Detection of carbapenemases activity in Enterobacteriaceae: Comparison of the carbapenem inactivation method versus the Carba NP test
. J Antimicrob Chemother 2016; 71(1): 274-6.
The carbapenem inactivation method (CIM), a simple and low-cost alternative for the Carba NP test
to assess phenotypic carbapenemase activity in gram-negative rods.
Carbapenemase production was determined by CarbAcineto NP test
(5) and the presence of carbapenemase encoding genes was investigated by PCR and sequencing for blaOXA-23, blaOXA-24, [bla.sub.OXA-51], [bla.sub.OXA-58], [bla.sub.OXA-143], [bla.sub.IMP-1], [bla.sub.NDM], [bla.sub.VIM], [bla.sub.SPM] and [bla.sub.KPC].
(23,24) In 2016, the CLSI suggested that confirmatory tests such as the MHT, the Carba NP test
and/or a molecular technique should be performed when Enterobacteriaceae isolates are associated with a suspicion of carbepenemase production based on updated carbapenem breakpoints (imipenem or meropenem or ertapenem MICs of at least [greater than or equal to] 2[micro]g/mLTable 1).
We recommend that those clinical laboratories without molecular set-up can use the Rapidec Carba NP test
for routine screening of carbapenemases in imipenem/meropenem-resistant Acinetobacter sp.
We used microbroth dilution susceptibility testing (5) to select and verify 130 gram-negative nonrepeat isolates (i.e., each isolate was tested once) and then tested the isolates for carbapenemase production by using the Carba NP test
as previously described (6).
Detailed data about each NP test
are reported in Table 2.
Although the sensitivity of the real-time PCR, DD with IMP, and BMD with MRP were equal, real-time PCR had the best specificity (100%), which was equalled only by that of the Carba NP test
The study assessed the ability of the Carba NP test
to properly identify 59 of 201 clinical isolates as carbapenemase producers.
The ADF, DF-GLS and NP test
the null of unit root whereas the KPSS tests the null of stationarity.
Rudy Garcia is the strategic marketing manager and technical advisor at NP Test
. He has more than 25 years of experience in IC test and is an IEEE member active in test-related forums such as the International Test Conference and the International Technology Roadmap for Semiconductors.