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Detection of carbapenemase-producing Enterobacteriaceae with a commercial DNA microarray
Abstract
The Check-MDR CT102 DNA microarray enables detection of the most prevalent carbapenemases (NDM, VIM, KPC, OXA-48 and IMP) and extended-spectrum β-lactamase (ESBL) gene families (SHV, TEM and CTX-M). The test performance of this microarray was evaluated with 95 Enterobacteriaceae isolates suspected of being carbapenemase producers, i.e. with meropenem MICs ≥0.5 mg l−1. The collection of isolates contained 70 carbapenemase-producing isolates, including 37 bla KPC-, 20 bla VIM-, five bla OXA-48-, four bla KPC/bla VIM- and four bla NDM-positive isolates; and 25 carbapenemase-gene-negative isolates. ESBLs were produced by 51 of the isolates. PCR and sequencing of β-lactamase genes was used as reference test. For detection of carbapenemases, the sensitivity of the microarray was 97 % (68/70), with 100 % specificity. The two negative isolates tested positive when the microarray test was repeated; these isolates were an OXA-48- and a KPC-producing isolate. For ESBL detection, the sensitivity was 100 % (51/51) and the specificity was 98 % (43/44), although 20 % of the SHV-12 ESBLs were categorized as SHV-2-like ESBLs. In conclusion, the CDT102 microarray is a rapid and accurate tool for the detection of carbapenemase and ESBL genes, although the array seems less suitable for epidemiology of ESBL genes.
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© 2012 SGM