RESIST-6 O.O.K.N.V. I. - The Big 5 carbapenemases + OXA-163
This new immunochromatography test allows the identification of the following carbapenemases: OXA-48-like, KPC, NDM IMP and VIM carbapenemases from culture.
In addition it also differentiates the non-carbapenemase OXA variants (OXA-163 like) from the carbapenemase producing OXA-48 like
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Non- carbapenemase producing OXAs. A false positive report?
Some OXA-48 detection/identification products, both commercial PCR and lateral flow, do not discriminate between carbapenemase producing and non-carbapenemase producing OXA variants. OXA-48 variants have medium or high carbapenemase activity. They are often susceptible to expanded-spectrum cephalosporins but resistant to carbapenems. OXA-163 variants have little or no carbapenemase activity. They are often resistant to expanded-spectrum cephalosporins but susceptible to carbapenems. 
Whilst treatment should be guided by susceptibility results it is advantageous to have insight into the antibiotic groups that may or may not be affected by the beta-lactamases present.
This chart shows the resistance levels to be expected from various carbapenemases. It highlights that whilst OXA-48 may be treated with 3rd & 4th generation carbapenems OXA-163 cannot; yet can be treated with some carbapenems.
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IMP variants - improved detection
How good are current rapid products at recognising IMP carbapenemases? Publications have shown wide variance in sensitivity NG Carba5 - 55% 75% - ref 1, ref 2 Cepheid - 44% 71% - ref1, ref 3 The new RESIST IMP has 97%* sensitivity *The RESIST figure is work done on a collection of 94 fully-characterised IMP strains at the National Reference Laboratory for MDR Gram Negatives (Belgium) and University Hospital xxx So why the wide differences in sensitivity? There are 70+ IMP variants, antibodies have to be raised to epitopes which are common to a number of variants. The chosen epitope, used to raise an antibody for use in a diagnostic test, will be present in a wide range of variants. It is important that the key variants (decided by frequency and geography) are covered. IMP variants detected 
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RESIST-6 O.O.K.N.V. I.
consists of two cassettes. One cassette for NDM + IMP + VIM and the other for OXA-48 + OXA 163 + KPC. This chart shows the variants that are recognised.
consists of two cassettes. One cassette for NDM + IMP + VIM and the other for OXA-48 + OXA 163 + KPC. This chart shows the variants that are recognised.
RESIST-6 O.O.K.N.V. I. components have the extremely high sensitivity and specificity associated with other products in the RESIST range.
