Detection of rare carbapenemases in Enterobacterales—comparison of two colorimetric and three CIM-based carbapenemase assays
In: Microbiology Spectrum ; volume 12, issue 2 ; ISSN 2165-0497, 2024
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Zugriff:
Rapid and reliable detection of carbapenemase-producing Enterobacterales (CPE) is crucial for prompt treatment and infection control. Most assays target the primary four enzymes (KPC, OXA-48-like, VIM, and NDM), often missing less common variants (e.g., GES, IMI, OXA-23, and OXA-58). Therefore, assays based on the hydrolysis of carbapenems are recommended in addition to differentiation tests such as PCR or immunochromatographic assays. The aim of this study was to compare the currently Clinical and Laboratory Standards Institute (CLSI)-recommended tests mCIM (modified carbapenem inactivation method) and Carba NP with new colorimetric tests (NitroSpeed-Carba NP) and novel variations of the carbapenem inactivation method (CIM) such as simplified CIM (sCIM) or modified zinc-supplemented CIM (mzCIM). The challenge collection included 205 clinical isolates, 139 CPE vs 66 non-CPE. Among all 205 isolates, the sensitivity/specificity of mCIM was 81.3%/98.5%, Carba NP 76.3%/100%, NitroSpeed-Carba NP 86.3%/78.8%, sCIM 100%/94%, and mzCIM 97.8%/98.5%. For rare carbapenemases ( n = 48), the sensitivity of mzCIM (98.3%) and sCIM (100%) was higher than that of mCIM (60.4%), Carba NP (50%), or NitroSpeed-Carba NP (70.2%). Most indeterminate results occurred for mCIM (14.4%), Carba NP (8.2%), and sCIM (6.3%). The detection of rare carbapenemases remains challenging with the currently recommended assays. The CIM-based tests demonstrated superior sensitivity, with sCIM and mzCIM outperforming the currently recommended mCIM and Carba NP, especially among isolates with weakly hydrolyzing carbapenemases (e.g., OXA-23 and OXA-58). Although colorimetric assays provide more rapid results, laboratories have to be aware of the low sensitivity for rare carbapenemases. Both sCIM and the new mzCIM performed well, are cost-effective, and can easily be implemented in any laboratory. IMPORTANCE Detection of so-called rare carbapenemases (e.g., GES, IMI, OXA-23, and OXA-58) in Enterobacterales is challenging, and data on the ...
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Detection of rare carbapenemases in Enterobacterales—comparison of two colorimetric and three CIM-based carbapenemase assays
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Autor/in / Beteiligte Person: | Schaffarczyk, Lukas ; Noster, Janina ; Stelzer, Yvonne ; Sattler, Janko ; Gatermann, Sören ; Hamprecht, Axel ; Babiker, Ahmed |
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Zeitschrift: | Microbiology Spectrum ; volume 12, issue 2 ; ISSN 2165-0497, 2024 |
Veröffentlichung: | American Society for Microbiology, 2024 |
Medientyp: | academicJournal |
DOI: | 10.1128/spectrum.03015-23 |
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