 and KPC carbapenemases from culture colonies and appear to be very useful additions to the existing tests, obviating the need for more costly characterization by molecular amplification methods.
BACKGROUND: Rapid detection and confirmation of carbapenemases remains very challenging for diagnostic laboratories. OBJECTIVES: The objective of this study was to assess the performance of two new immunochromatographic (IC) commercial assays for the rapid detection of OXA-48-producing and KPC-producing Enterobacteriaceae in pure bacterial isolates. METHODS: A panel of 92 bacterial isolates predominantly including carbapenem-non-susceptible Enterobacteriaceae with previously defined carbapenem resistance mechanisms was tested. Then, 342 consecutive carbapenem-non-susceptible Enterobacteriaceae isolates referred to the reference laboratory were investigated prospectively in parallel with other phenotypic tests and with multiplex PCR and sequencing as the gold standard. RESULTS: In the collection panel, each of the two IC assays correctly detected all 30 OXA-48-like-producing isolates and 25 KPC-producing isolates, whatever the species, their association with other β-lactamases and the level of resistance to carbapenems. All other carbapenemase producers and all non-carbapenemase-producing isolates yielded negative results with both tests. In the prospective evaluation, all OXA-48-like-producing Enterobacteriaceae isolates (n = 130) and KPC-producing Enterobacteriaceae isolates (n = 33) were correctly detected by the individual IC assays, while 179 non-OXA-48-like-producing and non-KPC-producing strains (137 non-carbapenemase producers and 42 isolates belonging to other carbapenemase family types) yielded negative results. Thus, each assay yielded 100% sensitivity and 100% specificity for the detection of OXA-48-like or KPC enzymes, respectively, at 15 min. CONCLUSIONS: The two IC assays allow rapid and reliable direct confirmation of OXA-48 and KPC carbapenemases from culture colonies and appear to be very useful additions to the existing tests, obviating the need for more costly characterization by molecular amplification methods.
Authors: Pranita D Tamma; Belita N A Opene; Andrew Gluck; Krizia K Chambers; Karen C Carroll; Patricia J Simner Journal: J Clin Microbiol Date: 2017-01-11 Impact factor: 5.948